Billed $680 for brake work 40,000 miles
 

Does this sound reasonable for rear brakes new rotors and pad and front pads rotors turned.

I thought it was very unusual to need rear brakes when the front still were good for another 10,000 miles.

that's alot money. did u got it done ?

That's how I felt. I went to the Mazda dealer here in Atlanta, and they wanted $350 for new pads and machining the front rotors and $550 for new pads and new rotors on the rear. I was getting my 72,000 mile oil change at the time, and that was the first time the brakes had been serviced for anything other than a rotor-turning. And I have 30k more miles than you! I told the dealership the take a long walk off a short pier on the rear brakes because I found the parts I needed to do it myself on ebay for less than $100 while using their wifi. I did take the hit for the front brakes though... what can I say - I am a sucker for the warranty protection.

Actually, the front brakes were $295, but I also got the oil change and I finally sprung the cash for the all-weather floor mats.