Getting Air Out Of Motorcycle Brake Systems : Mini Skills

[@randomrides]

That's really handy and good to know, does it work with the twin disc/ callipers on the front of the Bandits? Thanks again.

[@MotoMirius]

Oh yes it does. Anywhere you have a loop of brake hose that goes up and then down, you will get trapped air. You can bleed it as much as you like, the fluid will slide right past the bubbles. I have a video coming up where I bled the front brakes on the Bandit, so assuming I got it on camera, you will see it there! Skäl David

[@stvnkll]

Very dangerous misinformation, people could die following this advice, if you take my advice you'll take the video down before someone's killed.

[@MotoMirius]

Thanks for your opinion

[@paulhartwell8460]

David I will try this my brakes have recently been bled but i still have quite a lot of travel on the brake lever; their not spongy but I feel that they should bite sooner. Not sure why Jed thinks this advice will kill people; surely you should try to get as much air out of the system as possible! Regards Paul.

[@MotoMirius]

Cheers Paul. If the system is bled and the lever is firm then you shouldn’t have excess travel. Have you got adjustable levers and changed the setting? I guess Jed isn’t aware that mechanics and engineers have used this technique for decades without killing people. Skäl. David

[@gomiko1608]

Four years later, this video is still helpful! took me about 30 min while shake my brake line to get the air out of my lines. Thanks for the tip! I was bleeding the brake over and over and no luck but your tip worked!

[@MotoMirius]

Great job, well done!

[@ridefitnation]

Excellent and very simple process. I added a 20” bar and had to bleed breaks because it’s ABS. But this is a really simple process. Well done.

[@MotoMirius]

Glad it helped!

[@alanbennett2855]

Thank you so much for posting this video. I could not get the air out of my front brake no matter how many timed I tried. You sir just saved me from a bad day. I certainly appreciate it. Keep posting solutions. Thanks

[@MotoMirius]

Glad to hear that helped. Sometimes it's the little things that make the biggest difference. Skäl David

[@Randomperson12-f2l]

So just keep barley using the break until you get pressure?

[@nativerebel3718]

Wish I would of watch this video about six weeks ago, I helped a buddy replace his front break line and we spent two hours trying to bleed his breaks and not get anywhere, took it to a shop to replace the tire and had them try bleeding it and they didn’t get anywhere. I ended up zip tying the lever and letting it sit for a few days and it was bled out when I got back to it

[@MotoMirius]

Knowledge is power. Everyone assumes the pumping fluid method is how you do it. But it’s just what mechanics do because they need to do the job in the shortest time possible even if it doesn’t always work so well. Good job on getting it done. Skäl. David

[@dimitarpetrov3047]

Well done mate. You made my life easier!!! I spent £30 for break fluid till I saw your video. Thank you very much

[@MotoMirius]

Thanks and you are very welcome!

[@nspinicelli]

Helpful tip: to get ALL of the air out, pull in the brake lever and tie it off against the grip. Let it sit overnight. Come out in the morning and do what's shown in the video one more time. What's supposed to happen is the air bubbles will gather into large bubbles, making it easier to purge. Works like a charm, good to go for heavy braking on racetracks.

[@MotoMirius]

I do tend to tie back if I need it, as I mentioned in the video. Isn't always necessary but never hurts. Lots of theories - I've heard the opposite which is that the pressure in the fluid breaks down the larger bubbles into smaller ones which flow up easier. Skäl David

[@CptSlow89]

It lasts for a short time... You still need to bleed it.

[@peterock8217]

He said that in the video

[@jonb6660]

Thanks, very logical when you explain it. An added tip I bought releasable cable ties 7.6mm by 30mm off eBay. I use them on front brake lever when transporting my bike I didn't realize it would help the brake bleeding. I'm finding lots more uses for those cable ties 👍

[@MotoMirius]

Thanks. Can never have too many releasable cable ties!

[@edwardleniston1076]

Great tip David, I will try this on my Blackbird.

[@MotoMirius]

Cheers Edward. It can mean taking the calipers off so that you can allow the air to rise uphill - it will never go down! Skäl David

[@joselitobrigante]

I own a beautiful 1988 XT600, single piston front brake. I spent like half a day pumping the hell out of that caliper and I couldnt feel any pressure, suddenly I watched this video and now my front brake works again. Whats this method called? Much easier and cleaner than the classic bleeding method. Thank you Sir. Suscribing now

[@MotoMirius]

Great work. I'm not sure I've ever seen a name for it.

[@Jomster777]

Just a question: what do bubbles do inside your caliper? How do they affect your brake system?

[@MotoMirius]

Hydraulic fluid can be compared to liquid metal - it flows but can’t be crushed. Air however squashes easily. If you have air in the system when you squeeze the lever first you have to squash all the air before the fluid will move and the pads apply pressure so that the brakes will operate. Bubbles have no function and shouldn’t be present but result from water contamination of the fluid (which also squashes). As the water boils from the heat of braking it creates air.

[@michaelmckellar7620]

You can compress air. Fluids cannot be compressed.

[@CX2Pilot]

Thanks for making this video, it worked great on my minibike! Just to be 100% sure that all the air was out of the system I did a quick gravity bleed on the brake caliper after I used your method.

[@MotoMirius]

Nice work!

[@CX2Pilot]

​@@MotoMiriusIf you leave the brake lever pulled in overnight to get any air out like you show in the video does the cap on the brake reservoir need to be off or can you leave it on?

[@MotoMirius]

Normally you'd leave it on @@CX2Pilot

[@steviefix6870]

Brilliant video. Simple to do and saved me taking to a mechanic! Works better than ever now! Much appreciated

[@MotoMirius]

Glad to of help and more importantly, well done. 👍. Skäl. David

[@StuartBrogden]

Helpful. I put new braided hoses and new master cylinder on my old Honda Sabre and I've pushed fluid up from the caliper and coaxed air out of the master as shown in this video. There is absolutely no resistance in the brake handle at all. Nothing.

[@MotoMirius]

It will depend on your brake line routing - if there are air traps then this will never work, you need to have an uphill run all the way - because air rises. If you have the line routing right then this will work - it can't not work because it is how the brake designers designed the system to work - bike designers sometimes create loops in the cable and ABS units also cause air traps.

[@adrianstensrud]

Great! Will definitively do this. Another added benefit is that I will be able to see the fluid level, as my sight glass is completely white (and I can't change it anytime soon).

[@MotoMirius]

Good luck with that, sight glasses can be a real pain!

[@adrianstensrud]

@@MotoMirius Yeah, so I've noticed! Living in Europe it seems I will have to order from the US or China. Either way, I will pay multiple times more for them than for the shipping.. it's not an "going broke" amount, just super irritating. Went to the local Honda workshop and they checked the fluid and said it's not the freshest, but no danger yet, and that they did not keep these in stock - which I had hoped considering how many probably need to change them as we have 9 months of scorching sun per year where I live - and so many ride bikes here. But alas, no.

