One of these days my brake saga will be resolved. So I go to swap out the calipers and Jesus at the parts store gave me the wrong ones. No big deal. Another trip to the parts store and back. When I get back the reservoir has run dry because the banjo bolts leaked after breaking them loose. Get everything bolted back up. Bleed the system. Follow the order of master cylinder, combo valve, RWAL valve, LR, RR, LF, RF. Get clear fluid running through the system. Pedal feels solid. Fire it up, vacuum kicks in the booster, step on the pedal and it hits the floor. Truck stops. I can lock them up, but the pedal goes all the way to the floor. Another 1/2 gallon of fluid for bleeding, no air in lines, pedal feels solid when not running, no air, fire it up and pedal goes soft. I have read a few other threads where similiar incidents have occured, but haven't seen anyone saying what the fix actually was. Everything was working fine up until this. I don't think it is the booster because the pedal gets hard when they go bad. Any ideas?

 

An hour worth of bleeding and about a gallon of brake fluild later, still the same result. The pedal will go to the floor. I am at wits end. There is obviously something that I am over looking. I didn't get any air out of the system at all. By now I have pushed new fluid through the entire system so there can't possibly be any air.

 

Was the master cylinder bone dry when you got back from the parts store or was there "some" fluid left? If it was truly bone dry then you will need to properly bleed the master cylinder before you can even think of moving on to the rest of the brake system. You will need to fill the master and have a helper pump the brakes until they are good and hard then crack the fittings loose one at a time per cycle and bleed them of air. then do the other fitting at the master. When you are done there you need to start at the right rear first as opposed to the left rear that you have been starting with. After right rear then go left rear then right front then left front. Make sure you pump the pedal enough times with steady even pressure with each pump. If you just jab the pedal and there is air in the system you will create many more smaller pockets of air which will require more time to bleed them out. There can always be a pocket of air that gets trapped during bleeding if you don't take the time to do it properly and just rush through it. Good luck and hope this helps.

 

I am thinking it could be the RWAL valve. I found this: http://www.aa1car.com/library/abs_kelseyhayes_rwal.htm

If it turns out to be the RWAL valve, it looks like a $400 dealer part. Considering the silly things have never worked, I wonder what would happen if I by passed the valve?

 

There is a tool for holding the combo valve open available however I believe that you can give the brake pedal one good hard stab with you foot and hod pressure after the initial stabbing of the pedal which is to center the combo valve internally. You could give that a shot.