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Broke a piston in my XTR Brake

manhattanprjkt83

Rusty Trombone
Jul 10, 2003
9,644
1,214
Nilbog
Has anyone done this? It was a total idiot move on my part but a bit cracked off and moved the seal so fluid started dripping out. I ordered some 3rd party piston which arrived yesterday. Any tips on the replacement process? This is an XTR 4 piston for reference...Thanks guys...
 

kidwoo

Artisanal Tweet Curator
Has anyone done this? It was a total idiot move on my part but a bit cracked off and moved the seal so fluid started dripping out. I ordered some 3rd party piston which arrived yesterday. Any tips on the replacement process? This is an XTR 4 piston for reference...Thanks guys...
Stick a compressor in the caliper half you're holding to push the piston out.

Don't forget to aim. You'll be amazed at the distance achieved.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
That's the way to go for removal. When you're putting the new ones in, just be really careful to push them in straight and not bugger up the seal. It's not too hard though.
 

jonKranked

Detective Dookie
Nov 10, 2005
85,573
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media blackout
Some weird vendor on amazon, I hope it works...
interesting. i've got 2 sets of xt m785s with the time bomb ceramic pistons. they haven't died yet (we don't have many long or steep descents around here) but they are making me nervous due to age.

will be following to hear your experience on them. which model xtr do you have?
 

manhattanprjkt83

Rusty Trombone
Jul 10, 2003
9,644
1,214
Nilbog
I have the BL-M9120, which are the current 4 piston. Yeah the material these pistons are made from seems more durable almost a polymer type material. I wonder what it will do under heat though...Figure'd I'd try this prior to buying a new caliper. If I wasn't a ham fisted moron we wouldn't be having this discussion.
 

jonKranked

Detective Dookie
Nov 10, 2005
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media blackout
i bet you two ugga dugga'd when you only needed one.

i read somewhere when they launched the new stuff that the pistons are still ceramic, but couldn't find any more detail than that.
 

Da Peach

Outwitted by a rodent
Jul 2, 2002
13,681
4,904
North Van
I have the BL-M9120, which are the current 4 piston. Yeah the material these pistons are made from seems more durable almost a polymer type material. I wonder what it will do under heat though...Figure'd I'd try this prior to buying a new caliper. If I wasn't a ham fisted moron we wouldn't be having this discussion.
I would try for a warranty. XTR, bro.

Mine cracked when I was trying to push them back in during a pad replacement. I got a new brake gratis.
 

manhattanprjkt83

Rusty Trombone
Jul 10, 2003
9,644
1,214
Nilbog
You have a point, I might shift my approach here. I found an XT single piston caliper in my tool box which could get me through the next couple weeks here.
 

Da Peach

Outwitted by a rodent
Jul 2, 2002
13,681
4,904
North Van
its worth a shot, depending on how exactly @manhattanprjkt83 broke them :D
If the new XTR are anything like the older ones, they require regular bleeding to feel like they're supposed to. To the point where it falls out of the category on "maintenance" and into the "part of general use" category. That's a lot of fucking around with pistons that shouldn't need to happen.

Absolutely just riding along...I'll give it a shot, see what happens.
Exactly. Especially if you have a backup brake to keep you rolling. For the amount of shit floating around on the internet about Shimano brakes (to which I have contributed much) Shimano ought to give a loyal customer the benefit of the doubt.
 

manhattanprjkt83

Rusty Trombone
Jul 10, 2003
9,644
1,214
Nilbog
XT Brake held up fine, Shimano warrantied my XTR piston, new caliper on the way.

Snowshoe was sublime this weekend, everything was riding great, there is some newish stuff hidden in there from some of the enduro series which rips!