[@frankolwenda5128]

Thank you for this. Today my brakes got stuck. The lever got really hard and I could just hear a wild screeching sound while riding. Leaving the caliper to cool was a short term fix but not super effective. I think I will try this tomorrow

[@MotoMirius]

Sounds like the pistons are getting sticky. Good chance you will need a caliper rebuild or at least cleaning the pistons. Simple enough jobs, so good luck with that.

[@thecreed3950]

would this work on the rear as well or only the front because of the vertical pipe work ?

[@MotoMirius]

As you will see in the comments - only the front. But the rear is easy to bleed - so long as you don't have ABS which always creates issues because of the pipework routing. The mistake people make when bleeding the rear is to keep opening and closing off the bleed nipple. Fill the reservoir then open the bleed nipple and keep pumping until the reservoir is nearly empty (never let it go empty) then close the bleed nipple, refill the reservoir and repeat a few times.

[@mehanicigor6893]

I own and worked on many bikes and always used this trick and never had problem !

[@MotoMirius]

It’s a very old trick!

[@Nathanb700]

I tried squeezing the brake a little to see if any air bubbles show in my brake fluid reservoir but none appeared and my brake pads don’t want to grip onto the disc - I also fitted a new calliper

[@MotoMirius]

Air in the system will make the lever soft - but the pads will still grip. It sounds like you have a different issue. Perhaps there is an issue with the caliper?

[@lama2584]

i was swapping my clutch lever but noticed afer toping up brake fluid there was no resistance in the clutch. When i tried to do the slight pull in many repetitions i started getting air out of the system and in around 15-20 min i had taken all the air out. Thank you !

[@MotoMirius]

Great job, well done!

[@josholson9642]

This is the best instruction I have seen and it works!

[@MotoMirius]

Thanks. I lay no claim to the idea, but I like it because it works! Skäl David

[@GR8WHITEC5]

Watching this video confuses me. You open the Master Cylinder to let air out, but an open cylinder is exposed to air. So when you seal it off, there is air in there. Unless what you are referring to is what I consider my Brake Fluid Reservoir? I bled all my fluid, rebuild my calipers, refilled with brake fluid, bled, test bedded the brake pads, but the feont brakes don't feel like they are biting. I went home and bled the brakes again. Question: If air rises, and I am bleeding feom the calipers first, not the master cylinder, am I pulling the air back down? Since I did two bleeds now, should I focus on bleeding the master cylinder, where air rises to? Or focus on opening my Brake Fluid Reservoir and gently pumping like you demonstrated?

[@MotoMirius]

Master cylinder/ reservoir has to be opened to add fluid. Yes, there will be some air in there. I've seen people try to go overboard about this, but it isn't rocket science and the engineers who designed the system knew what they were doing and what the constraints are. Air can be felt by a soft lever - if the lever is solid and the brakes are not biting then it's likely a mechanical issue in the calipers. Air will rise from the calipers - if you create an uphill route. You cannot easily pull air down - unless you force it down. There is no need to bleed it from the calipers as the air will rise to the top of the system - or to the air trap in the system if you have a loop in the routing. The process demonstrated here cannot work if you have an air trap in the system - loop over front brake, ABS etc.

[@geofffletcher]

Hi I changed my brake pads the other week and now the lever is tight and creaky! I've bled the system 3 times but to no avail. Tried your method but no bubbles what so ever! Any suggestions? Your comment at the end regarding overfilling the reservoir when fitting new pads may be relevant?

[@MotoMirius]

You can always remove the cover and check the level. If necessary remove some fluid and see if it makes a difference. It will be difficult to remote diagnose this - hands on and often fresh eyes are invaluable. Good luck!

[@Juppie902]

Help! Im stuck with a weird situation I am doing my bike service and replacing its brake fluid, I did by the mechanic book: open reservoir cap, open nipple, crack open the bleed bolt, attach hose. Pump brake lever and keep pressed, open bleed bolt, fluid came out and replaced with new from the top, until I saw clear fluid coming out again. Close the bleed bolt, release lever and fill cylinder with more new fluid. Did this on rear brake - now handle is firm and bike braking and ABS works. Did this on front - handle like spaghetti braking non existant and ABS doesnt engage over 20 km/h, the lever is fully pressed. I did bleed it again but the lever remained soft. No air bubbles seen in bleeding fluid. Where is the air ?! Also: when bleed valve is closed and cylinder cover open, pressing the brake lever normally (not too fast not too slow) will cause fluid to fire all over the place. When releasing nothing. What does this mean ?

[@MotoMirius]

Pressing the lever too fast when the top is off will cause fluid rebound - if it happen, it was too fast. ABS systems can be hard to bleed if air is allowed into the system - most will have air traps that are hard to bleed and may need a pressure bleed to shift - the fluid can bypass the bubble during bleeding but the air compresses under pressure giving a soft feel.

[@yuutatogashi3229]

Mr mirius I hope you read this comment to you what is the good oil engine and also for brake hand and foot brake I use 150cc motorcycle and last thing oil cooler thank you very much ciao🙂php

[@MotoMirius]

The good oil is the one recommended for your bike by a reputable oil manufacturer or the oil recommended by your bike manufacturer. Unless you are racing there is no reason to move away from this - you could spend the next 10 years arguing on the internet about what is the best oil - because there isn't one - not that anyone can agree on. Brake fluid is the same - just buy from a good manufacturer to the spec for your bike - nearly always DOT4, and make sure you are not buying anything fake. I can't comment on oil coolers.

[@Altair885]

No, you shouldn't get air getting in through your calipers unless they're shagged! Bike brakes are totally sealed from the outside atmosphere, the vent in the cap of the brake fluid reservoir is to allow air in/out so that the rubber bellows can move as brake fluid is displaced in our out of the reservoir during normal braking operation. If you are getting air in your brakes then you have a leak in the system that shouldn't be there, a good sign that the system needs an overhaul. Also it should be mentioned that the line into the calipers is usually at least halfway down on most, this means if air were to be getting into the system and traveling up to the master cylinder, then the caliper would already be partly full of air anyway and you'd already have spongy brakes, or even no brakes! As far as bleeding goes, the best method is usually vacuum bleeding at the caliper. Sometimes on some systems a better method is reverse pressure bleeding where fluid is fed into the caliper and back up to the reservoir, but this depends on the style of caliper and hose placement etc.

