Just changed the rear brakes on my 03 Baja. Drove it to the store and both of my new rotors are eaten up. What would cause this? Master cylinder? Both calipers? Help!

can you describe or post pics of the damage?

any problems during the work?

brake hoses get twisted?

Went smoothly, I have changed disc brakes before. Pistons compressed without any difficulty. I could feel it while driving but I didn’t realize how bad it was. The pads dug into the rotors to the point they may or may not be able to be turned. Just do not want to repeat the problem and don’t really know what to check first

Pads in backwards?

What kind of pads and rotors did you use?

pads installed backwards. 

pictures might help - take pictures of both sides of the rotor before you pull the pad from the caliper bracket so we can see what it's doing.