The C-clamp should be placed on the caliper in such a way that it is compressing the piston evenly. If the C-clamp is not positioned correctly, it can damage the caliper piston or the caliper itself.
The C-clamp should be tightened slowly and gradually. Tightening the C-clamp too quickly can also damage the caliper piston.
Do not over-tighten the C-clamp. Over-tightening can damage the caliper or the C-clamp itself.
If you have any doubts about how to properly use a C-clamp to compress the rear caliper, you should consult a qualified mechanic.
It's important to note that some newer cars have integrated emergency brakes, and compressing the caliper piston without taking proper precautions can indeed cause damage. However, the 1997 Ford Thunderbird does not have an integrated emergency brake, so you can safely use a C-clamp to compress the rear caliper.
Here are the steps on how to properly use a C-clamp to compress the rear caliper on a 1997 Ford Thunderbird:
Park your car on a level surface and engage the parking brake.
Remove the lug nuts and wheels from the rear wheels.
Locate the rear caliper. It is on the back side of the rear brake rotor.
Remove the two bolts that hold the caliper bracket to the spindle.
Gently pull the caliper off of the rotor. Be careful not to damage the brake pads.
Place the C-clamp on the caliper so that it is compressing the piston evenly.
Tighten the C-clamp slowly and gradually until the piston is fully compressed.
Be sure the caliper slides and guide pins move freely in their bores and caliper bracket.
Reinstall the caliper on the rotor and replace the bolts that hold it to the spindle.
Replace the wheels and lug nuts. Lower the vehicle.
Now that the piston has been depressed sufficiently, you can depress the brake pedal to move the new pads into contact with the rotor and then retract the piston slightly so the pads can be easily repositioned over the rotor.
Repeat this process for the other caliper and be sure to reinstall the calipers straight onto their mounting surfaces for proper even force between the pads.
Test the brakes by applying them gently at first to seat the pads to the rotor. Then make a few gentle stops to build some heat in the pads for improved effectiveness