[@pingus8133]

What about the rear brakes on a big dog Mastiff the calipers barely above the master cylinder, and it shakes like mad and I still got air

[@MotoMirius]

This won't work where the line is flat. You need to brute force it because the air won't want to move sidewise. Remove the top of the reservoir, top fully up, crack open bleed screw, pump brake pedal until reservoir is almost empty, close the bleed screw. Refill reservoir and repeat until pedal isn't soft. Do NOT open and shut bleed screw during bleeding. Do NOT allow the reservoir to run dry - make sure that there is always fluid in it. Good luck

[@davidhoward8951]

I can't get a firm pedal I have almost used a pint of fluid on my DRZ Supermoto and I noticed when I put the tube on there with the little it's like the handyman bleeding system I see air bubbles

[@MotoMirius]

Pedal or lever? Rear brakes don't really like this system because it's a flat line and the air gets trapped in the line. I have a different process I use for rear brakes (assuming no ABS)

[@sanesaint8725]

Don't crack the bottom if it still looks good and you just need more then you might have to reverse bleed

[@wanmukhlis6872]

It means while we ride and use the brake it will keep removing air from the system if any automatically..am i right?

[@MotoMirius]

That is how the system was designed by the brake engineers yes. In practice, bike designers sometimes create air traps which prevent this.

[@nlee5034]

Just a quick question… and I’m pretty sure I know the answer, but as I just got my first bike… the trick here is breaking the seal of the master cylinder, correct? Thats what does it, I’m guessing. Otherwise you’re just squeezing the lever over and over. Is my assumption correct?

[@MotoMirius]

If you mean opening the master cylinder to the brake line to allow the air to escape up into the master cylinder, then yes - partly. That is what tying the brake lever back does. Pumping the lever does not only do this, but it puts the fluid in the line under pressure - and since brake fluid does not compress very well, it will compress and help shatter any air bubbles and with the movement of the fluid, help break them free of whatever they are stuck against.

[@TheNordmo]

Hello. What was the cause of this repair? What symptoms, before you did anything, I lost the power of the clutch. Have cleaned and refilled the brake fluid and vented the system. But there are no air bubbles in the return to the container on the handlebars ...

[@MotoMirius]

This is typically on fluid replacement. Symptoms are the ability to compress the fluid with the lever - it should go hard when pulled. But there can also be other issues not related to the fluid, especially common with failure of the clutch slave cylinder or pushrod.

[@TheNordmo]

@@MotoMirius Thx, I think it's failure of the clutch slave cylinder.

[@satyanarayanana7563]

After changing the breaks fluid in my scrambler front break is not working any suggesting ?

[@MotoMirius]

If that is all you have done then it's almost certainly air in the system. Brake fluid does not compress - think of it as liquid metal - you push one end, the fluid pushes the other end. Air is very squashy, you push one end, the air just compresses, nothing happens the other end.

[@siggy2609]

So all I have to do is take the cover off and press the lever until the bubbles come out? And then leave it tied up overnight? Cheers

[@MotoMirius]

You don’t have to take the cover off but it’s easier to to see what is happening. If you do it properly and you have a simple brake pipe layout you should not need to leave it overnight - it can help when learning this method.

[@CptSlow89]

For me what I see is spongy lever. If you put zip tie for a few hours and remove it, if you have firmer lever, you have air. I will try to get banjo bolt open and retight. Tried everything and still I think level should be firmer.

[@MotoMirius]

Zip tie overnight is a slower method and can be used to finish off. Yes, check your bolts are tight so you have no leaks - I had this recently where I had been refitting the lines and forgot to properly retighten one banjo.

[@agustinrodriguez5840]

I still have trouble with my truck I tried and I'm overnight let the air bubbles work its way out there but still having problems what do you recommend

[@MotoMirius]

Nothing beats hands on. In my experience 95% of problems are obvious hands on with a fresh pair of eyes - I can only work with what you are telling me, which means I can't see the thing you are missing.

[@ashyezza]

trying to bleed my front brakes 2004 bandit s 600 I've put hel braided lines race type so go from the m/c straight to the calipers, new pistons and seals on both calipers, new master cylinder rebuild kit, bled them the normal way and tried with a pressure bleeder and still haven't got any feel on the lever, I've put 1.5 litres of fluid through aswell.

[@MotoMirius]

Lots of potential points of failure when replacing everything. If the lever is pumping fluid to both calipers when you bleed the normal way then it sounds like the master cylinder rebuild is OK. Try leaving the lever pulled back overnight to allow the air to bleed and see if that helps.

[@KinBDutMean]

Thank you sir! I will try this before bringing my bike to the nearest shop.

[@MotoMirius]

Good luck with that.

[@silaata]

hi david,how long did it take you to get all the air out of the hose?

[@MotoMirius]

Hi, it really depends on the brake and hose setup. It can take anywhere from five minutes to an hour or more. It isn't necessarily the quickest method which is the reason you won't see mechanics use this method - they are charging by the hour so take short cuts where they can. Skäl David

[@silaata]

@@MotoMirius i just finished using this method, but it takes me about two hours. the positive side of using this technique is that its like new. thank you for sharing your idea

[@MotoMirius]

@@silaata Glad it helped, good job in doing it and it gets quicker with practice. This is a recognised method in engineering where getting it right is more important than getting an average job done in the quickest time,

[@silaata]

@@MotoMirius definitely not the quickest 9ne but certainly worth it

[@detroitpyro2859]

I want to by a red anodized cover for my bike can I take that master cylinder cover off and simply replace with the one I buy or is there more too it,. Looks like it's just two screws but I'm a newbie and don't want to mess anything up. Also don't wanna open it and oil splatter in my face if it's under pressure sorry if I sound stupid

[@MotoMirius]

I've not seen a red one, but I'm sure they are about. Cheap anodising will fade very quickly. It has to fit, you must buy one that fits. It's not under pressure but make sure the handle bars are flat when you take it off, so not on the side stand.

[@frazzle657]

Mine has this really weird issue. I've backwards bled it countless times, bench bled it, rebuilt it. Held it up at every angle, bled through the banjos etc. but there this fould fluid that tries to come up into the reservoir only under a lot of pressure. Seems to be endless, when I backwards bleed it none comes through but there is a lot of resistance. Can anyone help me? I was about to buy a new hose as I thought it was flexing under pressure

[@MotoMirius]

Bear in mind that rubber hoses have a 5 year replacement cycle, so if yours are not recent then the hose walls could well be flexing. Upgrade to steel braided lines is never a bad thing. Have you rebuilt the master cylinder?

[@vilikarac6776]

Will this work on my 125cc atv? My brake hydrulic cable touched the exahsue and leaked. I replaced the cable. But now I have nothing as far as braking. ..

[@MotoMirius]

Hydraulic brakes are hydraulic brakes no matter what they are fitted on. This relies on gravity so it won't work if your system has loops where air can be trapped - unless you unbolt the system so the air can flow uphill.

[@mike92273]

I had Vrod Muscle 2014 , my brake handle lever stuck, can’t full in. Do you know what wrong?

[@MotoMirius]

Could be a few things - wear on the pivot so it's jammed or the piston is stuck in the master cylinder and needs a rebuild for example.

