Thought I'd share this tip with you guys.
I was cleaning up a pair of old brake calipers I picked up on ebay a while ago. They looked to be in very good condition but I couldn't get the pistons out!
Thought about hooking them up with an old master cylinder etc and pumping them out with fluid
(probably the best\safest way) but I was too lazy and not in a rush.
I don't have a compressor so could blow the piston out - and avoided firing a piston into the ceiling (who has done that?
)Tried levering them out gently - and one did indeed come out! Sweet. No pits, hardly any rust. Good to go.
The other of course was stuck. So I tried bathing in boiling water then cold - to shock it. Nope.
Tried putting it in the freezer to shock it some more and let the difference in thermal properties of the steel and allow body sort it out for me. Nope - still stuck.
So.. I filled it up with water, sealed the holes and put it back into the freezer.... 30 minutes later the water froze and pushed the piston out.
Added by another member,"It1"
"On a twin piston caliper, you would leave the other piston in held by a C-clamp. to allow one piston to come out"
