Shimano Deore XT M8000 Brake Lever Master Cylinder Rebuild & Disassembly

Sadly the camera was on ISO 6000 so the quality rather noisy.
This lever originally had the same issues that you see on the SRAM Guide levers where the piston expanded and seized.
Same solution, just sand the piston diameter down.
00:00 Disassembly
04:10 rebuild

[@leosberk]

Thanks for the great video. The procedure was less time consuming than I thought. My only hang up was where I was trying to position the spring in reassembly. When I rewatced the video, I see that you clearly show where it should go. Also, it helped to just reference my other brake lever...

[@felipef.p3047]

You have to do with no fluid on the system, so you can push the lever all way to the end, as you see the man on the video..then insert half of the pin, put the spring and finally insert the rest of pin on the lever

[@polishguywithhardtospellna8227]

And i thought i found out the easiest technique of getting the plunger out. Your technique is far better.

[@armanrivera4116]

thanks! helped me a lot to repair my m8000.

[@ShreddingSpree]

This video helped me. Thanks!

[@a8f235]

I got the M8100, but it's pretty much identical. Both my levers started squeaking so was good to watch a bit of this video. I only removed the lever and the plunger mechanism. Then just cleaned everything with q-tip and isopropyl alcohol. Then I lubed up the bearing and shaft of the plunger and reassembled it. I also lubed the pin that goes straight through the lever and holds it in place. I also applied a very thin coat on the contact point of the lever that will be touching the bearing. Just super thin coat. Everything is now squeaky free and I can rest easy again. I will be more careful when I wash my bike from now on. Even though it's no pressure washer, the cleaning has definitely started the squeaking so I'll just rather use a towel and just wipe muck/grime off that area from now on.

[@Chambers36TheEnter]

Sounds like you did a proper job of it. I think just wiping the muck off seems like a good idea. I think some people would be tempted to use gft85 or wd40 which would just strip the components of any grease and make things worse.

[@a8f235]

@@Chambers36TheEnter I did start off thinking of using a spray to not have to disassemble anything, but the disassembly was super easy so it's no point not doing it. Using any kind of spray lubricant I thought as well would just make things worse and in a short time would most likely make more grit and grime stick to it. I would never use WD40 though because I do know it's more of a degreaser than a lubricant. I did not find any maintenance fix for my problem, so I just tried to do what seemed most likely to fix it with the awareness that I might take it apart again. Thankfully it worked first try, so I know what to do next time it happens again.

[@raeesstemmet9656]

Thanks for the very informative video. I think next time just get better lighting. The video is a bit dark and we cant really see into detail. Keep up the good work.

[@roweldagooc2651]

Thanks for the vid man!

[@Chambers36TheEnter]

You're welcome. Glad it is of use to some people.

[@albertgossen1]

Sehr starke Anleitung. Die Position der Feder beim wieder einbauen etwas genauer wäre super aber ansonsten echt mega hilfreich. Das ganze geht auch alleine, aber ist auf jeden Fall beim ersten Mal nervenaufreibend. Habe für den ersten Hebel 2 Stunden gebraucht und für den 2. 20 Minuten. (Inklusive reinigen schmieren etc)

[@onedsf]

Excellent breakdown and reassembly tutorial. The camera angle and focus made it a little challenging to follow a few parts of the reassembling, but there's enough here to provide a sufficient guide and provide some confidence in working on this unit. Are the internal plastic parts replaceable if they break? I've been looking to see if I can source spares as an "in case". Thanks again for putting this together.

[@Chambers36TheEnter]

Hi Thanks for the input, I agree it could be filmed better but I am limited for space. As for spares, I do not think there are many official shimano spares for the internals but I believe you can find piston seals and maybe a few other bits on ebay from China as aftermarket spares. It's silly that shimano expect you to buy a new lever for the sake of a £5 rubber seal.

