Not Mopar But A Brake Question

We have a church bus, it is a 95 International School Bus with Hydraulic Brakes, Disc Brakes on all fours. We replaced the MC and Booster 2 years or 10,000 miles ago, and replaced all the soft hoses, calibers, pads and rear rotors 175 miles ago.

After the brake job the left rear would smoke quite a bit when the brakes were applied. I took it back the the heavy truck mechanic that did the work and he said one of the reman Rabestos calibers was sticking and had to be replaced. We replaced it, and now the new caliber with less than 50 miles on it smokes, although not as much. This morning I drove it 15 miles and braked about 6 times, and no smoke seen. I drove the same route home and it smoked when I pulled in my driveway. (I pull in my driveway at the bottom of a 1/4 mile hill,) It does not seem to be bogging the bus down, in fact, I can put it in drive and it freely starts to move forward without throttle. Could it be that that side is gripping more than the left? I would not think it would be another faulty caliber.