My rear brakes dont feel like they are working right, ever since I had a caliper sieze up. Seems like the fronts are doing all the work. I thought I would fined a valve on the frame rail somewhere, but nothing.

The other problem I have is its all over the road when I have to stab the brakes. I have all new Ford dealer supplied rotors, wagner pads, 2 new calipers on the front and 1 new caliper on the rear.

The front is all new ball joints, tie rod ends, shocks, tires, alignment, etc.

Stab the brakes for some idiot stopped in front of you and you dont know which direction its gonna go.

Any ideas ?

 

The brake "proportioning valve" is part of the ABS control. You can find that typically right above the steering gear.

So the braking actions is not consistent to one side only? That rules out the brakes as the culprit.

 

The fronts should be pretty heavily biased. As said it's not a classic valve, it's a module that modulates the pressures as needed.

Maybe the slide pins have seized again?

 

Is there air in the brake line(s)?

 

When you brake hard, does the rear end lock and slide sideways or does it feel like the front is making it pull one way or the other by braking harder on one side?

 

I know the older Superduty's like my '01 with the Kelsey-Hayes ABS unit actually do have a typical modulator bolted to the side of the ABS valve unit. Not sure what the newer SD's use.

Definitely sounds like slide-pins, or something else loose.

 

to me it sounds like there is air in the lines. I would bleed all the calipers and see if you get any air.

 

Its on the 2000 that does this. No, I am not locking the tires up, yes, brake pads and rotors are all fairly new, as well as 3 calipers. It is most pronounced on a firm abrupt stop (driving in city traffic) I have to change the rear end and will change caliper #4 and bleed the entire system. All the caliper pins have been freed, cleaned and grease recently, but it does act like a seized pin. The wow in the braking combined with the wow in the steering makes a dangerous combination.