E-Type brake caliper rebuild question

[billca]

I'm rebuilding the brakes on a '67 E-Type and have a question. I have removed the front piston/cylinder assembly from the caliper body and used air pressure to push the pistons out of the cylinders. Unfortunately, the pistons will only come out just barely far enough for the rubber seals to be exposed and air pressure to be lost in the cylinder. I cannot remove the piston from the cylinder by pulling it by hand. It acts as if the self-adjusting mechanism is perhaps stuck just when the piston is about to come out all the way out.

Does anyone have a suggestion for completing the piston removal?

Another clue is that the pistons were not retracting and there was excessive brake drag. That's why I'm rebuilding the calipers.

Bill C.

 

[Larry Kronemeyer]

Just keep soaking and trying. Push in, blow out.
Check the edges of the pistons that you can see for scaring or rust. Good Luck.
Larry

 

[Larry Kronemeyer]

P.S. Don't split the casings.

 

[billca]

Larry,
Thanks for the advice. I'll keep plugging away on getting the pistons out of the cylinders.

When you say 'don't split the casing,' are you talking about not removing the cylinder/piston assembly from the caliper? (I've already done this for the right front.) What's the consequence of taking this apart and how can I reduce the potential problems?

Bill C.

 

[Larry Kronemeyer]

Some of the older calipers came apart to help in cleaning, they were a bear to reseal with all the o-rings. Piston assemblies as you have you'll do fine, they are just hard at times do to the build up of dirt and dust and hardened seals. Using brake fluid as a lube helps control the swelling of the old seal.
Larry