just put ront and rear disc brakes on the car..have a corvette style (new) M/C that had been bench bled and a new 7" booster..Vac line is hooked up ...when i bleed the brakes(car not running) i get nice steady streams of fluid(of course after some air bubbles)from the calipers and decent pedal....when i run the car the pedal goes to the floor and the brakes dont hold....any ideas...im missin sumthin simple...thanks in advance
Do you have to bleed the brakes again or is there good pedal after you shut the engine off? If you have to bleed the brakes does one wheel seem to have most of or all of the air bubbles come from it while the others are good? I fought with the wife's ot rig for weeks because there was a bad flair on one of the tubes and while you couldn't see a leak it was drawing air back through the fitting.
First look for a leak, as mentioned. Clean all the brake parts off (water removes brake fluid) so they're nice and dry so you can see any leaks. Then push on the pedal for a while...then carefully inspect for leaks. If the rear brakes have integral parking brakes (in the caliper) also make sure they are adjusted properly.
The Jalopy Journal
