Why are the brakes locking on the more you use them.

If you have to physically back off the adjusters, shoes are installed correctly. The shorter lining always goes toward the front of the car and the longer one goes toward the rear.

Next time a brake locks up, open the bleeder screw at that wheel or crack the steel line open at the master cylinder. If that lets it release, you have brake fluid contaminated with petroleum product. That will require replacement of all parts that have rubber that contacts the fluid, including seals or o-rings, and the steel lines will need to be flushed and dried. If you leave any part in place that has rubber inside, the contamination will leach out and recontaminate the other new parts. Usually you can quickly identify this type of contamination by inspecting the rubber bladder seal under the master cylinder reservoir cap. It will be blown up and mushy, and hard to put back in place.