[decolvin]

Hey, all. Time to pick yer brains for some ideas. Trying to disassemble the calipers to rebuild them. I managed to get one piston out by hitting it with air pressure. I then clamped a small wood block with a rubber gasket over the empty bore to attempt to get the second out, but the seal is not holding the air (obviously didn;t hold fluid either). It won't budge. Any ideas how to get it out without screwing it up? There's not enough sticking out for a grip with soft-jawed pliers.

 

[Blindstitch]

Can you get the old piston back in?



If so put it in and then put two paint stir stick inside the caliper so when you hit it with air or other. Then when the one piston is at its max then all the pressure is on the other to come out. Others have also suggested that a bit of presser in may help the piston come out.

 

[decolvin]

There was i bit more of the decond piston sticking out when I started, but when it wouldn't come out easily, I thought if I could get it moving in the bore it might loosen it up enough to remove it. So I pressed the piston further into the bore hoping that it would then move out easier. That didn't happen.

 

[decolvin]

Thinking of inserting a thin #11 exacto blade alongside the piston and cuting the seal.

 

[Blindstitch]

Well if it went in some then it should come out. Seems like hydraulic pressure might be stronger than air. Or at least it's more hands free. Worth a shot to push that piston in some and bleed the brakes and pump the hell out of it with something blocking both pistons from coming out completely.





Other than that all I can think of is some sort of tool that could expand to fill the hole in the piston with the ability to turn it. Kind of like those pipe expander.

 

[bandit]

Hey, all. Time to pick yer brains for some ideas. Trying to disassemble the calipers to rebuild them. I managed to get one piston out by hitting it with air pressure. I then clamped a small wood block with a rubber gasket over the empty bore to attempt to get the second out, but the seal is not holding the air (obviously didn;t hold fluid either). It won't budge. Any ideas how to get it out without screwing it up? There's not enough sticking out for a grip with soft-jawed pliers.

iv had similar problems last week.

lubricate that 1st piston and put it back in.hook them back up to the MC.bleed and pump them out.you will find the pressure will cause the easy one to come out first.put a g-cramp over it.ie,dont let it push out.as the tight one starts moveing release the g-cramp gradually...so,they both come out at the same rate.

i think you will wreck something,going in any other direction

 

[Condo]

Although my ride is an '80 with the single piston I was faced with a similar situation. There was so much white corrosion inside the dust boot I probably should have not bothered, but I did anyway. First I pulled the incoming line and loaded the chamber with PB Blaster as well as PB'd the front side of the piston. Then I microwaved a damp towel until it was to hot to handle, wrapped the hot towel around the caliper, repeated this a dozen times over the course of the day, bleed the system and pumped out the piston. It's pitted and most likely shot, but it did come out.

 

[tmoll]

Dan, You may want to read through this old thread where I had the same problem.

http://cx500forum.com/index.php?/topic/4371-brake-repair/

Since my MC was not working and everything was disassembled, I elected to do what I would consider to be the last resort and used a grease gun attached to the bleeder to hydraulically pump the piston out. It works great and is a very controlled extraction, but there is a bit of a mess to clean up afterwards - getting all of the grease out of the caliper. If you can hook yours back up and use the normal brake fluid hydraulic action as others have suggested, it should work just as good with easier clean up required afterwards.

I have just ordered all the parts to totally rebuild mine. For a GL500i, all the parts, not including new hoses, is almost $250 including MC kit, so figure around $350 for a total rebuild of the front braking system on a 2 disk system with new SS lines. Probably more than the whole bike is worth in its present state.

Good luck! You will get them loose with a little effort and ingenuity.

 

[frenzy_rumble]

I had a similar problem. ran it through the ultrasonic cleaner a while, added generous amounts of liquid wrench and WD-40, applied a little air pressure to the inside and it popped (literally) out.

 

[cpt137]

If nothing else works you can by a zerk the bleeder thread size at NAPA and use a grease gun to pump it out. I've managed to get all others out but one and I had to do that. And I've done a lot!