Jim Grant's Tech Tips

'97 Chevy S10, Brake Drag Problems

Q:I have a ‘97 S10 with a 4.3 engine. I have a problem where my front brakes drag. I have replaced (twice) calipers, rotors, pads, pins and brake lines and bled the brakes front and rear. I can spin the rotors freely with the brakes in place, but as soon as I press the brake pedal, I cannot easily (without force) spin the wheels. I thought maybe that the pads needed some miles on them to seat. After 100 miles they were red hot and won't spin freely. What could the problem be? I thought about changing out the master cylinder.

A: This may help to pin the problem down. After applying the brake, open the bleeder screw at the brake caliper. If suddenly the wheels/rotors turn freely you know the problem is up-stream. Apply the brakes again and confirm that the problem has returned. This time loosen the brake line at the master cylinder for the front brakes. If the wheels/rotors turn freely then the problem is with the master cylinder. Apply the brakes again and confirm that the problem has returned. At this point loosen the nuts/bolts that hold the master cylinder to the brake booster. If this causes the wheels/rotors to turn freely it is likely that the push rod from the brake booster to the master cylinder is incorrectly adjusted. If the wheels/rotors still drag then the master cylinder is the problem.