Brake caplier piston stuck

[tamo3]

I'm rebuilding '91 Toyota 4x4 brake caliper.

I could've remove 3 pistons, but last one cannot removed.

I could've pushed in a little bit using clamp. Pouring PB Blaster, apply heat gun for long time before push air from my 60Gal air compressor.

The piston won't move at all.

Does anyone have tips to remove piston?

Thanks,

tamo3

Edited April 10, 2013 by tamo3

[doradox]

Put it back on the car and push it out with hydraulic pressure.

Steve

[cbuczesk]

Put it back on the car and push it out with hydraulic pressure.

Steve

That should do it. I think I used a grease gun years ago. Threaded it on and pumped...

Chuck

[Willoughby Z]

Do NOT use compressed air! The pressure that builds up can be devastating. If you are lucky enough that the piston releases before some other component explodes, the piston will be a projectile like you have never imagined.

[EuroDat]

I agree 100% with Willoughby. Safety first. The piston can turn into a projectile like you wouldnt beleive is possible.

I would put the caliper back together, fill it with fluid and fit a tube with grease nipple and push it out with a grease gun. Use a block of wood between the two good pistons and a clamp on the other good piston opposite the seized piston.

If the clamp wont hold, you can use a piece of pipe (same length as piston) which will fit over the piston and a thick metal plate to stop the other piston entering the pipe. The free piston will push it over the seized piston and stop. That will give you enough room to push the poston into the pipe.

There is a mix of ATM fluid & Acetone that does wonders for freeing up stuff. Give that a chance to soak in.

Goodluck

Chas

[tamo3]

Thanks for your advice.

If i use grease gun, do i need to push in grease into brake caliper?

[cbuczesk]

Thanks for your advice.

If i use grease gun, do i need to push in grease into brake caliper?

Yep. You'll have to clean out the grease after the piston pops out. Keep your fingers out of the way just in case!

Chuck

[tamo3]

Thank Chuck.

I put it back on the car and pump the brake pedal.

It seems something wrong with my booster or BMC or PB.... Brake fluid does not come out well.

Since Brake booster and BMC are rebuild. I forgot to check the length of the the push rod of brake booster.

Also, BMC is from '79 280zx 15/16 BMC. I got rebuild kit @ BrackDragon for '84 BMC. I just used piston of the repair kit. since it looks same. But once I push it in,it was so tight.

Too many variable need to narrow down the issue....

I will try the grease gun solution.

Thanks!

[EuroDat]

I tried one of those piston kits on my 7/8" MC and had similar problems. The piston cups were a little different so I couldnt use them on the original piston in my original MC. Ended up buying a new Beck/arnley from RockAuto. Being brakes I just didnt trust it anymore.

For the caliper I have used an old brake line and I brassed an old uni-joint grease nipple in the other end of the brake line. I filled the caliper up with engine oil. I was replacing all the rubber components anyway. You need to get all the air out, otherwise you will be compressing air and using a lot of grease.

After you get if out you can clean the oil and grease out.

Chas

[tamo3]

Thanks Chas.

Over the weekend, I rebuild BMC and swap piston springs from original one. The stiffness did not changed. I guess it same situation of your 7/8" BMC.

Since I rebuild, I give a shot to put it back whether it works or not.

pumping brake pedal more than 300 times, the piston from caliper did not comes out nor other piston moves.

I guess I need to rebuild caliper again...