Monday, I installed a new set of rotors, pads, and a pair of 3/4 ton front calipers on my '99. Bled the air out of the lines, had good pedal, then started the truck and the pedal went to the floor.

Can't pump up the pedal with the truck running, it will go to the floor with zero resistance. With the truck off, the pedal gets hard and won't go to the floor, although it doesn't feel 100%.

The calipers are installed on the correct sides with the bleeders facing upward. I did not leave the system open for an extended period of time, and the master cylinder never went dry.

I did go ahead and replace the master cylinder and the lines from the master to the proportioning valve and have the exact same pedal as with the old master. The master cylinder was bench bled prior to installation.

I have good fluid pressure coming out of each bleeder. Since Monday, I have gone through 3 quarts of fluid bleeding the brakes (properly).

Right now I'm at the end of my rope. I have plenty of experience with brakes, but this is throwing me for a loop. Any ideas?

 

They *should* eventually pump up....... Did you bleed the rears as well?

 

Yes, the rears were bled several times as well following the proper order (RR, LR, RF, LF).

The pedal won't pump up even a little with the truck running. You could pump it all day and it will just go to the floor.

 

Just curious, did you hook the vaccum booster line back up?

 

Yes, the booster is hooked up.

The only thing "different" is the 3/4 ton calipers. I've read about plenty of people doing this, physically the calipers bolted right on with the 2500 pads and the only difference was the larger piston. I'm wondering if somehow this is my issue.

 

Nope, won't have anything to do with it.

Is brake, or ABS lite on?

 

Nope, no brake or ABS light. They came on once or twice during the bleeding process but went back off on their own.

 

All I can suggest then is just to keep pumping...... it may take a bit, but, it *should* pump up.

 

Nope. Even bought a vacuum bleeder that hooks up to an air line. Went through another quart of fluid and I still have very little pedal.

 

How is the adjustment on the rears?