[@jordanc9961]

Hi I just put on 2 x braided hoses and replaced piston seals for my sv650s, I have pressure and adequate braking but there is still air trapped in master cylinder. We took the whole system off the bike and had calipers at the highest point with no bends in the tubes, the brake was 10x firmer than when we put it back on the bike. Tried this method but the bubbles are not coming out of the reservoir (different style tank). Any ideas? New pads, new fluid, new rotors, new hoses and the brakes still are not great 😖 edit: we've done every method to bleed the system and used about 2 litres of fluid in the process

[@MotoMirius]

It's highly unlikely that air will be 'trapped' in the master cylinder - it is the highest point in the braking system for a reason and is open to atmosphere to allow air to pass in and out as the level of fluid changes - it isn't a sealed unit. If your brakes aren't great you've still got air in there - I can't see the logic in trying to bleed with the calipers at the highest point - you are trying to work against both physics and the way the brake system is designed - brake fluid will slide past trapped air which is why pumping or sucking fluid to achieve that is unreliable - put the calipers at the lowest point with a clear path to allow the air to rise up to the master cylinder. Mechanics don't use gravity bleeding because they are working against the clock so pump or suck fluid because it's fast and sortof works (but not well).

[@jordanc9961]

@@MotoMirius @Moto Mirius thanks for replying. I've got all the air out by bleeding the calipers at normal orientation bc theres nothing else coming out but liquid. However I know theres still air in the system bc when I hold calipers up and pull the brake, resistance on the lever is drastically improved. The logic being the pressure pushes the air bubbles to the nipple where I can get them out, as long as you have your reservoir upright but clearly something is not right as I lose pressure when the calipers are at the lowest. I've bled lots of brakes before, (and by using the method you're suggesting) however it's just not doing the trick which is why I'm looking for alternative means, upside down bleeding being one of them. I've left cables ties on the lever overnight, I'll update you if this has worked. Cheera

[@jordanc9961]

Success! Leaving the levers compressed overnight seems to have done the trick. Thank you for the tip! I will probably do it again tonigh just to be sure but they feel a lot firmer now than before.

[@MotoMirius]

@@jordanc9961 Good to hear that worked.

[@akkoxross5945]

Tysm this helped me a ton on a dirtbike. Another video I watched said I would have to redo the bleeding process

[@MotoMirius]

No reason to redo the bleeding process. This is a very old and well tested method.

[@GodzillaGoesGaga]

The problem with this is that ‘champagne” bubbles can stick to the side of the tubes. You need to start the engine and vibrate them out too. A good couple of slow rides will shake them loose. The repeat the process. However you might as well bleed the brakes as it’s probably quicker than riding your motorcycle.

[@aabhashbhandari4081]

Highly recommend this video before even you start the work. Excellent Explanation of the basics and principles! I replaced the brake pads on my 2011 Boulevard S40. When I got the pads off, I couldn’t push the piston back in, so I pressed the brake lever to just push the piston out. I cleaned the piston and put it back in but this basically left bunch of air inside the system. I did the standard bleeding procedure a bunch of times with no luck. The brake lever just wasnt generating pressure. I’ve realized the trick is not to pump the lever fast. Just do slow pumps and the air bubbles pop up on the main reservoir just like on this video. Repeat the process slowly. This solved my problem. Didnt even need to bleed from the bleed valve. Pumping slowly just bleeds all the air from the top.

[@MotoMirius]

Great job and thanks!

[@dylanreynolds4899]

Mine is completely empty because its a all new system so how do i get the fluid from the resovoir to the lines and caliper?

[@MotoMirius]

You just fill the reservoir and it will flow down into the system. If you have ABS or other poor design elements then you may need to pump the fluid into the system/

[@ArcanePath360]

Nice tip. I've always wondered about the rubber membrane that goes back. If it's pulled down out of shape should I push it back into it's proper shape before putting back?

[@MotoMirius]

Only if you’ve put new pads in. The membrane is to take up the space as the fluid level drops. It drops as the pads wear and the calipers hold more fluid and shouldn’t be topped up on a bike. But don’t worry overmuch if you do! Skäl. David

[@ArcanePath360]

@@MotoMirius Thanks very much for explaining. I did reset them. I guess when I eventually put new pads in (plenty of life on these), do I undo the cap and let the pressure release as I push the pistons in? I'm guessing it might invert the membrane if I don't? I also found fluid on top of the seals which I think was water, so perhaps they need flushing anyway (the book says to replace every 2 years).

[@MotoMirius]

@@ArcanePath360 Undoing the cap will make the pistons easier to push in. Be careful if you have topped it up as the master cylinder can overflow and DOT4 will strip any paint it comes in contact with. Yes, brake fluid should be changed as a standard part of your service intervals, normally every two years.

[@ArcanePath360]

@@MotoMirius Thanks.

[@POLOAZTECA]

Hi. Need a lil help here! I got a 05 650. No brakes so I did all new calipers. Still no brakes. Just replaced master cylinder still no lock. Handle still don't seem to be doing much. Pretty lose goes all the way in! Any ideas what it might be? Thanks

[@MotoMirius]

First guess always goes to air. If you have the stock loop over the front wheel, it probably contains air.

[@ytar-_-8127]

Hello, i have a question. Few days ago I fell on my Honda pcx and after that fall I have resistance on my front wheel. My friend told me that, i just have to put the air out from braking system, but I am not sure. Can you help me or someone what is wrong with my bike? Thx

[@MotoMirius]

Air in the system will make the brakes soft at the lever, and a fall shouldn't introduce air into the system unless something is broken. Check for damage to the brake unit on the wheel and around the wheel/ mudguard as this may give a clue to the issue. Otherwise sometimes the wheel will twist - the solution is normally to loosen the front axle nut, bounce the front suspension so that the forks reset, the retighten the front axle. Good luck.

[@Kush.46]

Hey David, Just wanted to know that how long do steel braided lines last before we need to replace them. And can old brake hoses be a reason for spongy brakes? Btw my brake lines are about 8 years old. Looking forward to hear your say on this.

[@MotoMirius]

Braided lines certainly have a longer life - not seen anyone quote a lifespan on them - but they have a liner so they will have a life. Braided lines are less prone to creating spongy brakes because that is a main purpose of the steel braiding - old OEM rubber lines are a common cause of spongy brakes where the wall loses integrity.

[@Kush.46]

@@MotoMirius Thank you for you feedback. I fixed my spongy brakes. The culprit was the caliper. Once I had used gas welding to open the bleeder screw as it was jammed and yesterday I noticed that there was fluid leaking from the bleeder screw. Just swapped the caliper and the brakes are working just fine now. Thank you for sharing your wisdom with us🙌

[@Kush.46]

I wanted to check one more thing with you. So I have a Duke 390 and the front sprocket has been making some kind of weird noise when the bike is decelerating. Even changed the chain and sprockets but the noise still persists. So can it be because of a bad output shaft bearing which sits behind the output shaft oil seal?

[@MotoMirius]

@@Kush.46 It could but then you should able to hear and feel that if you rotate the output shaft with chain removed.

