GT6 disc brake piston removal GT6+

[19_again]

Can I use PBB on this component or will that pose a problem down the line as far as contaminant in the brake fluid? I would of course clean out the lines, but still need to ask. Otherwise is there any way to get the stuck piston out of the caliper housing. All fluid has been drained, and the bleed line is open so no vacuum but no movement. sat for 20 years.
Mike
PS since I see the pistons listed as an available part, I assume (gasp) that they must be able to be removed.

 

[Andrew Mace]

Yes, they are removable. Have you tried the two-pry-bar trick, one on each side of the piston lip? Assuming it's all off the car, you can't easily (albeit carefully) use the brake pedal gently to get them started.

I'm thinking you might be ok with judicious use of PBB for the sole purpose of loosening any rust on or around the piston...since you'll be replacing the seal regardless. I'd not want much to get deep into the caliper, though.

 

[19_again]

Yes, my concern as well. I'll try the pbb and I've got some Freeze-off that is new from CRC that I might try as it's not quite so "oily".
Thanks for the response, Andrew.

 

[DrEntropy]

Caliper off the car, benched. Preferably in a vice. A piece of 1/4" plywood as a surrogate brakepad, somehow clamp it to the non-stuck piston in the fully retracted position... keep yer fingers clear of the piston area, close the bleed screw and apply compressed air to the supply hole. It'll come out with a BANG.

 

[19_again]

At this point both pistons are stuck. So I'm presuming that a block of wood is also serving as "padding", how about if I use a block of wood that is about an inch or so less than the distance between the two pistons and positioned between them and then hit it with the air?

 

[DrEntropy]

One or the other will pop out first. Trick will be to clean and reseat the one coming out and get the OTHER one to pop.

 

[19_again]

Yeah, well I figger one will come out, and as you say I'll clean it up and reposition. Then with a vise I hold the newly cleaned unit in place and blow the other one out. Voila, sounds sooo easy, kinda like a u-joint replacement.

 

[Gliderman8]

The Doc is right... that's exactly how I got my pistons free of the calipers. The only thing I will add is that I wrapped the calipers in a rag to contain the pistons when they "pop" out. Careful... cause they can fly out and do some damage. Good luck.

 

[DrEntropy]

'tis a bit like grenade practice!