I am interested in buying a particular '93 240sx, but the owner stated that there is a constant screeching sound coming from the rear. It sounds similar to worn brake pads. He had it checked out and the rear brakes were fine. But according to a mechanic friend and here, he said that this problem was related to having too much tension in the rear calipers from the emergency brake.

After some searching and reading, I've read that the emergency brake is self-adjusting. Is there anyway to manually adjust this?

Could this be worn bearings? Although I believe worn bearings produces whirring sound.

Or perhaps the brake pads could use some anti-squeal on the the back of the pads.

I know it is rather difficult to solve a problem over the internet, but I am looking for some insight as how to attack this problem.

i do believe the cable has somewhat of a manual adjustment, I remember seeing a nut/bolt kinda deal by there the cable splits from one to two. I think it was under the backseat area. It's kinds of like the adjustment of brakes on a bike. You might be able to get under there with a couple wrenches and try backing it off.

the adjusting nut is located under the handle for the parking/emergency brake. Just pull up the handle and stick a allen wrench in there and adjust. The sound could be caused by the brake dust shield on the backside of the rotor, maybe somehow it got bent and is rubbing on the rotor.