XTR Calliper Problem

[Alien Racer]

Need some advice with Reaccuring problem.

Had bike in for brake bleed and checkup, rear brake was rubbing rotor.

They bleed the system and it was fine till after first race.

Now one calliper pusher is not retracting to orriginal position!

Same problem as before!

bump! Please help fed up with brakes!

 

[Overlord]

Had the same problem with mine. Took the pads out and removed the caliper from the mounting bolts. Cleaned it with a rag and sprayed a little bit of silicone spray onto the piston. Insert finger and pump the brake a few times lightly. Wipe excess silicone spray off and reassemble.No more problems with a sticky piston. 

[Titanium Rocket]

This is a common problem, particulary with XTR calipers; some sites call it a "lazy piston". Caused by dust particles getting in between the piston wall and the seal. Onetime has it right, but I don't find it necessary to remove the caliper from the mounting.

 

I just remove the pads, and squeeze/pump the brake lever SLOWLY so the pistons come out. Don't squeeze too much or they'll pop out and leak all the brake fluid. You will notice they do not emerge evenly. Push the faster one back with a soft tool (a plastic tyre lever is ideal), squeeze some more until they are evenly out by just 2 - 3 mm. 

 

Now blast all the gunk off the pistons with Clean Streak, thread a rag through the caliper and clean/buff throroughly. Finally, put a few drops of oil on the walls of the piston, just to lube the contacts with the seals. Force the pistons all the way back in with your tyre level, replace pads, job complete in 6 minutes.   

 

Not sure how much dirt riding you do, but I perform this process about once a month to prevent recurrence.

[Alien Racer]

 Itried the Silicone spray after i cleaned it with Disc brake cleaning spray, no luck!

 Any other idees?

[louis0852]

buy magura's, solves alot

[dirtrider]

LX would solve even more !

[GoLefty!!]

raleighman, the problem with your XTR calipers seems terminal.

 

which model XTR calipers do you have? If its the XTR M965 then this is a known issue and the calipers should be fixed under warranty by Coolheat.

 

The problem is with the rollbacl seals in the caliper which does not have enough stiffness. There is a replacement seal for the caliper that fixes this but the tools to open the caliper are not available for sale, only Coolheat can replace it for you.

 

\Good Luck

 

PS:

Onetimes temp fix is the correct method but if the problem is still ongoing then replacement of the rollback seal is the only solution.