This care is non ABS and has the hat type rotors where the parking brakes use pad. Miles = 180,000 and driven most every day. For the past 6 months I've had an on and off problem of the rear brakes smoking. I've cleaned and lubed the abutments for the pads. Then replaced the calipers using new mounting screws. The last time it happened after letting the car cool down I could turn the wheel proving that the both the pad and shoes had released. What is my next step?

 

Can you tell from your inspections whether it's the service brake (pads) or the parking brake (shoes) that are dragging? If so, confine your further checks to the system that is causing the problem.
Check the cables to the parking brakes and make sure they are free to allow the parking brake to release. They can get rusty and hang up. Check all cables from lever to wheel.
Brake hoses can also go bad and cause the caliper to hang up but it's unlikely that both sides would go bad at once.
The fact that you can turn the wheels probably indicates that the pads/shoes wore down enough to be ineffective, not necessarily that they had released.

 

Thanks for your feedback. It appears the pads and face of the rotor have worn the most. I have never used the parking brake. I have now replaced the hoses and bled all four wheels. Using a manual bleed method with an assistant pushing the brake pedal (open bleeder and push down on petal and then close bleeder and release the petal) I bled all four wheels but could not get rear drivers-side from releasing air. I started with the wheel furthest from the master cylinder and rotated and then went back to the rear drivers-side and bubbles still appear during the down stroke of the petal.

Also, with closer inspection the calipers and wheel hub (with the studs) all show signs of overheating. The wheel hub has a purple discoloration. Am I going to experience failure of seals? Should I replace the pads? Thanks.

 

Replace the pads if they are worn thin enough to warrant replacement.

You may be experiencing seal failure now. It sounds like you may be sucking air in on the upstroke of the pedal and for that reason, you have been unable to bleed that wheel successfully. Might want to rebuild or replace that caliper.

 

Thanks again. I think rebuilding or replacing the calipers is a good idea. That may wait until next weekend.