[@marcteleki2801]

My break locks sometimes is due it has air in the system thanks if you can help

[@MotoMirius]

Air will make the brake lever soft. It will not make the system lock up. The brakes sticking on normally indicates that the callipers need cleaning or service.

[@wildwindwoman]

Why would I have break while bike is sitting but none while bike is moving. We have bled the break numerous times with same results.thank you

[@MotoMirius]

There is no logical reason with a working system. I would guess that there is a mechanical issue which occurs with the vibration of a moving bike. Check to make sure you are not losing brake fluid when riding. Potentially there is an issue with the master cylinder or seals on the caliper pistons. I currently have an issue with a bike where it does not maintain pressure if the bike sits for a period and I suspect it is losing fluid but I have yet to find the leak so it may be leaking back past the master cylinder seal - next step for me is to inspect the calipers for leakage and then a master cylinder rebuild.

[@edgardomatos6923]

Gonna try it tomorrow, my front brake is hard , and not stopping. 86 goldwing, 1200A, aspencade .... Thanks for making the video

[@MotoMirius]

If the brake is hard but little braking is happening then I'd first make sure that the pistons are free in the calipers. When were they last cleaned?

[@edgardomatos6923]

@@MotoMirius not long ago replaced the front brakes...

[@MotoMirius]

@@edgardomatos6923 Air makes the brakes soft. If they are stiff to apply then something is seized - most of the time it will be the pistons. It could be the master cylinder, but this is less common, or perhaps the brake hose is pinched somewhere?

[@edgardomatos6923]

@@MotoMirius more like soft ...but no firm stop when apply. .

[@MotoMirius]

@@edgardomatos6923 Three common possibilities - old rubber hoses (3 year service replacement for most manufacturers), air or old fluid.

[@Ausblack]

Best tip for pushing the pistons back in is to open the brake bleeder, it stops fluid pushing back into your reservoir and makes it easier pushing the pistons in.

[@MotoMirius]

Sounds a good tip for when those pistons are stiff

[@edgardomatos6923]

Opened resevoir, squeezed the front brake ...no bubbles .. piston caliper is free . Guess im gonna have to crack at the bottom , see if air comes out

[@MotoMirius]

Gravity bleeding requires a clear path up from the calipers to the master cylinder. If there are any downhill sections then you need to change that. Good luck

[@edgardomatos6923]

@@MotoMirius thank you ...much better ...alot of little bubbles came out ....so i let the bubbles air out , till i seen the tube solid , bubble free ....brake works much better ....

[@MotoMirius]

@@edgardomatos6923 Great job, well done!

[@bokendrick6553]

I've done all he recommends and i still have no resistance on lever. Been working on it for hours. No leaks in system anywhere. Thanks

[@MotoMirius]

Do you have loops in the brake line - over front wheel, ABS etc? Air rises to the top, it doesn't like going downhill so the brake fluid will slip past it leaving an air bubble at the high point.

[@bokendrick6553]

@@MotoMirius no loops, no humps. Hydraulic line leaves master cylinder and down to caliper. My caliper is not mounted but all connected to allow more straight hydraulic line. No leaks. Still bubbles no resistance. I tap on line, i can literally shake caliper lo loosen bubbles. I topped off caliper with fluid. Still bubbles, no resistance. I'm looking to connect all back up and ride. I have new rear brakes. May road vibration will help. This is craziest thing I've dealt with it over 50+ years working on my own motorcycle and scooters. Oh well... thanks for helping.

[@MotoMirius]

@@bokendrick6553 If it isn't bleeding, maybe the issue is the master cylinder?

[@bccapone837]

Literally did this yesterday and it popped up in my KZbin this morning 🤔👍🏼

[@MotoMirius]

Ha! Legend!

[@justaguy4real]

2:30 what if there's a loop in the line, esp from rear brake?

[@MotoMirius]

Remove the caliper to eliminate the loop, especially with twin front brakes. I don't use this on the rear brake because it's generally too flat for the air to move well. Fill the master cylinder, leave cap off, open rear bleeder, pump the rear brake until the master is getting low, close the rear bleeder. Repeat 3 or 4 times, normally works fine.

[@justaguy4real]

@@MotoMirius how about if i just have someone keep the matter cylinder filled pouring more when needed? Just keep pumping until fresh comes out, then close the valve?? How about reverse bleed?

[@MotoMirius]

@@justaguy4real You could have someone do that, but it would take longer to arrange than the couple of minutes it takes to do it yourself. Reverse bleeding works but again more messing about. Do it the way you prefer and you won't know that until you've tried different methods.

[@79sketches]

I have tried this approach but when I squeeze the lever there is no bubbles but also the brake continues to feel spongee

[@MotoMirius]

The process relies on having an upward path from the brake caliper to the master cylinder for the air to rise up along - which is how the brake engineers designed the brake system to work. But if you have air traps in your brake lines - loop over front wheel brake line or ABS for example then you will have a section of the brake line with a bubble in it which creates the spongy feeling. An alternate issue is if you are still running old stock rubber brake lines - these are supposed to be replaced as part of the service cycle as the brake line walls soften and expand under pressure which also creates a spongy feeling as you are blowing up a balloon instead of moving the brake pads - and why they are typically no longer fitted to new bikes.

[@79sketches]

@@MotoMirius the master cylinder was level the first days but then I inclined a bit to have the holes in the reseevoir be even higher. And still nothing. Also i check for leaks on all the system and nothing. As an extra note. This happened just after I cleaned the front caliper (unmounted and mounted again) and suddenly the brakes were like that. My line is from the metal ones. Forgot the name of it

[@MotoMirius]

The process relies to basic physics so there is no reason for it not to work. If you say the issue happened suddenly after removing and refitting the caliper then it suggests that the issue is there. I would inspect the caliper and especially line carefully to make sure it did not get twisted or crushed and follows the same routing. Good luck with the diagnosis@@79sketches

[@79sketches]

@@MotoMirius lets hope! Thanks for your replies. I just hope is not a faulty cylinder

[@steadyeddie7453]

The air vent on the cap of a master cylinder is not to allow air to escape out of the system (1:20). Hydraulic brake systems are completely sealed. The cap has a hole to allow the rubber diaphram seal under the cap to be drawn down as the brake pads wear and the fluid level in the M/C drops. And ALWAYS bleed the brakes after opening the system, period. Brakes are not an option. Don't gamble with brake work.

[@MotoMirius]

You were doing so well, until you weren't. I recommend keeping to the punchy point and then stop there. The delete key is your friend.

[@jamesXely]

If I leave the lever tied back over night, will there be a major advantage having the cap off or will cap being on let enough air out to notice a difference overnight?

[@MotoMirius]

No real advantage in leaving the cap off but it will expose the fluid to air and if DOT 4 allow it to absorb water.

