This morning my car was driving and stopping okay, then the brakes started dragging worse and worse, until after only a few miles it was impossible to move the car. Pedal was impossible to push down at all. After a few hours, I started it up and it seemed to have fixed itself. Does this sound like a caliper is sticking, or brake pad is dragging until it heats up and expands so bad it stops the car? I changed booster recently but I'm pretty sure it is not the problem because if there was something wrong with it I think it wouldn't have worked ok for a few miles. Thanks for any help

Yes,I would say it's the brake Caliper (replaced in sets of 2).Might as well do the job right and replace all four (Autozone has them for a resonable price).

Or could also be a bad brake hose to the caliper. They go bad and can act like a check valve allowing fluid into the caliper but not out..
After you let it set the claiper is either cooling down and freeing up or the flluid is draining back out the hose.

When you replaced the booster did you readjust the brake rod....It sounds like the replacement booster is shorter or lacking the firewall seal causing the master cylinder to pump up and being too long will not allow the master cylinder to release pressure

quote Originally posted by bigals: When you replaced the booster did you readjust the brake rod....It sounds like the replacement booster is shorter or lacking the firewall seal causing the master cylinder to pump up and being too long will not allow the master cylinder to release pressure

if the pushrod was little too long, could that cause the delayed problem? (car drives ok for several miles before the brakes start locking). what do you mean by firewall seal - that white plastic tube thing? I did use that. . I did the S10 booster upgrade and I was pretty careful to make keep the pushrod same size as the original but anything's possible, I may try couple of washers where booster mounts to see if shimming fixes problem in case pushrod is too long. thanks

Since you say you've recently replaced the booster and/or master cylinder, that would have to be the primary suspect.

Step 1 is to determine if the brakes are dragging on all 4 wheels or just one. If it's all four, then the brake booster and/or master cylinder installation is the likely cause. If only one wheel, then a bad brake hose seems most likely.