odie
May 18th, 03, 11:31 PM
Not specifically Chevelle, but Chevy drivetrain:
Having brake system bleeding problems on my friend's 46 Ford Coupe street rod. The car's brake system worked fine several years with a dropped axle & full size GM disc/drum brake setup, Granada power brake booster, & Granada power disc/drum master cylinder. The system did not have a proportioning valve & worked fine without it. This Spring he pulled the straight axle & replaced it with a Mustang front end. He also purchased & installed a new "big brake kit" from ECI which turned out to have what appeared to be the same full size GM calipers & rotors that were previously on his straight axle. He plumbed a new line to the front brakes & left the rear intact. He also installed new rubber hoses on the front, making the front brake system on the car all new. When he made his first attempt to bleed the system, he noticed that the fluid "gelled" & some of it floated in the top of the reservoir. Since the car was built by someone else, he thought that either the fluid had drawn moisture or was synthetic fluid & he had added DOT 3. He then completely flushed the system & refilled with DOT 3. We bled the brakes & achieved a decent pedal about 2" off the floor, but when he started the car & the power booster vacuum became operational, the pedal goes all the way to the floor. Thinking "master cylinder", we bled the master cylinder while hanging on the firewall using the brake pedal & a MC bleeding kit. Still the same problem. This time we disconnected the booster, bled the brakes again then did a driveway test. The right rear (of all places!) was the only brake that tried to function. When we reconnected the booster the pedal went to the floor & barely braked the same right rear only. He's on his 3rd MC now, on the last 2 we gravity bled first for a few hours, then pumped fluid using the pedal out all of the corners until a steady stream came from all bleeders, then rebled the 4 corners. Still have the problem. When pumping up the brakes to develop pressure for bleeding you can hear & see the caliper clamping the rotor, but doesn't work on the driveway test & still goes to the floor after you start the motor. We are about to pull our hair out (& believe me, we don't have that much to spare!). We have essentially the same calipers as we had with the same plumbing we had when things worked well before the crossmember install. The rear brakes are unchanged. Is it possible that the MC's are/were all bad? His original was fine until we tried to bleed the system. Was it OK to bleed the MC while on the car using the pedal? How would having the power booster hooked up versus unhooked cause the vast difference in the pedal? Thanks in advance for reading all of this & any ideas you all might have.......... Odie.
Having brake system bleeding problems on my friend's 46 Ford Coupe street rod. The car's brake system worked fine several years with a dropped axle & full size GM disc/drum brake setup, Granada power brake booster, & Granada power disc/drum master cylinder. The system did not have a proportioning valve & worked fine without it. This Spring he pulled the straight axle & replaced it with a Mustang front end. He also purchased & installed a new "big brake kit" from ECI which turned out to have what appeared to be the same full size GM calipers & rotors that were previously on his straight axle. He plumbed a new line to the front brakes & left the rear intact. He also installed new rubber hoses on the front, making the front brake system on the car all new. When he made his first attempt to bleed the system, he noticed that the fluid "gelled" & some of it floated in the top of the reservoir. Since the car was built by someone else, he thought that either the fluid had drawn moisture or was synthetic fluid & he had added DOT 3. He then completely flushed the system & refilled with DOT 3. We bled the brakes & achieved a decent pedal about 2" off the floor, but when he started the car & the power booster vacuum became operational, the pedal goes all the way to the floor. Thinking "master cylinder", we bled the master cylinder while hanging on the firewall using the brake pedal & a MC bleeding kit. Still the same problem. This time we disconnected the booster, bled the brakes again then did a driveway test. The right rear (of all places!) was the only brake that tried to function. When we reconnected the booster the pedal went to the floor & barely braked the same right rear only. He's on his 3rd MC now, on the last 2 we gravity bled first for a few hours, then pumped fluid using the pedal out all of the corners until a steady stream came from all bleeders, then rebled the 4 corners. Still have the problem. When pumping up the brakes to develop pressure for bleeding you can hear & see the caliper clamping the rotor, but doesn't work on the driveway test & still goes to the floor after you start the motor. We are about to pull our hair out (& believe me, we don't have that much to spare!). We have essentially the same calipers as we had with the same plumbing we had when things worked well before the crossmember install. The rear brakes are unchanged. Is it possible that the MC's are/were all bad? His original was fine until we tried to bleed the system. Was it OK to bleed the MC while on the car using the pedal? How would having the power booster hooked up versus unhooked cause the vast difference in the pedal? Thanks in advance for reading all of this & any ideas you all might have.......... Odie.