brake troubles

[mikeyboy1]

I'm working on a barn find 76 cb750 super sport.both front & rear master cylinders are frozen,rusty.front wheel cylinder is not much better would be happy to rebuild them all if I could get them apart.if not ,I need to find new/used ones. any help out there? thanx
Mike

[motogrady]

take the bleeder screw or hose connection off, find someone with an aircompresser,
shoot compressed air in it, the piston should pop out.  If it doesn't at first, tap gently
for a bit, air again, that doesn't do it heat the caliper with a propane torch a bit, air again.

[mikeyboy1]

tried air-no good. theyre pretty bad.any ideas where to find replacement masters without breakin the bank?

[motogrady]

Look on ebay, some Chinese guy is putting up new replacements for a real good price.