[Bikeeveryday]

I just got some shimano M755 brakes at a bike swap and unfortunately, they are leaking at the piston/ seal. Have any of you guys successfully rebuilt the shimano brakes using aftermarket seals from an o ring store? There are stores online called oring usa etc.... and I was wondering if any of you guys had the metric or standard measurement of the replacement o rings. That, and what material should I get so the mineral oil doesn't react with the o ring and swell it?

 

[Wombat]

They don't use o-rings or normal seals. The piston sits in a "rubber' cup that has holes in it to allow the oil in. I'm sure it's a standard part for something, but you'll need to pull the calipers apart and take the cups (from memory they have different sizes for the big and small pistons) to a seal shop to see what they can match them to.

Good luck, and luck us know what you find.

Tim

 

[Bikeeveryday]

oh okay

Yeah, I haven't pulled them apart yet. But I hope I can find some place around here that actually has brake seals that small. I'm really hoping to revive these old brakes because I know they have a lot of potential!

 

[qkenuf4u]

Yeah, I haven't pulled them apart yet. But I hope I can find some place around here that actually has brake seals that small. I'm really hoping to revive these old brakes because I know they have a lot of potential!

LOVE MINE !!! def let us know if you find what you need.... ive kinda been thinking about the rebuild part myself lately.... mine still work perfect but ya never know.... :skep:

 

[janvierdoire]

Bikeeveryday,

Any luck reviving those 755? I'm working on a pair myself and running into some problems. I can't get the lever to not go all the way to the bar even after multiple bottom-up bleeds. I clean the pistons too because they weren't coming out equally. I suspect some leaks at the pistons. I noticed the reservoir leaking too, but that should cause the lever to go all the way in right? Any ideas?