Warped Brake Rotors

#1

My wife’s 1999 Olds LS has a problem that has been going on for about 3 years now. Every 8-10K miles, the front rotors warp, and the brakes Pulse to a stop. We have turned rotors until they are too small to true again, replaced rotors with new ones, (3rd new set) and we pay for “The Best Rotors Available” each time. But the same thing happens over and over. Two or three times per year, we have to deal with this. The brake pads NEVER get worn out, calipers move OK, hardware has been replaced, no pulling or drifting front end, stops straight, normal tire wear, etc etc, but it always happens again and again. My wife has no NASCAR dilusions, she drives normally - not locking up the brakes, she lets off the gas and coasts a bit at corners, etc. I even had ceramic pads put on with the last new rotors, (Ouch$$) cause someone (not the auto-parts salesmen) told me it may help, because they run cooler…Can you Help me - Please?

Thanks,

David Warped L.

#2

Here’s the first thing I’d suggest from the owner of a car that tends to similar problems: make sure that the lugnuts are torqued with the proper force and in the proper pattern. On my car, it needs about 95-100 ft-lbs in a star pattern. It really can make a difference.

#3

mr josh is completely correct and DO NOT trust a shop to use a torque wrench unless you watch them do it. After losing a couple of sets of rotors myself I always re-torque my lugs if I’ve had work done requiring tire removal.

The one other thing to make double sure of is that the mating surfaces between rotor and hub are completely clean and smooth - no rust or any other chunks no matter how small.

#4

I agree on the tightening. It’s even be worth buying a torque wrench and doing it yourself (Sears has them, get the 1/2 inch drive version, $70 or so).

#5

If the lunkheads in the shop use a rattle gun and torque the lug nuts down to about 130 ft/lbs the damage will be down by the time you get home to re-torque them.

It’s imperative to find a shop who understands the importance of proper clamping presure. Some do, a lot don’t.

#6

How are your rear brakes? They may need some attention. There is a small chance that the front brakes are doing too much work. If the rear brakes are working, you may have the problem car that never gets fixed. Warped rotors seem to happen very often these days.

#7

This is a very good point. I’d wager that a large number of cars on the road have no functioning rear brakes at all.

#8

Here’s a scenario. Many times a slight bit of looseness due to wear will develop in a wheel bearing, suspension component, etc.
With new brake rotors this looseness may not be noticeable to you. After putting some miles on the new rotors those new rotors will warp to some degree.

Normally one may not notice a couple of thousandths of warp but when combined with the previously mentioned wear in the suspension component or wheel bearing the looseness is magnified and made to feel worse than it actually is.

The main things I would suggest you examine would be the lower ball joints, tie rods or tie rod ends, and wheel bearings for any looseness. If any slop is present then repair that and the brake problem may disappear. Hope that helps.

#9

Are you buying your rotors from the Dealer’s parts dept? Call them and have them describe the rotors they provide the shop compared to what is available from the aftermarket.

Are these ventilated rotors? It comes to mind that perhaps a design error has occured,the rotor dimensions are not adaquate for the car.

When you start seeing one model with a large number of pulsation complaints you start to think of design error (the car I am thinking of is the first fwd Impalas and the C Pickup line 95-99)

#10

You might want to rethink “the best available,” if that implies OEM. Big, heavy rotors are less liable to warp, but also hurt MPG, which implies a CAFE hit for the manufacturer. If able, buy aftermarket by weight…thicker rotors=more iron. Recently, I bought aftermarket rotors that required ~0.5mm shaved off of the caliper brackets to fit!

Also, breaking a 19mm socket caused me to “hate on” tire stores that WAY over torque…does anyone know if this is simply laziness or some sort of liability thing?

#11

Some damage might be done, but he’d be better off retorqueing right after than driving them improperly torqued. The discs aren’t permanenetly bent by the over-torqueing, they’re warped and held in than condition over months of use. Eliminate the warp, and the problem should be reduced.

#12

I can personally attest to that.

Several years ago when I mounted my winter tires, I inadvertently torqued the lug nuts to 100 ft. lbs. A couple of days later, after having driven only about 30 miles, I realized that the correct torque was actually 72 ft. lbs.

I immediately corrected the situation, and had no problem with rotor warping. However, if I had waited a few more days and had piled on the miles, I don’t think that I would have been so lucky.

#13

You can use a “rattle wrench” if you also use the correct torque stick,going straight from the gun with the socket deseves a lable stronger than lazy.

I have worked with mechanics that say “they know their guns”. so overtightening will not occur,this mind set comes from young and old

#14

Try this next time, instead of turning or replacing the rotors, find an empty road and do a hard 60-5 braking. Don’t lock up the brakes, just hard braking and do not stop completely. One or two of these should do the trick. This cleans off any residue from new pads being “bedded in”.

You refer to pulsing of the pedal. That would not indicate warped rotors, warped rotors will usually cause a shaking of the steering wheel when braking.

#15

does she ride the brakes alot or brake at high speeds hard? sound like your calipers are sticking sometimes maybe try some high performance slotted rotors next orderem off the e or buyem from advanced that should do the trick