I have an SSBC 4 wheel disc brake kit on my 69 Chevelle. The issue is that after approximately 15 minutes of driving, both rear calipers drag hard & it feels as if I'm driving with an E-Brake engaged. I do not have an E-Brake & both are dragging simultaneously so I don't think it would be a caliper issue. Would this be a Proportioning Valve, Master Cylinder or Booster issue? The brakes bleed fine so I'm at a loss. Any advice would be appreciated.

any one ?
Buehler ? Buehler ?:confused:

First Guess: The piston in the master cylinder isn't retracting all the way. The compensating port is blocked. As soon as the rear brakes heat, the fluid expands. The pressure is SUPPOSED to bleed out the compensating port, but with the port blocked--the caliper piston moves out instead. So the brakes get hotter, fluid expands more, piston applies harder...and soon the vehicle won't move.

Pop the master cylinder cover, have someone tickle the brake pedal as you look into the reservoir. You better see two little "geysers" when the brakes are applied. One, or no, geysers mean that the piston(s) isn't retracting far enough.

brake hoses

Try readjusting, shortening, the push rod length to the master cylinder, Also, there are 2 holes in the brake pedal arm - one for manual and 1 for power brakes, power brakes use the top hole for the push rod clevis.

Try readjusting, shortening, the push rod length to the master cylinder, Also, there are 2 holes in the brake pedal arm - one for manual and 1 for power brakes, power brakes use the top hole for the push rod clevis.
All this time I though the upper hole (more leverage) was for manual brakes, while the lower hole (less leverage and pedal travel) was for power brakes.

Are you certain you have the correct master cylinder without residual pressure valve in the rear line ?

hi, are u shure about the pedal holes i have (had ) powerbrakes drums the pushrod was mounted in the lower hole, and shall so be or atleast it says so in the munting instructions (from summit)
/mike

my rear calipers were hanging up "off & on" i pulled the calipers, lubed the bushings & o rings and it cured it.