Rebuilt caliper piston stuck?

[sneakyRedPanda]

I ordered new remanufactured calipers. Lucas Girling front calipers. I painted them and let them sit. The brake line hole was plugged with a rubber plug and the bleeder valve was shut.

One side is compressed already but the other side, I cannot for the life of me get this piston to compress. As far as I can tell, the piston is in straight and doesn't appear inserted improperly - but I seriously can't get the last 6-7mm of the piston back down. Tried a C clamp and a block of wood which broke the wood, tried a C clamp and an old brake pad which did nothing.

Is it possible that it's actually rusted after sitting on a shelf after it was painted for a couple weeks? Like I said, the brake line hole was plugged and the bleeder valve was closed. On top of that, I figure even if it rusted a bit I would be able to get it to budge. I've filled it with PB blaster and I'm letting it soak overnight.

Any suggestions? I have my entire engine out and the MC/booster removed so I can't just hook it up and give it some pressure. I don't have an air compressor either.

[jlevie]

I don't see rust as being the problem, considering the force you have applied. Since you don't have any way to get the piston out, I'd suggest taking it to a shop and having them extract the piston and determine why it won't retract.

[sneakyRedPanda]

I don't see rust as being the problem, considering the force you have applied. Since you don't have any way to get the piston out, I'd suggest taking it to a shop and having them extract the piston and determine why it won't retract.

Yeah this is the route I'm going to go - too bad it's a long weekend. I'll bring it in Tuesday and hopefully I'll remember to update the post. Stay tuned.

[sneakyRedPanda]

Took it to the shop I frequent and they removed the piston. Get this - the piston was too long! It was bottoming out on the bore. Whoever rebuilt it used the wrong part. I ordered a replacement and the new one works fine.

[estoguy]

Some rebuilders aren't that great. I had my rear calipers replaced, and I had one of the seize up TWICE. I went with a remanufacturer here in Ontario, John Stuart Power Brake, and those calipers have worked amazing.