72 brake issues

[72chevylwbmo]

Now to the next problem. Brakes. I put all new brakes, bearings and seals up front. Went to work on the rear and there isn't any brakes back there. Tried to bleed them and I don't get anything but a drip out of the bleeder screw. You know how when you bleed the brakes and you pump them up, hold, crack open the screw that the pedal goes to the floor. Mine doesn't. So my question is, is it just bad wheel cylinders or could it be the proportioning valve is bad? I have also put on a new master cylinder and booster.

[72bowtiestepper]

Your prop valve has to be "centered"...so the brake fluid goes to both front & back lines. Yours is prob.in the front only position.

[67c10rustbuket]

I had a similar problem when I got my truck and it turned out to be the front to rear steel brake line was clogged and I had to replace it. I removed the rear brake lines and the tee and pumped my brakes and got nothing.. replaced the steel line and was back in business. I did not have to worry about the prop valve though being a drum/drum truck originally. Something else to consider..