[@nathanwilliams4179]

Does the same apply to the rear brakes? Can I just keep pumping and bleed air

[@MotoMirius]

Depends if you have ABS or not. If you have ABS then no, because the line immediately runs uphill to the ABS pump. If no ABS then yes it can if you drop the brake caliper off and rest it on the ground to create an uphill path. But my recommended process in that situation is to fill the rear master cylinder, leave the top off, fit the drain tube to the rear bleed screw, crack open the bleed screw and leave open, quickly pump the rear brake lever until the rear master gets low, close the rear bleed screw, refill the master cylinder and repeat say three or four times. Takes about five minutes from start to finish (because you aren't constantly opening and closing the bleed screw) and normally works well.

[@stephanlokkee]

Hi..nice video.i bought a new of caliper and lever..i tried bleeding it for 30 minutes and i still have air coming..i stopped for today..what is your advise please..thanks mate..keep it up🎉

[@MotoMirius]

Thanks. It can take a while, and some systems are just full of air traps - but check you've no fluid leaks anywhere - leave it overnight with the lever pulled in and see if it's the same the next day. And good luck with that.

[@stephanlokkee]

@@MotoMirius ok thks dude..no leak..working on it now..pumping..will let you know

[@christiantorres5282]

I have a chiniece quad and i didnt have any pressure in the rear breaks i keep on doing the bleed but air still wont stop coming iut of the little valve

[@MotoMirius]

If it continues to have air in and you are bleeding properly then there is a leak in the system - or you are are allowing the fluid to drop too low in the reservoir and you are introducing more air into the system. Skäl David

[@mckav2358]

Hi David Ive never bled brakes b4 & have been searching the internet for 'how to' bleed brakes. This method is amazingly simple. I have a set of braided brake lines to replace the rubber ones. I will give this ago. Tell me when you leave the brake lever pulled on over night to purge any air, do you leave the master cylinder cover off or attached ? Thanks

[@MotoMirius]

Hi, the method is simple but as with anything to do with brakes, execution can be more complex depending on the bike - such as loop over the front wheel, splitters etc (all things I remove when replacing brake lines - and banned on many track days because of the issues they can cause) and ABS. No need to leave the master cylinder cover off as it has air bleeds to allow the flow of air in and out - otherwise when using the brakes you'd be causing a vacuum inside the master cylinder every time fluid was pushed out into the lines to activate the brakes. Good luck! Skäl David

[@mrace1180]

Im able to build some preassure in the rear brake, out after literally thousands of pumps, it doesn't seem to get any better. I think there might be a leak in the master cylinder. Any tips?

[@MotoMirius]

Assuming you have the correct amount of fluid and no leaks then failure to build pressure suggests a faulty master cylinder. Replace.

[@mrace1180]

@@MotoMirius As I said, I am able to build a little bit of preassure, the brake works slightly. I bleed the break, and the preassure does not seem to rise. I Pumped over a thousand times (literally), for 20 minutes straight, still coming bubbles, and still a slight preassure, but does not seem to rise. Maybe keep pumping?

[@MotoMirius]

@@mrace1180 As I said if the pressure does not happen and you have no leaks in the system, either you are not bleeding it properly or your master cylinder has failed.

[@zokonjazokonja]

I bought complete new handle bar with master cylinder, but I think that something is wrong with cylinder. I perform air bleeding (conventional way and reverse), I don't think that air remain in system, but breaking force is just too weak, brake pads move just small amount, and there is almost no back pressure on lever. What is strange to me is when I press handle bar, there is significant oil shooting in reservoir from smaller hole, in your video I do not see oil shooting out of reservoir, only some air. Is this normal that oil shoot during pressing?

[@MotoMirius]

The oil shooting out is the oil returning back into the cylinder after being pushed down the line by the master cylinder. It's normal when there is some pressure in the system. You won't see it in my video because I am controlling the lever return so it doesn't happen. If the pads aren't moving and there is no pressure on the lever the the oil is not reaching the pads. Most likely causes are master cylinder needs rebuilding or there is still air in the line. Connect your old master cylinder onto the line, air bleed the air that got in when you did that (it will only leak a little oil from the very top of the line) and see if the problem still exists. Good luck. Skäl David

[@zokonjazokonja]

@@MotoMirius Thanks for very fast respond. In my case oil shotting is hapening during lever pressing, not releasing. Brake pads move, and I have some weak force of braking action, but force on brake lewer is totaly low. I have some video of this oil shooting www.dropbox.com/s/rzx7981kwfuir1z/VID_20200922_182314.mp4?dl=0

[@MotoMirius]

@@zokonjazokonja Oil shooting is normal. This is not your problem.

[@zokonjazokonja]

@@MotoMirius OK, thanks

[@MotoMirius]

@@zokonjazokonja connect up the old master cylinder (you don't have to attach it to the handlebar) and see if the problem goes away as I suggested before. It will tell you if the problem is in the master cylinder - it's new and untested so a likely issue. If it is the problem then get a rebuild kit or use your old one.

[@luckyhah]

Hi David, when I do this with cap off the brake fluid squirts out.. does that indicate any sort of problems..? With cap on when I squeeze the lever I hear a hizzing sound and the initial bite is soft, only becomes firm from the middle of the travel. I've bled the system and the feel is the same. Hope you can help..!

[@luckyhah]

The hizzing sound is likely from brake fluid squirting inside, making a turbulence inside the reservoir

[@MotoMirius]

In the video I warn against releasing the lever too quickly. If you do this the liquid can squirt up. If the bite is soft then the two most common reasons are air still in the system or you have old rubber type hoses. Skäl David

[@jamesnorth7318]

When you have the laver tied overnight do you leave the cap off?

[@MotoMirius]

No - you can but especially if you are using DOT4 that is just asking for water absorption into the fluid which will give you soft brakes

[@adamstyles823]

Worked on my 125 duke after removing front wheel for bearings clean

[@MotoMirius]

That is awesome!

[@bearsgarage272]

Wish i saw this sooner. Just upgraded to stainless braided lines on my Honda and bled them the hard way

[@MotoMirius]

Always next time!

[@sanesaint8725]

I drained all mine and I tightened it back up and then I just put a little bit in wouldn't work came back a week later did not crack it at all on the bottom put some in just started pumping it easy and I seen air bubbles coming up I was done in about 3 minutes first time I did it wrong I guess

[@MotoMirius]

It sometimes takes a bit to get the feel of this method and find the best way to work it for you.

[@martbful]

Does this work the same on the rear brake?

[@MotoMirius]

It can but you have to remove the brake unit so that there is an uphill slope for the air to rise up. Generally the rear brake doesn't present any issues for normal bleeding.

[@jamesbronson3347]

Will this work on rear brakes where the caliper and reservoir are almost horizontal? Thanks

[@MotoMirius]

No, though you can make it work by removing the rear brake and lowering it. For rear brakes I recommend filling the rear master cylinder, opening the bleed, fast pump the full contents of the master cylinder, close the bleed (no opening and closing at each pump) repeat x3. Do not allow the master cylinder to fully empty or you will push air in. ABS makes this harder.

