I have an '87 3/4 Chevy. On the ride home from work today both calipers locked up pretty good. I could smell something burning and the steering wheel was pulling big time when the brakes were applied. I got home and felt the hub, it was HOT and there was smoke coming from the calipers. I am guessing that brake fluid is not being allowed to return from the caliper. Wouldn't he cause of this be that pressure valve thing that is bolted to the frame under the truck and has all the brake lines coming out of it? How do I determine if this is the culprit or not? <br>Please help! If that is the problem the dealer wants 55 bucks for it.