Rear brake locked up...

[biskit134]

My rear brake is locked up tight. The piston won't budge, and the caliper shaft moves freely. The reservoir is full... any ideas?

[nd4speed]

Damaged seals, piston or cylinder walls?

Use compressed air and blow air backwards thru the hydraulic line to pop the piston out. DO NOT point the piston at your face while attempting this.

[biskit134]

It is out, it just won't retract. I was noticing that when I used the brake, it was locking down and I would have to manually return the pedal up to disengage the caliper. So, I took it off to try and grease the caliper shaft, but it moves freely. I noticed a whoosing sound when I would pull the brake pedal up after taking the caliper off, then, the piston went out, and now it won't retract...

[CR480R]

the caliper on my T3 did the same thing... I suspect its just worn out... A new set of pads seemed to fix it for now

[biskit134]

Ok, diagnose this for me. I pulled the caliper off, took it apart. The parts were NASTY, rusty even. I cleaned everything. I polished the piston. I put everything back together, and the piston moves with pressure, and seems to seal up good. I put it all back together and tightened everything down. Opened the zirk and went to pressing the pedal trying to pump the air out. I noticed the caliper was loose, even though everything was tight. I figured that would take care of itself when I pumped the brakes up. Nothing.

The brake will not pump up, and the pedal still does not return. I put my finger over the zirk, and could feel air pushing against it, and felt the vacuum when I returned the pedal to up. I pumped the break for like an hour no smurf, and nothing.

I pulled the reservoir cover and there was plenty of fluid. I bumped the front brake with the cover off, and like it is supposed to, fluid shot up. I hit the rear pedal with the cover off, and nothing. Not so much as an air bubble. Now I am thinking rear master cylinder...

Aside from that, is there anything I can check? Also, is the caliper pin supposed to be able to be turned? Mine wont budge. I rounded out the freakin edges trying to turn it. I took my dremel and cut grooves in the head of it and tried to turn it with a screw driver, still won't budge...

FWIW, the front brakes work great. It will do an endo...lol.

[rockhoundor]

take a piece of vacuum hose about 16" long, drill a hole in the lid of a 20oz pepsi bottle, fill 1/3-1/2 full of brake fluid, open the bleeder zerk fitting and press the end of your vacuum hose over the zerk, put the other end of the hose thru the hole in the pepsi lid and into the brake fluid, then pump away, you have just made a closed system one man bleeder.

[fulltiltrider]

Originally Posted by rockhoundor

take a piece of vacuum hose about 16" long, drill a hole in the lid of a 20oz pepsi bottle, fill 1/3-1/2 full of brake fluid, open the bleeder zerk fitting and press the end of your vacuum hose over the zerk, put the other end of the hose thru the hole in the pepsi lid and into the brake fluid, then pump away, you have just made a closed system one man bleeder.

Yeah what he said, and to add a helpfull hint. Push the piston back in as far as it will go and leave the clamp on it. Then bleed the brakes, that way you are not trying to bleed the open space in the caliper as well. Ive seen people try to bleed brakes for hrs and not get it. Clamp it down and pressure builds right up. If none of that works, I would say its your master cylinder, not the caliper