[@lukasgarage956]

I tried every possible way to get rid of a spongy brake.....traditional bleed, gravity bleed, reverse bled, handle tied overnight, new master cylinder, caliper rebuild.....brake hose was bad, it would expand with pressure.

[@MotoMirius]

Brake lines are a service replacement item for that very reason and why braided hoses are more common now. Sounds like someone skipped the brake hose replacement part of the service probably more than once!

[@lukasgarage956]

@@MotoMirius bikes a 95 Ducati, probably the original hose......all good now.

[@VonAndreAcabal]

I realize I was doing this before and it really works. But now I have a question, why does the cap need to be removed? Won’t the bubbles come out if we squeeze/tap the lever with the cap on?

[@MotoMirius]

Cap doesn't have to come off, the engineers designed this to work with the cap on - but it's easier to judge by the bubbles where you are in the process. If I've had to remove the brake hose from the master cylinder for example and lost a little fluid in the process I won't take the cap off because it only takes a few presses of the lever to work that air back into the master cylinder.

[@SuperDjfudge]

I've just changed my levers and my front brake reservoir and I've got no front braking will this way work at all

[@MotoMirius]

Yes it will - assuming there are no issues with what you've done. If you want to see it done by the Master then watch this video - previous videos show full overhaul of caliper and master cylinder so it's a fully dry system with no brake fluid in it. kzbin.info/www/bejne/o4eZYXigjZyLeNk

[@shujabhatti536]

Hello sir i need your help again, i have a bandit 250 and i cleaned its carbureators and it started overflowing to which i adjusted the float level and the the overflpwing stopped BUT my bike doesnot wants to stay at idle and it gets turned off and also when i remove the carbureators i see a lot of raw gas on the rubber housings, going into the engine, do u think this could happen if i switched the places of the small and big fuel jet?

[@MotoMirius]

Jets are normally different sizes, can't comment on the Bandit 250 but the jet sizes are written on them so you can easily check. I think it's more likely you have an assembly error. You would adjust the float levels if they were wrong, but if they were not overflowing before you took them apart I would suspect the needle wasn't seated when you put it back together. You might want to double check that the float levels are correct.

[@michaelmillar845]

Thank you so much for this video Any Idea if it will work on a 2015KTM Duke 125 with abs

[@MotoMirius]

Not with ABS because the routing of the brake lines to the ABS unit creates air traps.

[@michaelmillar845]

Ahhhh thanks for your reply, currently when I take the cap off the reservoir on the handle bars I get big bubble when I pull the brakes. I guess I will need to get the system bled?

[@MotoMirius]

@@michaelmillar845 You should still be able to bleed it the normal ways - reverse bleeding or bleeding by building pressure with the lever and opening the bleed valve - but it can take time. Dealers use pressure bleeders - but this is because they charge for their time and no dealer wants to explain to an angry customer why it took two hours to bleed the brakes.

[@Tyler.i.81]

Would the same work with the back beak

[@MotoMirius]

Back brake lines tend to be flat so air isn't able to rise - tends also to have air traps where the line dips so no. Instead, take top off master cylinder and top off. Open bleeder then continuously pump the brake lever until the master cylinder runs low, close the bleeder, refill the master cylinder. Repeat 2 or 3 times. Refill master cylinder to correct level and refit cap.

[@sanesaint8725]

That's right once you crack that bottom nipple air is getting in only crack that bottom one if you got to get rid of some dirty brake fluid

[@rosegold-beats]

Mine just doesn't get hard, and when i bleed i see no bubble and i also see 0 leaks

[@MotoMirius]

You'll need to give me a lot more detail about the setup than that. A lot of modern bikes have compromised brake designs - ABS, loop over front wheel because they care more about looks than braking etc. If your brakeline layout has air traps then this system isn't going to work.

[@ed5311]

Great idea! Very well explained. I'll try that. Merci beaucoup !

[@MotoMirius]

Good luck with that!

[@jahlion9488]

Thank you so much sir... Your information helped me answer some school questions

[@MotoMirius]

Most welcome

[@Reeseybaby]

Does this same method work with the rear brakes cause no matter what I do it's still spongy even after buying the speed bleed and installing it.

[@MotoMirius]

This method relies on air travelling up and fluid travelling down. This is not the case in rear brakes nor in any system that includes ABS. With non ABS I normally top up the reservoir, open the bleed, pump the fluid fast till the reservoir is nearly empty, close the bleed, refill reservoir and repeat a couple of times - do not open and close in the bleed during the pumping. Typically this will flush any air. It is possible to use this method if you dismount the caliper and arrange the line so there is an uphill flow to the reservoir.

[@Reeseybaby]

@@MotoMirius ok thanks a lot

[@maverickevans5362]

Will this work for a vfr800fi rear brake line?

[@MotoMirius]

Rear brake lines tend to be horizontal not vertical so the air can't flow up to the master cylinder. In addition if you've got ABS there is an air trap that can't be overcome by this method as the ABS unit tends to be higher than the rear brake unit. I would tend to recommend a flush instead - fill the reservoir, open the rear bleed screw, pump the brake lever until the reservoir is nearly empty. Close the rear bleed screw, refill and repeat four or five times (more if it is a tiny reservoir). Do not open and close the bleed screw as you pump. Do NOT let the reservoir go empty as you will introduce air. Good luck!

[@rogercrier9115]

Ive never been able to grasp in my head how when a car is made, it has no fluid in the system at all. It gets its master cylinder reservoir connected to a machine that sucks all the air out, so all the pipes and slave cylinders are a vacuum. They then have the machine release the brake fluid into the master cylinder tank, and the fluid fills the entire system, with no bubbles. They also do this when filling the coolant system with antifreeze, and when the vacuum is applied, all the rubber hoses squash down flat!!! Amazing, quick, and no pissing about with bleed nipples and bits of tubing✅

[@MotoMirius]

Nearly all dealers do the same for fluid changes - it's nearly always sucked in by a vacuum pump as the pumps removes all the old fluids as it sucks in the new. Sometimes it will be pumped, but the effect is the same, but these changes were not because they wanted to invest into facny machinery, it's necessary because of all the add on devices such as ABS which create air traps.

[@antonbende8210]

Yes good info for the first timers... hehe.. just an extra hint, run your engine a bit,... the vibration will help the air fly up faster !! take it out of the gear !! haha

[@MotoMirius]

Vibration is always useful. Great tip 👍. Skäl. David

[@motoryzen]

BEGINS at 3:57

[@MotoMirius]

If you want to skip all the background about why.

[@motoryzen]

@@MotoMirius because some people actually want to get to the point.of something. It's not rocket science

[@MotoMirius]

​@@motoryzen Some people yes - but only if you know what you are doing. If it's your first time and most who are reaching out to videos have never done it before - then it is rocket science - you are looking through the tiny lens of your own position - as a creator I have to consider that most who watch don't have that background or the context.

