25,000 miles on vehicle, why a loud crunching sound when i back up applying brakes on 2007 Chevrolet Equinox

with only 25000 miles on vehicle and pads appear to have at least 40% life left, why is a crunching sound heard in the morning when applying brakes. i was going to purchase new pads and turn the rotors, but no one has the type of pads needed for this vehicle... are the original pads defective? or the rotors also defective?

by in Long Valley, NJ on March 19, 2010
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3 answers
ANSWER by , March 19, 2010
Possibly the inside pad is worn out and has metal to metal contact 3 different sets are available here www.napaonline.com Brake Pads - Rear, Safety-Stop - OE Ceramic Product Line: Safety Stop Brake Pads/Shoes SS SS8391X $51.99 Brake Pads - Rear, Ultra Premium - OE Ceramic Product Line: NAPA ULTRA PREMIUM BRAKE PARTS UP UP8391X $109.00 Brake Pads - Rear, Adaptive One - Ceramic Product Line: Adaptive One Brake Pads Per Car Qty.: 1 ADO AD8391 $116.00
ANSWER by , March 19, 2010
I would suggest doing nothing. You state that this only happens in the morning, after the car has sat over night and hasn't been driven for about 8 hours. The noise you hear isn't necessarily a defect if this noise disappears after the first few stops. It's due to surface rust forming on the semi-metallic pads. Surface rust that you probably can't even see with the naked eye. There have been issues in past years like yours that have been addressed through technical bulletins at the dealerships that when a customer complains about this type of noise the technician should inform the customer there are other brake pads that can replace those that are noisy but it will effect the mileage performance and they will wear out faster (less metallic fibers in pads). The option was left up to the owner. They aren't defective though. They do what they're supposed to do.
ANSWER by , August 27, 2010
My experience was at 23000 miles the rotors and pads were wiped out on the inside. After replacing them you could hear a grinding sound when driving and turning. After one day of driving I pulled the rotors off and found one that was grooved on the inside already. Upon closer inspection I found wear on the caliper body right at the threaded hole of the bolt that holds the caliper in place. With a small air grinder I ground about .030'' of the casting away over both threaded holes to provide plenty of clearance between the rotor and the caliper casting. The other side wasn't as bad but I did the same to it. Upon inspection after two weeks of driving, found everything to look new again. I believe that the casting being so close to the rotor may be the cause of the brake problems so many people have had with their Equinox's. ****** I purchased rotors and pads at Auto Zone for less than $150 and they had them in stock.