Removing front caliper pistons... tricks?

[914zim]

Hey guys:
I'm trying to get the pistons out of the front calipers.
It looks like they're seized, but they're not too bad looking.
I cannot move them by hand. I've sprayed tham with Liquid Wrench to try and loosen them up.
I've used the trick to blast compressed air to remove one of them in the past, but I was wondering if you guys had any other ideas.
I was thinking of just grabbing the very tops with a pliers and trying to twist and pull them out, but that didn't seem like the best idea. I do have the rebuild kits on order.
Any ideas are appreciated.
Andy...

[mike_the_man]

I just did this a couple of days ago. Here is what I did:
I put the caliper back on, bled it a bit, then removed the pads. I then used a pair of flat vice grips to clamp one piston on one side, then I just stomped on the pedal till the piston popped out.

Be careful that the piston doesn't fall on the floor and get damaged, and it makes a real mess because all the fluid leaks out, so be prepared. It's kind of a PITA to have to bleed the brakes each time to get each piston out, so another trick that I used was to plug the lines coming out of the master cylinder for the rear brakes and the side opposite to the one you are working on. That way you only have to bleed one caliper. All I did to plug the MC was buy a couple short pieces of brake line from my FLAPS, then kink the line in a few places to seal it.

Another nice thing about doing it this way is that when you are done the caliper, you can put it back on and bleed it and make sure that you can get a firm pedal, and you know for sure that that particular caliper is working good. It's a good way to test the front calipers individually and makes trouble shooting a little easier.

Hope this helps,

[sammyg2]

Easiest way I know of is to use a grease gun.
Put an appropriate sized zerk fitting on the caliper and just grease it up. Most grease guns can build up over 2400 psi and since grease is non-compressible it will not expand like compressed air will.

WARNING: There may be trapped air in the caliper, you must bleed it before pressuring it up to prevent it from going off like a cannon. Appropriate PPE (personal protective equipment) should be worn i.e. eye, hand, face protection etc.
Some sort of clamp or vise should be used to contain stored energy yada yada.

Can ya tell I've been writing too many procedures lately?

[Dave at Pelican Parts]

Not a bad idea to stick the caliper in a bucket, too. If it does "go off like a cannon", the mess will be unbelievable!

--DD

[914GT]

Here's another way, I did this on BMW calipers from the junkyard - remove the pads and the piston dust seals and retainer rings. Take two medium size regular screwdrivers and come in from opposite sides and carefully pry from the grooves using the caliper housing for leverage. If you apply even pressure on both sides it will come right out.

[Andyrew]

Compressor air, with rubber grommet so the air device has good seal, then use a block of wood to keep the pistons from hitting each other (or yourself) small thin block of wood works good. make sure you have no body parts or anything in the way of the pistons (asside from the wood). I had very stuck pistons that I did this with. then some pistons that I needed, but not the calipers, couldnt get the pistons out with 130psi, so I sawed the calipers and the pistons where stuck, but good condition.

Hope this helps!

[914zim]

OK guys, thanks a lot for the tips, they're good ones!
Andy...