[@bryanlettow4389]

So I’ve bled my brakes the normal way by pushing the air out of the valves but my front brake still has no pressure in the lever. What should I do? I’ve now put a zip tie over the lever to keep it in over night with the master cylinder cap off to hopefully rid air that way.

[@MotoMirius]

Did it have pressure before you bled it? Did you do anything else but bleed it? Do you have ABS or a loop over the front wheel? Skäl David

[@bryanlettow4389]

No pressure before I bled it, it's an '85 ninja I don't believe it has ABS. I'm bleeding the brakes because I installed new seals and pistons in my calipers.

[@bryanlettow4389]

@@MotoMirius No loop.

[@MotoMirius]

OK, 85 is unlikely to have ABS. Bleeding brakes is simple, but you have to do it right. If you have no pressure then you are probably overlooking something basic. Brake pressure should be the same as before. Check if the brake pistons are moving and check for leaks. Follow the line down from the master cylinder and bleed the line that is furthest away from where it enters the splitter first.

[@phillipeaton7543]

Hey David, great video. Iv had alot of trouble with a garage recently and them doing front brake work for me. Even though it's stopping if pulled hard, I'm convinced there's still air in the system somewhere as if I pump the lever several times the lever feels firmer than not.

[@MotoMirius]

Hi Phillip, if the lever gets firmer then it does indicate that there is air in there. Air can be hard to get out of some systems because poor design by the manufacturer of the vehicle can create air pockets. Lines that wrap over the front wheel of bikes are a great example of this and ABS almost always means piping going the wrong way for good bleeding. Skäl. David

[@phillipeaton7543]

@@MotoMirius yeah o do have ABS as well, is there anything else I should do have abs?

[@MotoMirius]

Phillip Eaton it’s just a question of getting the lines bled properly. It’s why I like to do it myself. When garages are under time pressure because the bill is getting too big they can take short cuts. Sometimes you need a pressure or vacuum bleeder. David

[@chadwickciampo3634]

Thank you so much! This help me finally bleed my brakes. And learned a good lesson! Awesome!

[@MotoMirius]

Glad it helped and good on you!

[@foxtrottango8745]

Good information. I like the way you did this because I use to bleed out the air by pumping the brake lever then cracking open the top hose bolt letting air out then quickly tighten it up... and start the process over again until the air was out. This is a s so much faster. Thanks again. 👍😎👍

[@MotoMirius]

Glad it worked for you. There are times you need to bleed fully but this does the trick most of the time.

[@vquizxckwy]

Hi Sir David, Im having a problem with my front brakes.. While I am cleaning my front calipers double piston, the one piston accidentaly got off in the calipers then the brake fluid came out.. I dont have a choice but to clean it then put it back on but the other piston I didnt clean it... Btw im using Racing Boy Double piston caliper for my yamaha x1r. Moving over. It seems that my brake fluid is dirty somewhat brown color. I think I need to flush it out 1st am I correct before doing this method? . I also watched the linked you comment in the harley bike.. I like that method thats the same as this video right? My brakes is working sometimes if i press my lever fast but if i press my lever slow, Its so soft like no pressure or no brake. then sometimes its in the middle range if i press it normal.. I hope you answer my question.. Thank You

[@MotoMirius]

Brake fluid is typically changed every two years, especially if you are using DOT4 because this absorbs water, so when it discolours then it's time to change it out for some fresh fluid. It's not a big deal if a piston comes out - as you found, you just put it back in and normally add a little more fluid into the system. The lever should work all the time, fast or slow - so I think it's time to change the fluid and get rid of the water and air that are in the system. Good luck

[@vquizxckwy]

@@MotoMirius thank you sir.. I changed the fluid now and i use your video... It wored thank you.. But now the problem is. My bleeding screw.. Even it is locked fluid comes out. Is it ok if i jam it with something.. Or disablr it. Forever?.. Should i use steel epoxy to jam. It?

[@MotoMirius]

@@vquizxckwy If it's leaking then there is dirt or damage to the cone seal at the bottom of the seal. Remove the calliper and raise it above the master cylinder to prevent leaks then remove the screw and inspect it and the bottom of the hole it screws into (the threads do not provide the seal) If it sealed before then it should seal now so it most likely is dirt. Replace the screw if necessary, don't seal it.

[@vquizxckwy]

@@MotoMirius ok ill. Check it out.. Thank you for you response and help.. 💚💚

[@peterstamiris1358]

Im rebuilding my calipers and was wondering xan ibuse this method to bleed when im done reinstalling them?

[@MotoMirius]

Yes - so long as it's the front calipers. If you have an over the mudguard brake line or other such loop then you will need to arrange the calipers to allow air to rise through the brake hose. I always do mine this way.

[@peterstamiris1358]

If I understand this method only works if brake line has no loops in it?

[@MotoMirius]

Air rises in liquid. This is how the engineers who designed the brake system intended it to work - so the system self bleeds. Bike designers aren't always engineers. I understand some tracks ban bikes that have front brakes that loop over the front wheel because of the risk of brake failure. Even with this setup you can make it work simply by removing the second caliper and sitting it on the ground under the first caliper so there is an upwards path - I used to do this, but now I just replace the lines so they run straight to the master cylinder. Of course ABS is also an issue.@@peterstamiris1358

[@peterstamiris1358]

To help you understand and visualize my brake line goes down to a splitter and has a cable on each side going to there respective calipers, i assume I could still use this method cause the air would still be able to come up regardless of splitter right?

[@MotoMirius]

absolutely yes, that setup is fine.@@peterstamiris1358

[@zep0th370]

So basically, all I need to do is remove the cap and just press and release the pedal until the bubbles stop?

[@MotoMirius]

Yes. This assumes that there is a clear upward path for the air to flow up. If you have loops then you have to figure out a way round those. Skäl. David

[@jacobgeuss9086]

What about the back breaks is it the same

[@MotoMirius]

It can be, but typically you just need to flush them through by pumping the lever until the reservoir gets close to empty, closing the bleeder, refilling and repeating a few times.

[@walloham1018]

so what do you gotta do after u tie up the lever overnight? do u have to open up the cap again?

[@MotoMirius]

The only reason you ever need to open the cap is to add more fluid. If the lever is still soft then you've still got air in the system or you have a different problem with the system such as old rubber hoses - these expand under pressure (which is why they are supposed to be replaced - normally every 4 years) and so will make it impossible to get a firm lever.

[@walloham1018]

So after tying up the levers, the air would be purged out of the system? I just recently changed to a steel braided hose but i guess it would be my brake masterpump causing it to be soft am i right?

[@MotoMirius]

The air will only purge if it has a clear route upwards. Some bikes have design issues which make this not happen such as ABS and loops over the front wheel. ABS will often require pumping through. Air traps such as loops can be dealt with by taking the callipers off. Or you may need to rebuild the master cylinder.

[@walloham1018]

I see. Thanks for your help sir i understand better now