Brake caliper cleaning

[philc]

I have a set of brake calipers that are basically clean but the pistons are resisting my efforts to remove them.
They have moved since I started working on them and the seals getting shredded as they move.
They dont appear to be rusty, so Im thinking that rotting seals inside have jammed them up, I was thinking about putting them in boiling water for awhile, can anything else be damaged by doing this?
I dont have a compressor or else I would just apply air pressure.
Thanks

 

[Denver]

Hook to a master cylinder with old pads to stop pistons from popping out & pump out till nothing but clean piston shows. Soak in ATF 24 hrs use a piece of rag like a shoe shine rag to clean pistons, or a strip of a scotch scrub pad, if its to much for rag to clean. Get clean & press back in, its amazing how often seals are saved with this method.

 

[slabghost]

Many have used a grease gun on an open bleeder valve to successfully remove the caliper pistons. For safety you can stuff rags in the caliper to catch the pistons and wrap the caliper with another rag. I'm not sure boiling will help you much to remove the pistons.

 

[philc]

I let the first set boil for about 12 minutes, pulled em out and when they were cool enough to handle I pulled the pistons out without too much struggle. Now the second set is boiling..
The seals were toast anyway, the pistons dont look too bad though, very little corrosion.

 

[philc]

Ok so this set is jammed a bit tighter, I think I will try to find my grease gun..round here somewhere....
Will soaking in ATF harm/corrode the factory paint on the caliper? These are far cleaner than my old set and I dont want to mess that up.

 

[slabghost]

As far as I know ATF will not harm the finish but I can't say for certain. I can say for certain brake fluid soak will remove the finish.

 

[philc]

Ok, thanks for the info, gonna think this over a bit.

 

[Joep]

The boiling won't hurt anything other then the seals.. caliper is 4 or 5 pieces... piston(s), seal(s), caliper, bleeder... you most likely will want to replace the seals and bleeders anyway just for insurance and piece of mind...if you have one stuck.. you may want to inspect it thoroughly... for gouging.. scaring of both piston and caliper....you could remove paint and use caliper paint to refinish them..