My old style (M965) Shimano XTR brakes have developed slightly lazy pistons on one side (the outer piston in both cases) after a period of several years… I know some people have had this problem sooner than others, but it seems its finally affected me.

Anyway… What's the best way to cure it (binning them and buying new brakes won't be happening, I happen to quite like them and don't mind sorting it out myself)? They've not totally stopped moving, but the inner piston is doing the bulk of the work, which leaves the outer pad invariably dragging slightly on the rotor which seems to be wearing the outer pad about twice as fast as the inner one.

Any help appreciated…

silicone – available in little bottles from Hope

works a treat – 5 min job

cheers Dylan08

Be more specific though, do what with it? Do I pop the pistons out and cover them in it?

Also, does silicone spray work as well as I have a can of that somewhere already?

squeeze the brake on and then apply a little oil to the piston (don't get it on the pads 8O), then push the piston back in.

StuF

Any particular oil? I have:

Chain Oil
Fork Oil (in 5wt/10wt/15wt/20wt)
Brake Mineral Oil
Engine Oil
Gearbox Oil
3in1 Oil

What's best basically?

I always use Halford's ATF fluid which is basically the same as shimano brake fluid but costs much less. You may have to repeat the procedure 3-4 times before the piston frees off entirely