[@Ty-sm9cv]

@@Chambers36TheEnter The plastic guides do break unfortunately, and Shamano doesn't sell replacements. People have designed replacements though, and you can buy the top/bottom for the left or right for around $20 for the set, so you can rebuild these for about half the price... That being said, Shamano not offering these parts is criminal.

[@flybuster]

thanks for this great video. Question: is this tutorial applicable to XTR BL-M987 ? i plan to replace the brake lever cylinder..which is leaking

[@Chambers36TheEnter]

Thanks. Yes I would say that this video would be some help with regards to the XTR M987. I often see people talk about leaks on the Shimano stuff and seems to be right at the end where there's a circular black cap, sometimes gold. Not sure if it is leaking from there if it's repairable.

[@semeolvidoabc123]

Great video, very helpful. I recently broke the left/front levar no my xt 8100 brakes. I was able to find the actual lever on Amazon but it says right. Since it is just the lever and it seems symmetrical, do you know if it would work on the left break? Thanks for your help.

[@Chambers36TheEnter]

I'm not too sure without looking at the brake but I don't have any m8000 brakes here to check. The left lever blade is part number Y2RR98020 for the 8100 if that's any use. Good luck.

[@mattfaunt]

Thanks for the great video! I have experienced this same issue (expanded/seized piston) and currently have my lever disassembled following your instruction. I've seen replacement Titanium RISK pistons via AliExpress, but would prefer not to wait 3 months for delivery. Can you offer any tips on sanding down the plastic pistons? What grit sandpaper? I assume you remove the rubber seals? How do you know when to stop sanding?

[@Chambers36TheEnter]

I would remove the piston seals as they are easy to damage if you did touch them with sand paper. Try to stretch the seals as little as possible when removing them, f they are really old they could be weak and snap. Sand paper I don't remember, something like 600-1000 grit sounds good as the nylon is easy to sand and removal material. I held the sand paper on the piston and spun the piston around hoping that way it would keep it nice and round rather than taking off more material on one side. I stopped sanding when there was no scratches left in the piston, your piston might now have scratches but you can just sand, then drop the piston into the bore of the brake and make sure it's free to move.

[@Jon-ty6bb]

I was hoping to see how the reservoir could be accessed as it differs to previous XT brake leavers.

[@matoatlantis]

Thanks for the video. It seems my lever doesn’t have a grab screw. I not sure if I can proceed with the main pivot removal. Not sure if I’m missing something or if there was an update on the lever over the time.

[@Chambers36TheEnter]

I don't know if they updated this specific model, I do know they do a M8100 lever which is different. Sometimes the grub screw is covered by a rubber plug.

[@matoatlantis]

@@Chambers36TheEnter That was a problem. The rubber plug was so nice and snug in there it seemed like a part of the lever. Good that I didn't proceed and kept looking for this grub screw. I saw your comment just after I figured that out. :-) I guess "power of asking" in action, I was trying to figure this out yesterday without luck. Again thanks for the video, it does help a lot to see where one needs to use more brain and when small force is ok (I had to carefully hammer out the pivot).

[@therewolf184]

There are vendors on AliExpress that now sell replacement seals and pistons made from Titanium for Shimano brake levers - just search 'Shimano lever piston' on AliExpress. Have you heard of these, and do you think they'd be a worthwhile investment if tearing down one of these levers due to leaky seals?

[@Chambers36TheEnter]

I have used aftermarket metal pistons for the SRAM guide levers, the plastic ones would swell in the heat and cause them to seize. Never had any issue with the parts, fitment was good. As long as it is really titanium it would be okay as it should not expand too much when it heats up. On E B A Y they do them as well, for about £7 each so for £14 it seems like a good deal.

