rear disc brake problems

[Don Bishop]

I'm having problems bleeding the rear breaks in my 1978 corvette, has no leaks in lines, installed new master cylinder[ bench bled before installed] tried manual bleeding and vacuum bleeding but still getting large air bubbles in fluid,can the caliper pistons be letting the air leak in? Help...

 

[mytoy]

bleeding rear brakes

I had a similar problem, what I did was loosen the bleeder let them bleed themself overnight, the centrifugal force will force the fluid out, attach a hose on the bleeder and let it bleed into a bottle, hope this helps you

 

[clar2001]

yes your caliper can cause this and does, the piston O-rings pass air if you did your brakes and master you might as well spend the bucks and do new calipors and don't forget the old rubber brake line these brake down from the inside and cause proplems , your brakes are no place to try to save money.............

 

[sac001]

One more thing...

The rear calipers have two bleeder screws each. Bleed the inboard bleeder first, and once that is clear, do the outboard.

I had the same problem doing mine, but when I did the inboards first, then the outboards, it worked out fine.

Steve

 

[GTR1999]

You might very well have rear rotor runout which will cause the calipers to pump air into the system. You start out with tight brakes then a short time later have a spongey pedal.Were the rear rotors ever turned? You can tell if the rotor rivets were removed. You need to use a dial indicator on the rotor and rotate it by hand 360* to see what you have for runout. You should do this with the 1/2 shaft disconnected so you're only spinning the rotor. anything over .003"-.004" and you'l have problems. If the rotors are correct the stock lip seals in the calipers will work.