I noticed that when I drive around and come home, my rear left brake smells of hot metal. Then I noticed that the disc is very hot, while the right one is cold. Also noticed that the right disc is rusting, so the conclusion is that my rear right brake is not working.

All discs and pads are less than 6 months old, so this should not the issue.

For some reason that caliper just isn't pressing the two together and the other brake does all the work

Tomorrow I'm going to take a closer look, does anybody have any ideas on what might be the issue here?

Your caliper is seized. Toyota sells rebuild kits pretty cheap, or you can simply replace the entire thing.

>
^^this, plus you could try to bleed the two calipers through the nipple to verify that they are both recieving hydraulic pressure bfore you go about rebuilding/replacing calipers. Your e-brake could also be dragging, try jacking the wheels off of the ground and see if they turn freely. You could also have a buddy apply slight pressure to the brake pedal and see if they are harder to turn.

like what smaay said. jack up the car and see what the suspect is, use your foot brake and test forward and backward. see which one has the problem. you can also determine if its your handbrake getting stuck and probably your rear brake pads inside the hub are not sliding on the back plate cus its probably rusting. check for hydraulic pressure, check if its actually the caliper needing rebuild or replacement. testing which one is hot or using an thermal gun just tells you which side it is, you have to check on all those things still.

This post has been edited by trdproven: Jan 23, 2013 - 7:48 PM