Brakes grabbing....WTF!!$#^%#$&#

[mercuryhead]

I noticed that my brakes will grab when driving the car for a while. If I shut the car off and let it sit for a half hour or so, the problem goes away. I changed out the MC, but no change. I had an '88 Bronco that had a similar problem (proportioning valve solved it). I hope it's not the proportioning valve, Ford in their infinite wisdom decided to discontinue them

maybe the booster?....it seems to be workin' fine though :confused:

Any thoughts on what it might be?....anybody else experience this?

TIA

[P72Ford]

I noticed that my brakes will grab when driving the car for a while. If I shut the car off and let it sit for a half hour or so, the problem goes away. I changed out the MC, but no change. I had an '88 Bronco that had a similar problem (proportioning valve solved it). I hope it's not the proportioning valve, Ford in their infinite wisdom decided to discontinue them

maybe the booster?....it seems to be workin' fine though :confused:

Any thoughts on what it might be?....anybody else experience this?

TIA

After driving the car for a period of time, the brakes will hold, and not release? If you play with the pedal when the brakes are locked on (with the engine off), can you get the brakes to release?

Anyway, we had the same problem with my brother's '88. We redid the entire braking system; from the roota to the toota. It turned out the problem was that last thing we changed; the booster. The diaphragm in the booster may be no good.

My money is on that, because it sounds like you have the exact same problem he did.

[mercuryhead]

After driving the car for a period of time, the brakes will hold, and not release? If you play with the pedal when the brakes are locked on (with the engine off), can you get the brakes to release?

Anyway, we had the same problem with my brother's '88. We redid the entire braking system; from the roota to the toota. It turned out the problem was that last thing we changed; the booster. The diaphragm in the booster may be no good.

My money is on that, because it sounds like you have the exact same problem he did.

thanx for the reply!....Im guessin' the same thing.
I tried to jack the car up to see if just the rears are grabbin'(proportioning valve problem), or all the wheels are grabbing(booster problem)....but by the time I got back to my car(30 min. later), it wasnt grabbing anymore.
When you did the booster, did you have to adjust the push rod on it, or did it come pre-adjusted?

[gadget73]

Last time I had something like this happen it was defective front calipers. Letting it sit for a bit allowed them to cool and release. Collapsed brake hoses can also do this. If your hoses and calipers are original, you might want to consider replacing them just due to age.

[mercuryhead]

Last time I had something like this happen it was defective front calipers. Letting it sit for a bit allowed them to cool and release. Collapsed brake hoses can also do this. If your hoses and calipers are original, you might want to consider replacing them just due to age.

it would be odd to have both front go at the same time tough.........and the car doesn't pull to one side, it grabs evenly. Hopefully tomorrow I will know for sure when I jack up the car to see if it's just the front, just the rear, or all around.

[gadget73]

i had a bad caliper, replaced it, and the other one went bad the next day. anything is possible. if those caliper slider pins have not been lubricated for a long time, that might be it.

[CheeseSteakJim]

Yeah, when/if you change the calipers don't forget to dip the end of each slider pin into some synthetic brake grease.

[P72Ford]

We also thought it was the calipers (or rear wheel cylinders) on my brother's '88. When the brakes used to stick on, it was all of the brakes that were applied. We jacked it up, and upon trying to rotate the wheels, realized all the brakes were stuck. But, after we replaced everything else in the system (except for the booster), it still wasn't fixed.

[mercuryhead]

UPDATE!
Gadget was right, bad calipers/hoses.....Thanx for the input.....thanx to everybody!
I jacked up the car and the rear wheels moved fine, but the fronts were sticking. The driver's side was sticking alot and the passenger side was sticking only a little. Tomorrow Im gonna pick up some new calipers and hoses.

Yeah, when/if you change the calipers don't forget to dip the end of each slider pin into some synthetic brake grease.

I usually use castrol wheel bearing grease, but tomorrow Ill see if they have synthetic brake grease at the parts store.

[CheeseSteakJim]

DON'T use any petroleum based lube on them. Petroleum breaks down rubber. Use synthetic brake grease.

[gadget73]

The wheel bearing grease also won't hold up to the temperatures brakes run at. it will thin and run out.

[mercuryhead]

ok......thanx for the heads up. I will for sure buy some synthetic brake grease.

[ss_mini14]

i had a similar problem about 2 months ago and it was in the rear drums. the cable for the left rear self adjuster had broken sometime in the past and eventually the star wheel assembly fell out, bounced around, broke a brake shoe, and ground itself into oblivion while making the most horrendous noise and dragging like it was trying to till solid rock. now i know why the left rear never locked up.

[mercuryhead]

I did the calipers and the hoses on Saturday and all is well, except that the front pads are noisy(grinding) now on heavy braking. I left the old pads on, they were practically brand new.