Looking for an assist here, wondering if anyone has ever seen this. I have a '97 f150 4.2L v6 2wd which of course comes with Rabs. When I first get into the truck the brake pedal has a lot of travel in it. As I continue to drive it becomes stiffer and stiffer with VERY little travel in it. It continues until the brake pads are pressing on the front rotors and heating them up. At this point the truck is struggling to even go forward because its like my foot is pressing on the pedal. I've changed pads, rotors and break lines. Could the abs module be doing this? BTW, after I park the truck and it sits for a while everything returns to normal until I start driving again and the whole process starts all over again.

Any thought would be be greatly appreciated!
Steve

 

Check brake hoses. They could become delaminated inside and work like a check valve.

 

Thanks for the reply. I have already change brake hoses... unfortunately no joy

 

You can temporarily disable the ABS and see if it solves your problem. If it does, then you know it's the ABS system. If not, then you know it's not the ABS system causing the problem.

 

To rule it out
and
Just for GP's try this
What I have found is rust affecting the clamp that holds the brake line (no internal hose damage) on my last 04 with a 4.2
The clamp rusts, and that in turn squeezes on the hose just enough to pressurize the brakes but not release
If your hoses are new, the clamps that hold the hose should not be rusty but take a big screwdriver and release the clamp a small amount anyway

 

Dude that worked like a champ. I can't thank you enough.So it appears that rabs module or the RABS Rear ABS Brake Modulator Valve Actuator is bad. Any way to tell which one?

 

Again just wanted to say thanks.