I am having a problem with a brake dragging on my 87 base model. The problem occurs when I am driving at highway speeds. I notice a decrease in accelleration and the brake pedal becomes rock hard. I have not been able to determine which brake or brakes are dragging as it goes away before I can get it home.
Does this sound more like a caliper or could it be the master cylinder. Any Ideas ?

 

I'd check for a sticking caliper, or loose or missing retaining spring.

 

I thought it might be a sticking caliper but it doesn't seem to stick when using the brakes and the car doesn't pull to either side. Does this make any sense ?

 

A brake hose that's deteriorated inside will cause pads to hang up and not release.

 

If it was a single brake dragging I would think that it would pull to one side. Also how would they hang up just driving down the road.

 

Anyone else have any ideas ?
I'm really stuck on this one.

 

My guess is there is something going on with the master cylinder. Buy a rebuild kit and rebuild it.

 

I finally determined today that both front brakes are locking up. I think that it must be either the master cylinder or the valve connected to it. I assume this is a proportioning valve. I still don't understand how they can just lockup driving down the road when the brake pedal has not been touched.