System felt sticky so gave the pistons a lube. However, it seems to be the lever that’s the problem. No spring in the lever whatsoever. I’m guessing a sticky seal in the master cylinder.

Is this repairable or is it borked? Not keen on giving it the good news with wd40 or gt85. I imagine neither is great with the seals.

Please, no messages about brake A being crap, should have got brake B. These are not my brakes. If my brakes were doing this, the seal would have been replaced and I’d be on my way.

Cheers.

Mine did the same and I bought a new lever for £25 from crc. Don’t think there’s much else you can do to fix it I’m afraid.

Thanks, I was thinking that might be the case. There does seem to be a number of levers dying like this.

If my brakes were doing this, the seal would have been replaced and I’d be on my way.

I very much doubt that – they don’t make spare seals for XTs.

On a more constructive note, if you have a look at the underside of the brake, you’ll see a concave section on the lever that mates with a rounded part on the main body (not sure what you’d call something like that), close to number 8 on this diagram…

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/BL/EV-BL-M785-3158A_v1_m56577569830796605.pdf

Is that clear or caked with crud. Or, as I think I read on here sometime ago, that area can wear out or something.

Thanks, I’ll have a look at that. What I meant about the seal is that my brakes are not shimano so I’m more familiar with mine and I can get spares.

Known problem and they’ll warranty it no questions if within the warranty period and you have a receipt. Mine did it last summer, brake lever didn’t return locking on the brake… Fun crash that one.

If it’s the same as my 988 XTR the piston is a plastic of sorts. As grit gets in it gets scored and sticks in the bore. You can pull it apart and with fine wet and dry rub it down till it moves smoothly in the bore.

You need to be really careful if you try to remove the seals, but you can do it with them in place. Pulling the lever apart is all a bit of a fiddle, not to mention putting back togther!

What I meant about the seal is that my brakes are not shimano so I’m more familiar with mine and I can get spares.

Gotcha. My apologies for presuming…

Yep – common problem on latest XT brakes

In the last 2 years i’ve been through 2 rear levers and 1 front lever.

Seems to be grit getting into the cylinder/piston interface

Happened the other week when i was halfway around Afan – very annoying. So i twatted it with a rock for 5 minutes and it sprung back 🙂

Happened again a week later but wouldn’t swing back

Very annoying – but as the lever is only £30, then its a quick fix – just annoying when it happens on the trail

I’ve also got SLX brakes, but i’ve not experienced it on them – but they are only 18 months old

Ha, another mate with another one like this.

I’ve had 2 go, I was using a spray grease on them every now and again, maybe it fubard the seals.

Both claim to have used nothing. Doesn’t look like they use soap and water either.

I’ve had 2 xtr trail brakes do this over about 4 months of use, slx on the other bike have been faultless, replaced my xtr’s with xt’s in the hope that it was just the xtr’s, damn.

There is a brass type roller in XT levers that can gunk up quite easily. It stops turning and then it stops the lever moving nicely. I haven’t got a picture at the moment, I’ll try to find one. Cleaning that up can help quite a bit.

stevede

If you’ve still got your old levers I’d be interested in them?

Mike

Most new XTs should still be in the 2 years warranty shouldn’t they? The spares “availability” is a pain in the arse but the warranty support’s good

my mates had 2 sets of xtrs do this, we managed to bodge a fix in the alps in the way michaelbowden described ^^^

Did wonder if the servowave mechanism might be guilty. Is that accessible once you remove the lever then?

Yep, but refitting the levers can be a proper PITA. Getting the little spring to stay in place is always an art.

Is that spring just responsible for returning the lever or does it “pull” the mater cylinder piston back? Or is there a spring inside the bore that pushes the master cylinder piston back?

There is a spring behind the piston, but as the piston gets scratched up by grit the spring is no longer strong enough to overcome the friction between piston and bore.

You need to remove the piston and rub it down with fine wet and dry untill it moves freely.

Presumably this is covered under warranty.

XT have 2 year warranty
XTR have a 3 year warranty