The rear brakes can squeak because the rear brake pad may be contacting the brake rotor. A burr on the backing plate of the brake pad can prevent the pad from seating in the bracket properly causing the contact with the rotor. The backing plate and the pad support hardware can be deburred in the contact areas. Mazda has also released revised brake pads.Google+
Car Problem Reports
Mazda Mazda3 Rear Brakes Squeaking
Mazda Mazda3 Problem
Average Mileage: 53,557 mi (23,000 mi - 89,901 mi)
Visitor, 2006 Mazda Mazda3
The car squeaks when moving in reverse, from the brakes.
Visitor, 2009 Mazda Mazda3
squeeks when braking in reverse down slight incline of driveway
Took our Mazda 3 in for scheduled maintenance. The service centre said that the break pads, (although only 30% worn, we mainly engine-brake in our manual transmission vehicle), were cracked due to overheating. This seems HIGHLY suspicious to me, to have this problem in a vehicle with only 40,000mi on it that doesn't get driven hard. That is, it's a very rare occasion that we ever hammer on the brakes seeing as we let the engine do most of the braking for us.
I truly believe this some kind of manufacturers default -- which of course, the service centre won't take responsibility for and want us to spend hundreds of dollars to replace them.
Visitor, 2004 Mazda Mazda3, 89,901 mi
Just had front pads replaced, back pads are still at 80%. When I back up, or start out in the morning a very high pitched squeak can be heard....I don't have a clue what it is.
Visitor, 2010 Mazda Mazda3, 70,000 mi
Purchased the car new. Soon after purchase (>200 mi), I noticed a hot, burning smell while driving. At first it was attributed to something burning off of the engine. While driving I noticed that the car was dragging a little bit. When I pulled over and inspected the car, I could feel the heat radiating from the left rear wheel. The brake was not releasing and while driving the brakes would overheat. On subsequent events, temperature was over 400degF (upper limit of my IR thermometer) for more than 10 minutes. Took to MAZDA twice on second attempt the issue was fixed. Soon after, the right-rear did the same thing. Brought to MAZDA and was apparently fixed. At around 70000 miles, on a long trip, the right rear became fully worn, damaged the rotor the metal to metal grinding is constant, and the hot metal fragments coming from the brake components have ruined the finish on the rear wheel. Scheduled for service.
Visitor, 2008 Mazda Mazda3, 23,000 mi
The Honolulu Cutter Mazda dealership was unable to hear the squeaking during their test drive. I find this unbelievalbe and asked them if they took it for a test drive. They said the breaks look fine. If I want them to look further, it will cost over $100 to open it up and look. I have an extended warranty on my car, but the warranty company said that they can't tell me whether a repair will be covered until it is opened up and properly diagnosed. My question is, why would I pay the dealer >$100 to open it up for diagnostics if they couldn't even find the squeal upon normal driving (that I hear every day every time I brake).
When braking, the back passengar side makes a low sort of dragging sound