New master cyl. Calipers, and rear cyl. Bench bled master cyl. And all 4 wheels; no air. Now, must pump brakes to build pressure then once released wait 2 seconds and the pedal goes back to the floor. If I pump the brakes up, the pedal will hold pressure and not sink to the floor unless released, once released it goes straight back to the floor and you have to pump again. Any ideas?
We have opened all bleeders and applied quick pressure to pedal and get a good solid stream out of all wheels. We have run 3 qts of fluid thru it bleeding the system. There is some sort of abs module on the frame rail passenger side as well as the load proportion cyl. Above the rear diff. Bled both of these as well and no change. As I said the pedal will hold pressure if held down after pumping but loses pressure almost instantly once you let it up. Don't think there could be any air in the lines. Anything else?
December, 20, 2012 AT 12:47 AM
Try blocking off each wheel with plastic pliers on the brake hoses. Do all of them and see how the pedal is. If it is good, then release one at a time and when the pedal falls, thats where the problem is.
If the pedal is still bad with all blocked off, bad master cylinder
December, 20, 2012 AT 1:00 AM
IF THAT AIN'T A WORKIN'---WHAT ASEMaster6371 JUST SAID
BEFORE YOU RUN OUT A BUY A MASTER CYLINDER
PLEASE EXPLAIN "EXACTLY" HOW Y'ALL ARE DOIN' THE BLEEDING PROCEDURE