2002 mercury grand marquis rear brake pads and parking brake shoes 135,000 miles

auto mechanic told us the rear brakes need replacement. I inspected the rear brake pads and found 3 out of 4 were in excellent condition. The forth was ground down to the metal. I assumed that the slipper needed cleaning. After removing the caliper, I inspected the slipper, the caliper locating bolts, and caliper rubber bushings. All were in excellent condition. The metal under the slipper was a little rough but I did not think it would affect the brake pad movement. I wire brushed the area under the slipper and then installed the slipper…

I measured the disc run-out and it was within specifications but I could see that the disc that had been in contact with the metal in the brake pad needed to be resurfaced. I removed the rear brake disk and discovered that the parking brake shoe linings were in very bad condition. I took the discs to the auto parts store and they could not turn them [0.54 inches on my disc; minimum 0.51 inches] Ford says to resurface the disc on the car with a special milling machine and not to turn the disc off the car on a lathe. So I bought new rear discs.

Do you think I should replace the caliper on the side where the brake pad metal has been in contact with the disc? Would a faulty caliper fail to release from contact with the disc when the brake pedal was released?

Please advise

Answer to question 1) yes.
Answer to question 2) yes.

Be sure you bleed the system and properly adjust the parking brakes.

Sincere best.

Quotiing @LKV2 Would a faulty caliper fail to release from contact with the disc when the brake pedal was released? -

A faulty brake hose can also cause a brake to “hang up”. It’s far more common than a bad caliper.

When I started this brake repair, I discovered that the driver side parking brake cable was disconnected from the driver-side parking brake lever. I have purchased new calipers and brake hoses. I have installed new parking-brake, brake-shoes and new brake discs. The brake disc is combined with a parking brake, brake drum that covers the parking brake shoes. I cannot get the parking brake cable connected to the parking brake lever on the back of the brake backer plate. There is a cable retaining spring and clip that are very strong and it prevents me from making the connection between the cable and the parking brake lever. I have used the ‘parking brake adjuster clip’ to release the tension on the parking brake cable. I want to disconnect the front parking brake cable and conduit from the rear parking brake cable and conduit at the cable connector to determine if the rear parking brake cable is moving freely. There seems to be some tension on the parking brake cable. Is there a special tool used to disconnect the cable connector? Is there a specialized tool to compress the cable retaining spring so the retaining clip and the rear cable can be installed? Please advise.