Hey everyone hope you are all safe. I went to the mechanic today to change my rear brake pads and rotors after finally driving the car again. When the mechanic took the pads off the top portion was basically untouched and the bottom was completely gone. He mentioned that it has something to do with the caliper but I didn’t really understand him. I did notice that the part of the brake pad that was left wasn’t making contact with the rotor. Does anyone know what is causing this? Attached is a picture of the worn brake pad.

 

The rear sliding calipers are notorious for seizing and causing pad drag. You can replace the seized caliper, grease up the slide pins like your pad life depends on it, and they'll probably last for a while. After my 2nd replacement caliper started to seize I upgraded to OE Brembos.

 

From the looks of the pad wear, the brake pads wan't sitting in the caliper bracket flat.
As MooseLucifer mentioned, it could be the slide pins (the caliper 'floats' on two pins allow for pad wear/movement) weren't lubricated. I use silicone paste on brake caliper slide pins without any issue, as brake caliper grease seems to dry out. I use that grease on the pads.
Could be a few other things:
-brake pad jammed/binded up in the caliper bracket either from incorrect installation or lack of caliper grease
-metal pad shims weren't installed correctly
-brake caliper itself is freezing up.
Check the slide pins, make sure they aren't bent.

 

I think that’s the issue too. My mechanic mentioned that the pins on the caliper were stuck tight and he did something to them with a grinder. He also greased the pins really well. Hopefully this fixes the problem. Do you know anywhere where I can buy affordable calipers? Thanks for your help.

 

My mechanic mentioned that the brake pads were too tightly sandwiched between the calipers and the rotors. When he installed the new brake pads he said it had to be somewhat loose so that the brake pads will work correctly. Will this cause any side effects. It’s my first time owning a car so I don’t know much. Thanks for your help.

 

Yeah, if the pads were jammed into the caliper bracket, that could cause the binding. Could be from manufacturer defect or improper installation.
There should be a little free-play for the pad to move in the bracket. The only concern if they are loose is some noise or rattle, but if he installed the correct pads & hardware there shouldn't be an issue. Happy to help!

 

All good advice above. The pads should be pretty darn tight in the caliper once you get them installed, and once you press and release the brake pedal the pads should be very tight to the rotor. The problems only occur when the pedal is released and there is still pressure forcing the pad into the rotor, but if installed correctly you will not be able to tell the difference by hand. Best way to identify pad drag is to take your car out on the highway for a few minutes, then pull off the highway normally (slow down at a regular pace), pull over, and place the back of your hand near the center of the wheel (wheel will be hot, rotors will burn you). You should feel a decent amount of heat on each of front wheels, significantly less heat in the rears, but regardless both left and right sides should feel about the same. If one side is noticeably hotter, that side is dragging, and if the rears are anywhere near as hot as the fronts, they're both dragging.

As Andrew mentioned above, you should apply anti-squeal to the back of the pad, and you should apply a light amount of grease on the three sides of those little ears on either side of the pad, since they need to slide in the caliper as well. Also double check there are no burrs/obstructions in those little ear channels on the caliper.