Hersheybar123

Looking for some help with a brake problem. Here's the shortish story:

-Went to a bad shop with a minor problem, they replaced the brake booster

-the pedal after the replacement was changing from being mushy to very stiff all the time

- went to a good shop with a trustworthy mechanic because the other shop was just wanting to do more "repairs"

-basically, the brakes were sticking and i could smell a burning rubber smell and sometimes see smoke from the tires if i drove enough. Also, the rims would get very hot and the car would slow down going downhill

-the new shop bled the brakes properly (other shop didn't) and replaced both front calipers and brake pads, replaced all hoses.

-STILL, the brakes will "lock up" if i drive for more than a few minutes, the car will start dragging and once i let off the gas, it immediately starts coming to a stop, slowing down going down hill, still getting burning smell and front tires getting very hot

This has been going on for almost a month and it appears to all stem from the initial brake booster replacement. I'm now out almost 1,000 dollars and I still have the same problem. The new shop is going to replace the master cylinder for free. Could this be it? The brake pedal gets very stiff while driving when the car starts getting the dragging feeling. Any ideas? I would really really appreciate it.

-Dave