Caliper Rebuild - 3 pistons stuck

[speedyspaghetti]

Hey everyone,

I'm in in the process of doing a caliper rebuild, but I'm having a hard time with 3 of the brake pistons. I took out the dust boots, and then used the compressed air / wood method. One of the pistons shot right out, 1 budged a bit, an the other 2 did not move at all. Is there something I'm doing wrong, or do I have frozen pistons? I'm blowing the air through the hole where the caliper would connect to the brake line - is this correct? Or should I be blowing through the bleeder nipple? Any other suggestions? I have tried prying / pulling on them since I do not want to damage them.

Thanks!

[TrumpyAl]

"shot right out"

Does that mean that one of the pistons is all the way out and now you can't pressurise the space behind the others?

[Quadcammer]

just use 2 screwdrivers to pry them out. should be a non issue

[speedyspaghetti]

Originally Posted by TrumpyAl

"shot right out"

Does that mean that one of the pistons is all the way out and now you can't pressurise the space behind the others?

It pushed most of the way out and then I pulled it out by hand - should I have kept it in so that I can get full pressure on the others?

[TrumpyAl]

Yeah, pop it back in and use the block of wood to keep it from being pushed out again.

Try to use air pressure to move all of them partially out, and then lever them with screwdrivers to get them the rest of the way out.

[speedyspaghetti]

Originally Posted by Quadcammer

just use 2 screwdrivers to pry them out. should be a non issue

Marring that recessed ring, while I'll try to avoid it, won't damage the function, correct?

[speedyspaghetti]

Originally Posted by TrumpyAl

Yeah, pop it back in and use the block of wood to keep it from being pushed out again.

Try to use air pressure to move all of them partially out, and then lever them with screwdrivers to get them the rest of the way out.

Yeah that makes a lot of sense... I feel stupid now. Oh well. Thanks!

[Quadcammer]

Originally Posted by speedyspaghetti

Marring that recessed ring, while I'll try to avoid it, won't damage the function, correct?

they are actually tougher than you might think, but nah, a few scratches there won't affect anything as its just the dust boot retainer.

You can wrap the screwdriver with a paper towel if you're worried

[speedyspaghetti]

Originally Posted by Quadcammer

they are actually tougher than you might think, but nah, a few scratches there won't affect anything as its just the dust boot retainer.

You can wrap the screwdriver with a paper towel if you're worried

Gotcha - thanks! Hopefully this rebuild and new rotors / pads will solve my vibration once and for all.

[TrumpyAl]

Originally Posted by speedyspaghetti

Gotcha - thanks! Hopefully this rebuild and new rotors / pads will solve my vibration once and for all.

Do pay attention to the bed-in procedure.

And next time around, don't switch pad compounds without also replacing (or machining) the rotors.