68 Nova Master Cylinder Problems

[fvballew]

I tried to bleed my brakes and ran to problems with the rear brakes. I ended up replacing the master cylinder because brake fluid was not coming out of the rear port on the master cylinder but was going to through the front port for the front brakes fine.

I bought a new master cylinder, completed the bench bleeding process. Put the master cylinder on the car with the same results

Again, I bought a new master cylinder, completed the bench bleeding process. Put the master cylinder on the car with the same results

Anyone have any clues.

[maxwedge]

Welcome to AF, no mention if you have disc brakes, if so the prop valve could be bad, or find the small button on the end of the prop valve and hold it out when bleeding, this will get full pressure to the rear.

[fvballew]

Thanks for your reply. I do not have disk brakes, I have replaced the proportional valve, front to rear brake line, the flex line, blown out the rear brake lines.

What I dom,not understamd is with the brake lines diconnected from the master cylinder, plenty of brake fluid comes oot of the front line port, but very fluid comes out the rear port when the brake peddle is pumped.

[maxwedge]

If you have drum brakes there should not be a proportioning valve, just a junction block.

[old_master]

If you pushed the pedal down with the lines disconnected at the master cylinder, when you released the pedal, it sucked in air. You need to bench bleed the master cylinder with a bench bleeding kit until no more bubbles come out of the lines into the reservoir.