Rear MC compat question..

[Guest]

Ok so ive rebuilt my MC once...rebuilt my caliper twice..still sticking...replaced rear caliper..dunno if thats going to do the trick yet, but my question is this..
I have a rear MC from a 80 750..its a lil different resivour set up than that of the 77 that i have, but will it work for the 77? i know ill have to figure out a way to wire the resiviour and hose upright..but should it do the trick? Thanks!
TCK

[chef1366]

In the master cylinder there is a tiny hole which is the return line. If this is clogged the caliper will stick.

If the bores of the old caliper were ovaled out this would also cause the issue but they would most likely leak.

Is the spring on the lever returning the brake pedal all the way back up?

[TheCafeKid]

It seems to be, and i cleaned out the return on the MC...twice...lol It was in pretty bad shape, lots of rust and crap in it, i used a new rebuild kit, but it lasted a few days and started to do it again. Is that other MC not going to work?

[chef1366]

It seems to be, and i cleaned out the return on the MC...twice...lol It was in pretty bad shape, lots of rust and crap in it, i used a new rebuild kit, but it lasted a few days and started to do it again. Is that other MC not going to work?

Don't know. Sounds like you need to completely flush out the old units and get them to work. PITA but I bet it will work.

[Ironriot]

Don't know. Sounds like you need to completely flush out the old units and get them to work. PITA but I bet it will work.

Agreed. Run brake fluid through that bastard till it runs clear. Which mind you might take an entire bottle. My rear brake had some pretty bad rust in it. I just bleed a whole bottle throught the bleed valve till it was running clear. Works like a charm now. PLUS my wheel spins freely! Big improvement over it only spinning a few inches

[tone]

Ok so ive rebuilt my MC once...rebuilt my caliper twice..still sticking...replaced rear caliper..dunno if thats going to do the trick yet, but my question is this..
I have a rear MC from a 80 750..its a lil different resivour set up than that of the 77 that i have, but will it work for the 77? i know ill have to figure out a way to wire the resiviour and hose upright..but should it do the trick? Thanks!
TCK

Yep same piston size & same caliper originaly so it will work fine :-D

[Billy Ricks]

The '80s models use the same m/c as most GSXR models.

[spchips]

I've cleared stuck ones by bleeding down through the bleeder till it runs clear, then using compressed air on the bleed hose to pop the return free. Be careful not to put more air pressure than the bleeder nipple/hose interface can sustain.