i have 91 pontiac boniville. driver side caliper doesnt release brake and overheats. whats causing this.?

Question

pads and caliper replaced

Answer 1

Swelled flex line at the wheel? (internal swelling)
Faulty Master Cylinder brake fluid pressure release valve?

ADDED: (troubleshooting)

You need to find out if and/or where the fluid pressure is being held.
1) Pump the brakes, and release the brake pedal.
2) Crack the bleeder on the caliper. Is there residual pressure?
If no, then you have a bad caliper, or hanging brake pads.
If yes, then go to step 3.
3) Pump the brakes back up and release the brake pedal.
4) Crack the brake line/s loose at the master cylinder. Is there residual brake fluid pressure?
If no, then you have a bad flex line.
If yes, then you have a bad master cylinder.

Answer 2

The most common cause to this problem is the front brake hose(s).

Also, calipers can become pitted in the piston's bore, causing the piston to stick in a position which does not fully release the pressure.

Also, I have seen calipers where the person did not properly lubricate the area of the caliper assembly which the caliper slides on. This cause the caliper to bind in a position which applies constant pressure between the rotor and pads.

I would suggest that you replace brake components in pairs considering the age of the car. Replace both front brake hoses and calipers with a new set of pads to start out freash. You can get remanufactured calipers and for this car, they are fairly cheap.

Answer 3

replace the black brake line connect to the caliper I would replace both line and replace brake oil with dot 3

Answer 4

The flex hose has come apart internally, allowing pressure to apply but not release properly.

Answer 5

All of the above are great suggestions. One more question to ask, is the reservoir over filled?

Answer 6

91 Still a life..!!!