I noticed the other day while adjusting my tire pressure that one of my rotors is cracked. I recently replaced the stock pads with Adaptive One ceramic pads. I don't believe that the crack is from "wear and tear" but what are my chances that the factory warranty will cover this? If not I'll just replace the rotors and inspect the pads.

 

Don't see how a cracked rotor can be "wear and tear". I would try the warranty first.

 

I agree with posts number 5 and 7. I wanted new rotors but when a car maker won't do it I'll settle for resurface. I use to resurface them and there is a tolerance before they are bad. And in the future I will put on new new brakes and rotors since the car will be out of warranty anyway.

 

do the hhr's have a rear axle brake proportioning valve? i.e. more weight more braking. i had a honda station wagon years ago that had such a valve. the rear brakes didn't work. the fronts were doing all the stopping. i bypassed this valve because the linkage to the axle was completely seized. after that the car stopped much better. question is wether or not the front brakes on the hhrs are doing all the stopping. i.e. more braking more heat..more heat more warpage.. just a theory. a week ago in the snow with the hhr, the fronts locked up but the rears didnt(no abs).

 

Not sure, but a several guys have reported 90K-100K on the stock rear brakes..... Food for thought.

 

Yes there is a proportioning valve, sounds like your rears need a manual adjustment..

Mine did when I removed the drums for brake inspection & painting..

 

All cars have some proportioning valve. Most are mechanical but with todays new cars some are electronic. My GTP Comp G's system will adjust to the weight balance of the car and adjust on the fly.

The key here is your front brakes will always do most of the stopping. When you stop the weight transfers to the front and puts the load ont he front two tires. If you have too much rear balance it could spin out be unstable. I had a Monte with too much rear balance due to a bad valve and it spun on me one rainy day. I was lucky no one was around.

The fact the fronts locked up first is a sign that the system was doing it's job. The last thing you want is the rears to lock first or have too much stopping if most of the weight has transfered to the front of the vehicle.

Most drag cars use chutes to stop as they have too litte tire up front to stop the car. Watch a top fuel car lose a chute and you will see the rear tires lock and hop. Often they hit the sand as they can't stop. The chutes are not for show as they really need them even with todays improved brakes. I cringe every time I see a street rod with only rear brakes. I often wonder how they got them past the safety inspection.

Most cars with rear drums will do up to 100,000 in most cases. Rear disc will often do a little less as the pads are smaller.

More heat and more warpage is not the problem as this is why few people ever solve their problem. To do damage to the front they would have to be glowing red hot.

To mess with the rear brakes is not recomended unless you know what you are doing. To set the balance you really need to know how to set up brakes on a car right. Too much will not only wear the rear brakes more but make for a possible dangerous situation when braking hard. Many of todays systems are also adjusred to be used with the anti lock systems and stability control too. GM has factored this in and has it set better thany most here ever will.

There are much more to brake systems than meets the eye.

 

There is more exposed surface area for air cooling, much like the finned cylinder heads on 2 stroke motorcycle engines, which like you point out, use additional metal. You probably gain about what you lose.
Itried a set of EBC slotted & dimpled rotors, didn't make any difference, didn't last very long either. I replaced with no name Chinese rotors, which have lasted longer. I think the slots wear your pads down quickly, almost like dragging a knife edge over the face.

 

If only the holes did create more air flow but there is not enough air moved to make it really work. To get the air flow needed you would really need air ducts etc and even then it would still be limited. Note most F1, Indy, NASCAR and sports prototypes all use brakes with solid rotors and at best migh have slots just to clean them from rubber and debrie from the track.

I have used the EBC on my GP and they worked find. Not issues and they looked nice. But When I had to put brakes on the last time I just went back to the Bendix solid rotors. They are quieter. I assume in some cases they could wear a little more with dimples but I did not see it.

 

Yes front brakes do most of the stopping, but the rears adjusted 'properly' is also very important..

I think that is why some have front brake problems..