For about the last week or so my 95 GL has been making a grinding noise from the rear end which I thought was because it needed new pads. I pulled the tires off and inspected the pads. They are warn about 50%. Now I am stuck on what would be making this grinding noise. It seems to do it more when I first drive the car, and goes away within a few minutes. Could it be a caliper piston sticking on me and how would I check for that? The car has 107k on it. I bought it with 74k so I'm not sure what has been done to the brakes. Any info would be great. Thanks