Dumb Q: How Extract Piston From Caliper
 

Here's my clueless question of the day. How do I extract the pistons from a monoblock brake caliper? I'm rebuilding the caliper and need to re-use the pistons. I don't have an air compressor. Is there some other readily available way or clever trick to pull or push the pistons out? Or will I need to drop by my mechanic and ask for a favor?

Use a bicycle tire pump and a short length of metal brake line.

No air compressor? Just go get one. They are cheap these days (in more ways than one). I find them at garage sales all the time. Fairly good for $100. Better for 150. Even those Harbor Fright ones for under 100 will do, but I'd rather have a bigger one used than a tiny one new.

Tomorrow is garage sale day.

I use an air compressor as well.
If you do the same, make sure your fingers are nowhere near the pistons when you pull the trigger on the air gun. You could loose a finger easily.

-Brad

a search for "caliper rebuild" will help.

I used the compressor that is used to fill up the space tire. It does not take any herculean compressor to pop out those pistons. Any old little thing will do it.

Just make sure all the brake fluid is out of the caliper, cause when you can't get the piston out, and you cut the compressor off all that brake fluid blows back out at you. Trust me, a face full of brake fluid is not fun!

Britt

same here. The little plastic tapered cone that comes with the thing has a small enough end to push air into end of the short hard line.

Yeah I used the small plastic nozzle on the end that came with the compressor I bought at costco for under $20.

Since this turned into a pistion removal technique revisit, I bury the whole mess in an old towel while keeping the air nozzel in the hole. The I pull the trigger, less noise, no mess and my fingers are holding the towel, so I know where they are.

There is a cheaper, and safer way than air for really bad calipers. Replace the bleeder screw with a grease fitting. Then buy a good grease gun (~$20), and pump it full of grease. The piston will come out nice and slow; and there won't be the risk of losing a finger or messing up your piston. If you want it to be a little cleaner, use the grease gun and fill it with cold gear oil (~$2). The gear oil cleans out alot easier if you don't have access to a solvent tank.

Take a few fasteners you have laying around to see what size your bleeder screw thread is. This will save you additional trips to the hardware/auto parts store.

Install the caliper back on the car with the pads off. Jump in the car and pump your brakes. The pistons will contact the disk. Take the caliper back off. Get a little hose clamp and clamp it around the piston. Now you have a place to put your channel lock pliers onto and not damage the surface of the piston, and start to wiggle away. Do one side at a time and you will not have any trouble
Jesse

Thanks, guys. I knew there must be a way to do this without buying any new tools to clutter up the garage. I have the electric tire pump that came with the car, and my local hardware store should yield up the right threaded bits. (I can't use the pump the brakes trick because the calipers aren't the ones on the car.)

I knew the grease thing was gonna come up. If you do that, then you must super clean the caliper body and all passages. Then, you must rid the caliper of the solvent with alcohol. I'll stick to air.

When I used air (compressor), I put a small piece of wood in there to keep the piston from flying across the garage. Next time, I'll use a towel like Zeke suggested. You'll be amazed at how much force those things come out with!

Connect it back up to the brake line of the car and just push the brake pedal.