New to me ‘81. CBXing in Alaska

[JoeInTUS]

I have had some luck extracting master cylinder pistons with bolt extractors. If the piston is really stuck putting the master in a hydraulic press and pushing in on the piston to break it free can help if you cannot get it to turn with the extractor. Once broken free the extractor should be able to twist it out.

If the piston is not pressed in too far, I like to use these stubby extractors since you can put a wrench or a socket on it.

irwin bolt extractor.jpg

[crankwalk]

Thanks Joe. That’s plan b next week I’m thinking.

[daves79x]

However, if you must resort to this procedure, there's a good chance the bore it pitted beyond use anyway. The only fix then is re-sleeving.

Dave

[crankwalk]

However, if you must resort to this procedure, there's a good chance the bore it pitted beyond use anyway. The only fix then is re-sleeving.

Dave

Yeah I’m prepared for that but at this point I just don’t want to be defeated and I want to see what’s in there. I probably won’t get it resleeved but buy a universal one and make it work unfortunately. This bike still needs so much and I don’t want hundreds in the budget to go to a rear master.

[CBX-tras]

Pitted bores shouldn't be an issue as the piston is only in contact with the seal. Pitted pistons, now, that's a problem.

I push them out with pressure either air or grease, depending on how stuck they are.

[NobleHops]

Pitted bores shouldn't be an issue as the piston is only in contact with the seal. Pitted pistons, now, that's a problem.

?? That is not my experience at all.

EDIT!
Ahhhh, Dave turned the lights on for me. JR is talking about a caliper, not a MC.

[crankwalk]

Pitted bores shouldn't be an issue as the piston is only in contact with the seal. Pitted pistons, now, that's a problem.

I push them out with pressure either air or grease, depending on how stuck they are.

I'm a little confused by this. The rebuild kits come with a new piston so I'm not super concerned about that. If the bore is trashed though that's not going to seal well with new stuff. I won't be able to miss with it for another week anyway so in the meantime it's still soaking until I can break away from work.

[jt]

This is how I removed my stuck piston. I think I used a 8/32 screw and nut and two fender washers. Drilled and tapped the piston and screwed the nut till the piston came out.

CBX MASTERCYLINDER.jpg

[Jeff Bennetts]

When necessary, the grease gun method has never failed me!

You spoke of a universal M/C, I saw on the CB1100F site where a ZRX rear M/C was an easy conversion, I have 3 or 4 of them laying around and when time permits I’m going to do a comparison.

That’s a good method jt! Less messy too.

[crankwalk]

^I've ordered one of the cheap $15 ones just to have on standby just in case and I wont fell bad if I have to drill/tap it to make it fit.

That fender washer trick is pretty neat! My bike sat for 20+ years so I know why it seized but since this seems like a fairly common issue, are these seizing on semi-regularly used bikes too?

[jt]

That’s a good method jt! Less messy too.

Thanks, That's what I was thinking to and quicker too !

[Jeff Bennetts]

That’s a good method jt! Less messy too.

Thanks, That's what I was thinking to and quicker too !

And don’t be afraid to put some heat on it, black epoxy paint isn't that expensive!

[daves79x]

After reading over the comments here, I'm thinking we are mixing master cylinder rebuild with caliper rebuild.

Dave

[Rick Pope]

[/quote]
And don’t be afraid to put some heat on it, black epoxy paint isn't that expensive!
[/quote]

A hair dryer would likely be sufficient.

[Jeff Bennetts]

And don’t be afraid to put some heat on it, black epoxy paint isn't that expensive!
[/quote]

A hair dryer would likely be sufficient.
[/quote]

A good heat gun would likely be sufficient, FIFY.