Power Brake Question
Thread Starter
Racer
Joined: Jul 2004
Posts: 352
Likes: 1
From: Minneapolis Minnesota
Power Brake Question
1970. I bleed the brakes several times around and got good pedal pressure. Once I start the car (power brakes) the pedal goes all the way to the floor. I have not taken it for a test ride yet, but feel this is not right, any ideas?
Thanks,
Dan
Thanks,
Dan
Thread Starter
Racer
Joined: Jul 2004
Posts: 352
Likes: 1
From: Minneapolis Minnesota
I'm pretty sure I have all the air out of the system. How is it that I get good solid pedal when it is not running and nothing when it is running? I guess I would like to understand what is going on. Anyone have an explanation?
Thanks,
Dan
Thanks,
Dan
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Vacuum booster. The firm pedal is indicative of a properly operating booster. When you turn on the vehicle, the brake pedal will drop slightly. Like DB said you probably have air in the system. It can be a pita to remove the air and it sucks. Which is why I'm converting to C5 brakes. If you read a lot of posts this is a problem common to C2-C3 vettes. A good design in theory, but shoddy production work in my opinion.
Pro
Joined: Apr 2007
Posts: 736
Likes: 1
From: Chester VA
I'm in the same boat man, I'm gathering parts now to just go through the whole system. Brakes fine, but pedal is real spongy. It drove me crazy. I bled it numerous and I was also positive there was no air-last few times bleeding didn't get a single bubble, but something is still up.
Heel & Toe
Joined: May 2007
Posts: 19
Likes: 0
From: Edmonton Alberta
Try a power bleeder.
I used one for the first time this weekend and it is the way to go.
My petal was never firmer no matter how many times I blead and re bled the breaks.
but I also just installed a new master cylinder, booster, and perporting block, so that could also have something to do with it.....
I ordered it from Summit, was about $75, just less than a case of break fluid :-)
-->Darcy
I used one for the first time this weekend and it is the way to go.
My petal was never firmer no matter how many times I blead and re bled the breaks.
but I also just installed a new master cylinder, booster, and perporting block, so that could also have something to do with it.....
I ordered it from Summit, was about $75, just less than a case of break fluid :-)
-->Darcy
Pro
Joined: Jun 2004
Posts: 700
Likes: 0
From: Lantana TX
My car was on jack stands for 4 months with the exact same problem...trust me I know what your going through and it is fairly easy to test.Here is what I would do:
Disconnect the front and rear lines to the MC and stick plugs in them. Start the car and if the pedal is hard as a rock you know the issue is after the MC, which means you have air in the system. If the pedal is spongy while the car is started using this method then your MC is bad or needs to be bench bleed. Unlikely that your booster is bad for now.
Now if the pedal is hard as a rock while started reconnect both lines and buy 4 C- clamps from Lowes or HD and place them on the rubber lines at all 4 wheels and tighten them. Now start the car and press the brakes again if all is hard then you have air in one of the calip's or all of them. If the pedal is soft you have an issue after the MC but before the calip. At that point I would test the P valve.
Let me know how you make out and good luck.
It is a process, but after 4 months or being stumped along with everyone else on this forum I finally got it fixed
.......and then blew my motor the very next weekend at the track