[@lukasbad5646]

Hello, I see that you know the topic, so I have a question for you that is the essence of the problem on the Polish bicycle forum, there is a big quarrel about it. What is this hole on the side of the lever for? This is the only part in the handle that you have not disassembled, in the lever xtr and probably also in saint this element is yellow, some say that it is a "safety valve" through which excess mineral oil escapes, and some say that there is a membrane and if excess flows out that way oil, this membrane is damaged. Unfortunately, I have no way of adding a photo to show which element it is about, it is the round element that is common in the newer Shimano levers. Thank you and best regards from Poland

[@Chambers36TheEnter]

Hi, This is something I do not know! I rarely work with or use Shimano brakes but most levers will have a way to release pressure and vent fluid if they get over filled. I know exactly the port you mean, XTR levers have gold ones but Shimano don't seem to say what they are there for and don't supply a diagram that I can find to in order to work it out.

[@mtbhillbilly]

Does you lever push outwards abit ive just bought one and mine does isit normal?

[@Chambers36TheEnter]

Hi, the lever blade will push outward, that's part of the reach adjustment mechanism.

[@bankamm3473]

Do you know what size of oring in adjust knob on brake lever?

[@Chambers36TheEnter]

No idea, not really much information on the parts and sizes for shimano stuff.

[@felipef.p3047]

Outra pergunta. Com quantos milimetros gastos já é necessario trocar a pastilha de freio? Uns dizem que 1mm pra baixo já tem q trocar..outros falam 1.2mm.....

[@Chambers36TheEnter]

Eu mudaria em torno de 1mm. Se eles ficarem muito baixos e você não perceber, você pode acabar com metal contra metal, o que pode causar danos à pinça.

[@yt_zam1320]

Can you please help me ? My xtr brake lever Lose oil not on the gasket on the tank

[@Chambers36TheEnter]

It sounds like you have the problem that "LukasBad" was asking about in the comments. I do not have the answer sorry.

[@22Jeffers]

Is this the same as the M785 lever?

[@Chambers36TheEnter]

Hi, yes is pretty much the same process. Shimano haven't changed much since the m615, m675, m785 days.

[@motooilermotooiler9597]

i have difficulty in bleeding my SLX rear brake. did normal and reverse and vacuum brake. caliper properly aligned but for the life of me cannot get rid of this spongy feeling in the lever. the brake cannot be properly modulated with this. I am begginning to think that one of the seals in the lever gave ghost.....

[@Chambers36TheEnter]

If you keep bleeding it but it shows no signs of air bubbles then it can be like you said a lever seal, maybe one of the piston seals is not sealing very well and allowing fluid to bypass, that would give a spongy feeling. Quite a few companies at places like ebay do sell the seals, unofficially and tends to be delivery from China.

[@motooilermotooiler9597]

@@Chambers36TheEnter yup - I sort of lost my faith after the vacuum bleed. Shame I dont have a reserve lever to test it as the tear down will graound the bike for several weeks. I reckon if the outside seal went then it would cause a leak outside. Cannot see it leaking to be honest.

[@Chambers36TheEnter]

@@motooilermotooiler9597 Is there no signs of leaking on the caliper? When I used to work with a lot of the shimano stuff I found the seal on the center of the 2 caliper halves would fail and you could see some bubbles from there.

[@davidpearl6438]

That is exactly the place where I am and I'm thinking. It's in the plunger in the hand lever and I need to replace that rubber seal. Please let me know what you Have found out.

[@ksmoghadam]

appreciate the knowledge transfer but honestly folks that effing spring is nearly impossible to line up with the thru bolt. I wasted a good hour attempting this fix. The thru bolt finally went in, not worth the time and frustration. take it in to your lbs or better yet, shop for new brake levers

[@allanshpeley4284]

There's no way this was recorded in 1080p. I appreciate the effort, but a higher resolution and better lighting would have made a world of difference.

[@Chambers36TheEnter]

It's a Sony A5000, it's not really good for recording stuff but takes okay pictures in the right light. It's an MP4 format recorded at 1080p and also compiled to 1080p. The camera is almost 8 years old so ancient in technology terms. Does need better lighting for sure, my more recent videos came out slightly better. Still new to the editor.

[@allanshpeley4284]

@@Chambers36TheEnter All good. Eventually I figured out the rebuild, but Shimano sure doesn't make it easy.

[@floppywonka]

a straight pin doesn't make this any easier btw