Brake issues on my 99 taurus, could it be Proportioning Valve

[tommyandamanda21]

Ok good day to you,

I got a 99 Ford taurus, just chenged rear brake pad, rotors, hardware, brake cylinders, and all..

The L/R brake pad on the front half was the only one worn down before we changed them wednesday and that tire is the only tire bald and flat spotted all the way around.

Problem is now when you drive down the road and hit the brake there is this load rumble, rubbing sound and its real noticable and it seems like the only time it does it is when the rear of the car goes up when braking..

any Suggestions , I have pulled brake back apart and put them back on and it still does the same thing....

could it be the Proportioning Valve... its only on the L/side....

[shorod]

I'm a bit confused as to what you replaced. Was it just rear brakes? Do you have drum or disc brakes in the rear? Pads and rotors are consistent with disc brakes, but brake cylinders would indicate drum brakes. Did you replace brake calipers, or rebuild the calipers with new pistons?

Assuming you have rear disc brakes, it sounds like you may have some rust or debris between the hat of the new rotor and the hub. Do you feel the rumble in the brake pedal as well? Did you lightly sand and spray clean the hub before installing the new rotors? Same goes for the front - did you have them apart at all to check them? Even just removing the wheel could allow enough space for debris to get between the rotor hat and hub. Are you sure that it didn't do this before working on the rear and you just never got as aggressive with the braking (since you were probably testing the brakes after working on them)?

If you are braking hard enough for the rear of the car to go up, that's also when you're requesting more of the rear brakes, so they'll grab a bit harder. It sounds like you've got something that's not running true. Rear brake discs are not very thick, so it wouldn't surprise me that if you don't find any debris between the rotor and hub, the new rotors themselves are warped. I've seen it a few times before.

Oh, one other thing to verify - make sure you don't have any grease or brake fluid on the pads or rotors. This could cause a grabbing effect similar to a rumble.

-Rod