Topic: Front brake Caliper - 80’ CB650C

[MTNman]

Hey guys;

I was rebuilding the front brake Caliper on my subject bike, and I ran into an issue.

The piston is just stuck solid in the housing…. Anyone have any good tricks to remove it? Or is it a “replace” issue.

Any help is appreciated, thanks in advance.

[bryanj]

Remove the caliper but leave the bleed nipple in and done up.
On your gease gun(of course you have one!) Unscrew the zerk fitiing from the flexible or steel pipe, GENTLY start to screw the caliper hose fitting remale hole onto the grease gun pipe NOTE CAREFULLY the threads are different and so will only go approx 2 turns DO NOT FORCE IT or you will wreck the caliper.
Pump the grease gun that you filled before you started and the piston will come out
Next spend many happy hours degreasing the caliper, remove the seal and de #$%*e the seal groove

[MTNman]

Remove the caliper but leave the bleed nipple in and done up.
On your gease gun(of course you have one!) Unscrew the zerk fitiing from the flexible or steel pipe, GENTLY start to screw the caliper hose fitting remale hole onto the grease gun pipe NOTE CAREFULLY the threads are different and so will only go approx 2 turns DO NOT FORCE IT or you will wreck the caliper.
Pump the grease gun that you filled before you started and the piston will come out
Next spend many happy hours degreasing the caliper, remove the seal and de #$%*e the seal groove

Could this be potentially done by hooking it back up to the brake handle and pump brake fluid through until it comes out? To prevent possible damage?

[Mark K]

I had a similar issue, but was not able to put it back on the bike to try to use brake fluid pressure to try to get it out.

Here's a link to an area on the forum that might be helpful. http://forums.sohc4.net/index.php/board,136.0.html

Good luck to you.

[MTNman]

I had a similar issue, but was not able to put it back on the bike to try to use brake fluid pressure to try to get it out.

Here's a link to an area on the forum that might be helpful. http://forums.sohc4.net/index.php/board,136.0.html

Good luck to you.

That helps a lot, thanks a bunch.

[bryanj]

Yes, if you master cyl works and you can bleed the system

[Stev-o]

There is also the "compressed air trick" which can be more fun and less messy that the "grease gun trick", albeit a little dangerous!

[bryanj]

Compressed air frequently fails, never had grease gun fail yet, biggest mistake of most people is removing caliper before using master to pump piston out

[Godffery]

 I've got a rebuilt one if you want to go that rout.

[MTNman]

Compressed air frequently fails, never had grease gun fail yet, biggest mistake of most people is removing caliper before using master to pump piston out

Yep I made that mistake as well, and I also tried the compressed air procedure as detailed in the service manual. It didn’t work for me either.

So far I’m working on getting new seals to pump out the cylinder. The front brake was super rough when I bought the bike.

[MTNman]

I've got a rebuilt one if you want to go that rout.

I’ll keep that in mind if something goes very wrong lol. Thanks!