My Front Brake Is Stuck On, what do I do?

My front brake is stuck on and I cant move the bike.
OK, this happens a lot, the longer the bike has been left unattended in storage, the more the chance that the brake fluid has gone all goopy and gelled up.
Now to free the thing temporarily, you whack the caliper body with a Rubber mallet, this will shock the piston back a bit.
Bleed the brake until fluid comes out of the bleed nipple, you know, on, off, on, off etc.
Once clear is coming out, try the brake, if it still stick, then I usually take the back of the caliper off and then with the nipple locked tight, I simply press the brake lever until the pad and piston pops out.
Keep checking fluid levels in the master cylinder though.
There is 2 ton of pressure there and this will push the piston out, make sure you have some rags over it as it can POP under pressure and get brake fluid all over the joint, and paint does not like brake fluid at all.
I then take the caliper off, remove the piston and “O” ring and I then clean it all out with lacquer thinner.
I use a Dremel Rubber wheel and hone the bore of the caliper out to get any tiny corrosion marks out and then I clean the recess out for the “O”ring.
If the piston is pitted I usually make new ones on the lathe from stainless, that way it will never rust or corrode in the body again, its the rust pitts that catch the wall or the seal and stop it from sliding back into the caliper body.
Then – I simply fit a new ring and clean the piston up and put her all back together, re-bled and there you go, a functioning brake once again. Taa Daaaar! –
We sell a Brand New Piston though that is machined out of Stainless steel and this will fix the issue that you are having from your old piston.
Grab a spare, just in case your old one does take a bit of a crap and the pads are sticking.



Steve Carpenter

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