Hello. I have just installed a hydroboost system in place of the old booster and now I can't get the rear brakes to bleed. Here is what I have done so far: I thought it might be the combination valve so I took it off and cleaned it real good with Brakekleen. Put it back on and checked to make sure fluid is coming out the port that feeds the rear and I seem to be getting good flow. I then disconnected the brake line that goes to the right rear wheel cylinder and blew compressed air into the line that comes out of the comb. valve, that feeds the rear. Got a bit of fluid out of the line back by the wheel cyl. Hooked that line back up to the right rear w/c and then disconnected the brake line that goes to the left rear w/c. Blew that guy out with air and did get some fluid that time also. I then hooked this line back to the w/c and tried to bleed but got no fluid out of the right or the rear. Must be some blockage in the rear someplace. Any suggestions? Appreciate any help you guys can give me. Thanks.

how old is your brake hose? they deterierate with age & restrict fluid. tahe it off and blow throu it, it should be open enough to free-flow.

Open the right rear bleeder and with a finger held over the hole on the bleeder. Have someone inside pump the pedal several times. Fluid will push out your finger but air wont get in because your finger is held against it preventing it from entering back in.

Then go to left rear and do the same thing.

Chris.

You probably have a clog in the line going to the back, either the long line or the flex hose. I just posted about this a couple weeks ago. After installing my Hydratech hydroboost, my back brakes wouldn't bleed. It turned out the rear flex hose was plugged solid.

MIKED70MALIBU, ALOT OF US HAS EXPERIENCED THE SAME THING YOU ARE, GO TO YOUR LOCAL PARTS STORE AND GET A $30 PUMP CALLED MIGHTY VAC, I THINK YOU'LL FIND YOUR BRAKES TO BLEED QUITE EASY THEN.

Thanks for the suggestions, fellas. I took all the lines off the rear of the car today and blew them out with compressed air. All appear to be free of any obstructions. I will a get Mighty Vac pump, tomorrow, and see if I can get them to bleed.