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Old 02-25-2010, 11:13 PM
stevewaclo stevewaclo is online now
Enthusiast
2008 Altima Coupe
2008 3.5SE Coupe,6sp
 
Join Date: May 2008
Location: Carson City, NV
Posts: 32
Unhappy Brake Issues

ptsurfrider:

Sounds like some terrifying issues with the Coupe! Although you did not ask, here are some unsolicited observations from the local "shade tree" mechanic...me:

For many years, manufacturers have bee doing all they can to cut vehicle weight in an effort to meet increasingly stringent CAFE standards. One of the many areas they have found to lose pounds is brake rotors. As you know, brakes do their job by converting the kinetic energy of a moving car into heat and as long as that heat is continually and evenly dissapated, all is usually well. The quite thick (and heavy) rotors of years gone by had adequate mass to absorb and then dissapate the heat under most circumstances (see brake fade). When rotors were lightened, ventilated rotors, like the fronts on just about all cars now, helped considerably as well, by allowing more cooling air to flow within the rotor.

It's my understanding that warpped rotors happen under primarily two major circumstances: the first is when lug nuts are not properly torqued, causing uneven forces on the rotor that are amplified when they get hot, and later as they cool. Since you lost all four rotors, I'm going to rule out that option.

The second circumstance also relates to the heat issue and I'm wondering if something in the ABS/Stability Control System is malfunctioning, causing the rotors to drag more than they usually do and overheat. When you park, the area of the rotor covered by the pads will cool much more slowly than the exposed portions, and here comes the warping effect. (BTW, I mentioned drag, and yes, pads in a disk brake system actually do maintain just a very light contact with the rotors...normally not even enough to be noticed or to heat the rotors beyond only the slightest amount). As far as machining warped rotors, it's my understanding that once rotors have seriously warped, there are fundamental metalurgical changes that will quickly result in the problem returning. Guess it depends on who's paying for the repair...manufacturer warranty = machined rotors; customer out of warranty = new rotors. You gotta wonder tho, if machined rotors are probably going to fail again anyway, why bother?

Also, I mentioned brake fade above, and that happens when overheating (dragging?) rotors/pads/calipers get so hot they boil the brake fluid, causing bubbles in the lines and...no brakes. Sound familiar? Notice any funny smells?

Just some things for you to think about and research further.

Finally, our '08 3.5 SE, 6sp just clocked 25k and looks runs like the day it left the dealer. In fact, we're leaving Saturday for a Vegas/Grand Canyon/Page and Sedona, AZ vacation. My only gripe has been with the Bridgestone Turanzas, that will be replaced when we return. Wear bars in sight.

Best wishes on a happy outcome...and don't let'em tell you "they all do that". Cuz they don't. Nissan makes a great product (and three taps on the START button will shut them off every time! Sorry, Toyota).
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