Does the rear caliper piston need to rotate as it

No you do not.

Here is the steps for the brake job and it does not state that other than compressing the piston, you do NOT have to rotate it like on some foreign vehicles:


Removal & Installation

1. Before servicing the vehicle, refer to the Precautions section.
   
2. Drain2/3of the brake fluid from the front reservoir. Use the bleeder screw at the front outlet port to drain the fluid. If equipped with anti-lock brakes, relieve the system pressure.
   
3. Raise and safely support the vehicle.
   
4. Remove the wheels.
   
5. Pry the caliper support spring out of the caliper.
   
6. Remove both caliper slide pin bushing caps and slide pins.
   
7. Lift the caliper from the anchor.
   
8. Using a piece of mechanics wire, support the caliper so there is not tension on the brake hose.
   
9. Remove the brake pads from the caliper.
   

Rear brake pads—Liberty


To install:

1. Position the brake pads onto the caliper.
   
2. Position the caliper into place on the anchor.
   
3. Coat the caliper slide pins with silicone grease and torque them to 18 ft. lbs. (25 Nm). Install the slide pin bushing caps.
   
4. Install the caliper support spring in the top of the caliper under the anchor; then, install the other end into the lower caliper hole.
   NOTE Hold the spring in the caliper hole with your thumb while prying the spring end out and under the anchor.
   
   
5. Fill the master cylinder with fluid and bleed the brake system.
   
6. Before driving the vehicle, pump the brakes several times to seat the pads.
   
7. Install the wheels.
   

by your question I assume that you have disk brakes on the rear? No matter the answer is NO the caliper piston does not need to rotate as it is compressed. It would help to know how many miles you have on your vehicle and if it is a 4x4 do you take it off road much? If so is it common for it to be in the mud a LOT. mike micmor68@gmail.com