How to get both pistons out of the back brake?

[pnedac]

Hi guys,

Rebuilding a 1980 GSX750 and I have completed the full caliper rebuild of the front brakes, but on the back there are two pistons and I have one side out but that makes it so that the other side cant get any pressure with the air compressor to push that piston out. I tried to put a piece of rubber between the two pieces to block the flow of air, but I get nothing. Any suggestions?

I have the rebuild kit for the back, but I can't really proceed until that darn piston is out of there.

Any and all help is greatly appreciated. Thanks!

Pnedac

[hampshirehog]

Put the piston back in and put some thin pieces of wood in between the two pistons, both pistons pushed all the way back. Pump the caliper a bit and remove one piece of wood. Now push on the side that came out easily so that the stuck one wants to move as you pump the caliper. Repeat, working both pistons out a bit at a time.

[john82q]

Or you could undo the bolts and split it in two halfs and apply the air direct to the passage.

Theres a small seal in there you will need a new one.

http://www.cmsnl.com/suzuki-gsx750-1980-et_model13703/sealpiston_6910745000/

[1_v8_merc]

Split mine in half, pressed it down so that the little seal part was pressed on a flat rubber slab, then hit it with air compressor. It took multiple attempts and had to load the compressor up really high, until the piston finally gave way.

The piston will probably start to move, once you load it with air. But sometimes it stops suddenly, this is where you need to keep holding the air pressure in there, wait a few seconds, and it should start to move again. If it doesn't move again, you need More air pressure in the tank, or a better compressor, lol.
(you might also be leaking out of the caliper, so double check, I had to press down hard to fight the air trying to escape threw the tiny seal. You gotta get rough with her, lol)

[duaneage]

Wear safety goggles for all this, don't be careless.

[chuck hahn]

If the one piston doesnt come out, once you take out the 2 big bolts that hold the halves together, you cna again apply air to the back half where the rubber oring seals the oil passage between the 2 halves. Close the bleeder and stick the air hose against the hole...done.

[chuck hahn]

hadnt read the entire posts...I see the split and air has well been covered...carry on.

[pnedac]

Defeat

All the effort was for not. I lost the epic battle. I had full contact and full air pump going into that bad boy and it did not budge one stinking mm. It is not overly surprising with the amount of grime and rust that is on the outside and based on what I've seen on the other calipers, but it sucks not being able to claim victory. On a good note I was able to order a good used one on eBay for pretty cheap with new pads.

Thank you for all the input. I learn a lot each and every time from you guys and I appreciate it.

Happy Turkey day!

Pnedac