How to get pistons out of rear caliper?

[duaneage]

If you remove and drain it life will be easier on you. Simply plug the joining hole shut with a plug and finger and then pressurize with a blow nossle with rubber tip like described above. It WILL pop out of there. Follow the precautions mentioned, be careful.

Don't do this.

If you place a finger near a hole and pressurize the fluid behind it the fluid can be injected into your skin. If you have to work with air under these circumstances use no more than 30 psi. One small slip could be very bad.

vaccine injection devices use air pressure to administer with, brake fluid can be harmful if injested.

[DaveDanger]

I personally would be very hesitant to touch the pistons with anything made of metal. Screwdriver tips, pliers, channel-locks, anything. Unless I miss my guess, those pistons are made of aluminum. The instant that you apply pressure of any sort to that polished, machined surface, you're going to mar it. Scratch it. Scar it. Damage it. Then you have a piston that no longer fits smoothly into the cylinder bore... draggy, sticking brakes if they function at all. Partially push the first piston back in place, enough to seal the o-ring a bit and hold that one in place while you re-pressurize the caliper with air, hydraulic fluid... whatever. That will force the pressure back onto the sticky piston. Basically what you want to happen is to first remove the farthest piston from where the fluid or air pressure comes in to the caliper. Once you've gotten that farthest one, the closer one will still usually pop out with moderate pressure. Even with the pressure leaking through the orifice, the first piston should pop out.

[rikusa]

Just strip and clean one side at a time.

[DaveDanger]

An elegant solution. That just HALTS me in my tracks. Ya'll just BRAKE me up. BIND me up and wrap me in a red bow. Somebody STOP me! (I have entirely too much fun here )

[retrex]

Piston removal

This may be too simple, but whenever I work on my seals I just pump the pistions out to their furthest travel using extra brake fluid. If I am lucky one usually becomes unseated and pops out. The other one I pull out with a reverse pair of pliers, pliers that push out rather than clamp onto. In my case, 81 GS1100EX, I have to split the rear caliper to get the second piston out. Good Luck

[Hoomgar]

If you remove and drain it life will be easier on you. Simply plug the joining hole shut with a plug and finger and then pressurize with a blow nossle with rubber tip like described above. It WILL pop out of there. Follow the precautions mentioned, be careful.

Don't do this.

If you place a finger near a hole and pressurize the fluid behind it the fluid can be injected into your skin. If you have to work with air under these circumstances use no more than 30 psi. One small slip could be very bad.

vaccine injection devices use air pressure to administer with, brake fluid can be harmful if injested.

That's why I said what I said Duane. I would say please reread but maybe I wasn't clear enough if even you didn't follow. I said to use a plug for that very reason. Thought it would have been sufficient rather than going into every possible scientific explanation as to why. Thanks though for the clarification If you missed that it is most likely possible that the original poster may have too 8O