95 GT Brake Problem

Brake Problems with 1995 Grand AM GT, V6 3.1 L, automatic, ABS.
A complete brake job was done on this car just recently : pads/shoes,
front disks were replaced and rear drums turned. The problem occurs when I stop at a light etc. When I take my foot off the brake pedal and start accelerating, there is a clunk coming from the rear wheels and the car feels as if the brakes are locking up and then releasing. I went back to the garage that did the work. They "adjusted" the rear brakes. It was fine for about a day, then it started doing the same thing. I went back to the garage a second time. They test drove the vehicle and inspected the brakes but could find nothing wrong. The problem was still occurring especially in very hot weather,after driving the car for over 1/2 hour or so. I went back to the garage and they changed the rear brake shoes, telling me they may have been "defective" . The car was fine for about a week. Now it's doing the same thing again. I also notice that if I apply the brakes while going downhill, the car shakes quite a bit and I can feel it on the steering wheel. I don't know if both problems are related. Any help is appreciated. Thanks.

Almost sounds like the drums were turned uneven or they are dragging inside the drums. and the shaking in the front kinda sounds like warped rotors. it is very Rare to get defective brake shoes but I have had shoes(new) fail. I bought Autozone rotors and pads for the front and about a week later I was on the highway and braked to catch the offramp and I heard something hit the inside of the front fender and I stoped down the road a looked, the damn pad came off the metal plate they were attached to. screwwed up the new rotors real good! I took them all back they hooked me up good! a great deal on some slotted/drilled rotors and carbon metalic pads. They pretty much just swaped the junk ones for the more expensive ones. I had to buy someother peices and pay the tax, but i wasnt bitchin. I do spend 1000-2000$ a week on auto parts,not just Autozone, thats why they were so generous with me:) Good Luck!

The clunk in the rear sounds like one of the shoes is hanging up on the backing plate, make sure the place that did the brake job greased the plate before the shoes were put in. As for the shaking, I agree on bad rotors, possibly caused by improper torque on the front wheels when they were put back on.