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!

[@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

[@caleblammers6032]

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

[@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!

[@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!

[@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!

[@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

[@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

[@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

[@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

[@WillLinnebur]

This info saved my educational project scooter from being given away after spending hundreds of dollars and hours on it. As I learn more, I see that even my favorite creators leave out important details and cause needless frustration and expense. Every video about bleeding should include this info or a link to it. I laid my caliper on the floor with a spacer between the pads so the air would have a direct path upward. Thank you!

[@MotoMirius]

Very happy that worked for you. Well done!

[@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.

[@mehanicigor6893]

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

[@MotoMirius]

It’s a very old trick!

[@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.

[@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.

[@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

[@bccapone837]

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

[@MotoMirius]

Ha! Legend!

[@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.

[@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.

[@Michaelaharoni]

I am impressed. Great video. I just cleared the air out of my Honda after it was siting idle for a few months and no pressure at all. Thank you

[@MotoMirius]

Great job!

[@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.

[@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!

[@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.

[@KinBDutMean]

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

[@MotoMirius]

Good luck with that.

[@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?

[@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.

[@benardhunt5383]

Thanks Paul, your method works perfectly, short pumps and tapping the brake hose sorted the problem. Thanks for showing this.

[@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

[@smalltowndodge9477]

I knew I was doing it right the first time 🤦‍♂️ thank you for posting this

[@MotoMirius]

Sounds like you know what you are doing! Thanks

[@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

[@chjwood]

at last somebody posted the first steps to removing air from brakes .thanks

[@MotoMirius]

Glad it helped

[@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.

[@adamstyles823]

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

[@MotoMirius]

That is awesome!

[@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.

[@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

[@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!

[@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.

[@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.

[@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

[@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!

[@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.

[@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!

[@JavierEAmaya]

Am restoring a Raptor 660r. I will give it a try. The logic is right. No rocket science. Thanks for confirming that method. By now you would known if it does work or no. So thanks.

[@MotoMirius]

Good luck with this. This is an old technique used for a long time. Not used in service centres nowadays because pressure or vacuum bleeding is faster and that counts when charging a customer by the hour. Faster doesn’t always mean better of course.

[@JavierEAmaya]

@@MotoMirius gotcha. I will let you know how it goes.

[@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

[@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!

[@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.

[@sanesaint8725]

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

[@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.

[@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.

[@daryletoews7099]

Awesome piece of info. Thank you

[@MotoMirius]

Glad it was helpful!

[@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?

[@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.

[@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.

[@evildeed90s]

you fixed my bike thank you

[@MotoMirius]

Great stuff, well done!

[@sanesaint8725]

I just put the drain hose in a circle in the back it must work for the front as well once you see no air bubbles in there bottom hose lock it up wrap the drain holes in a circle and tie it with a twisted side let all the waste fluids go through the circle of the tube when there's no bubbles then you just have to worry about the top works great on the back

[@MotoMirius]

Back just needs some fluid pumping through. It's normally a simple exercise - unless you have ABS, then it can be more painful.

[@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.

[@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.

[@briandemartino2037]

That was insane easy an alot less work and mess thanks man

[@MotoMirius]

Great work!

[@niteshvishwakarma6709]

(TESTED ON ABS BIKE) I have an alternative method, i tie 2 cloths to the brake lever, for holding the brake as tight as possible for a night. The explaination really comes into the play here, the air is pushed up because of steady oil pressure and bubbles flows in upward direction to the Master cylinder.

[@MotoMirius]

I mentioned this method in the video. It's a very common method even with standard bleeding but to get out the very last of the air.

[@niteshvishwakarma6709]

@@MotoMirius Thanks for the reply, i have one more concern, When on hard braking, the lever gets spongy, again i have to repeat the process, any reason why?

[@MotoMirius]

@@niteshvishwakarma6709 Typically there is a leak in the brake lines or the seal in the master or slave cylinder are leaking

[@niteshvishwakarma6709]

@@MotoMirius Thank you soo much! Will diagnose!

[@vicrussell1109]

Thanks for that. worked very well

[@MotoMirius]

Glad it helped

[@KenBritzman]

Excellent work, thank you so much, Wow all these years and i learn this now.

[@MotoMirius]

Thanks, I too wasted a lot of time before I knew this! 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

[@fahadalluhaibi]

Thanks 🌴

[@MotoMirius]

You are welcome

[@andre9377]

It actually worked, Thank you so much 🤘🤘

[@MotoMirius]

Glad that worked for you, well done!

[@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.

[@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.

[@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.

[@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.

[@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.

[@springy-2112]

Hey David always good to see you brother 👍☮❤

[@MotoMirius]

Cheers Springy, long time no see! Skäl

[@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.

[@jonashampshire4714]

It worked! Thank you!

[@MotoMirius]

You're welcome!

[@MrPiero11]

Thank you, I'll try this..

[@MotoMirius]

Good luck with it. Skäl David

[@SpeedDemon92]

Thank you very much for the knowledge !

[@MotoMirius]

Thanks. You are welcome. Skäl. David

[@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.

[@kennethmarler8101]

Worked like a charm 😎 thanks 🙏🏻

[@MotoMirius]

Great to hear!

[@Temetnosce77]

Thank you fella.

[@MotoMirius]

Very welcome

[@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.

[@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.

[@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.

[@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.

[@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.

[@Red-sr7vo]

Saved me thank you so much❤️

[@MotoMirius]

You're welcome!

[@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

[@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

[@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/

[@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

[@brunomagalhaes7933]

Thank you so much.

[@MotoMirius]

You're welcome!

[@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.

[@sreenatha.b165]

Thank you soo much sir it worked..

[@MotoMirius]

Glad to hear it. Well done.

[@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.

[@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.

[@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.

[@tedenduro243]

Tnx man that helps.

[@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.

[@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)