agassiz51

The brakes on my 1987 F150 just started acting strange. The pedal feels softer than before and as pressure is increased will grab with an audible thunking. Truck is driven infrequently but never displayed this problem before. Any thoughts on what could be the cause of this? Any suggestions would be appreciated.

AK Outlaw

Same thing is happening to me at this point. I bled my brakes and it didn't fix the problem.

bcboy92

Did you check to see if your rotors are warped?

planehunter

Sounds like parts are broke or hung up.

Chevy luva

the same here. its been going on for about2 years. no worse no better. cant bleed the front passenger side. the clunk is loud and can feel a slight vibration with it. feels like its about halfway of the ride of the brake pedal and sounds like its on the firewall but can never duplicate when with a mechanic. as well as clicking in the drivetrain somewhere thats matched by speed. spongy break pedal improved with replacement of front disc and pads / bleeding drivers f/r and pass. r. still spongy but always had plenty of breaking power to lock up wheels on dry pavement.

Warlockk

Have you checked the rubber brake lines.

qdeezie

Sounds like RABS Valve or RABS Module

Chevy luva

Do you mean rear abs valve or module?? If so where and how?? Excuse my lack of knowlage

1996 Redneck F150

I had a busted brake line when my brake pedal would do that. I wasn't losing any fluid either. It was kinda weird.

Star98

I just went thru this with mine and it was the ABS mod its on the inside of the driver side frame rail all idid was bypassed it and now they work fine