xr250 rear brake sticking

[eddclarke]

Hey

What can cause a rear brake to start sticking? It got to the point where the disc was glowing red!!!

I have only just fitted a new master cylinder, could this be the cause?

Cheers
Ed
____________________
Honda XR125L 06 ----> Yamaha FZ6 05 + ex SAS XR250 --> VFR800 + XR250r

[Blue_SV650S]

Sticky piston, sticky slider pins ... a stone jammed in ... a partridge in a pear tree?
____________________
The purpose of life is to fight maturity.

[robocog]

Assuming they work on the same principal to car master cyls it could be a case of over adjustment on the M/Cyl

They do need a bit of "free play" or slop when the brake pedal/lever is fully released, otherwise the fluid cannot return back fully

What happens in use when someone has over enthusiastically adjusted the "slop"... the pads heat up, which heats the fluid a bit, it expands and instead of making it back to the reservoir it can only put the brake on harder, which heats the fluid even more, causing it to lock eventually (and sometimes quite spectaculalry)

easy to test by trying to retract the pads and pistons by hand...cannot be done?

slacken the master cylinder pushrod right off or disconnect the pedal from it completely (whichever is easiest) and try again

If it still fails time for a stripdown of the calliper

(either way make sure you have something ready to keep the overflow of fluid from spilling out of the reservoir - its nasty stuff and makes a mess of paint/some rubbers/some plastics)

Regards
Rob
____________________
Needs a bigger garage...