Warping rotors

impala
chevrolet

#1

I have a problem with the front rotors on my '01 Impala warping. The pulsing is really bad when decelerating from highway speed. They will last maybe a month after installing before they start to warp again. I purchase my parts at the local NAPA store. Is there something I could be doing wrong during installation or it bad parts (cheap material)?. Could it be an issue with other front end components?. The car has 173,000 miles on it. I need to fix this problem again so any help on this problem would be greatly appreciated.
Thanks


#2

Are you installing OEM specific brake components? Or are you installing the cheaper brake components from NAPA?

Tester


#3

I would measure the runout on the hubs. If that has runout, the rotors have no chance.
Take off the rotors and also make the hubs aren’t rusty.
Make sure the calipers aren’t binding.
Make sure the caliper slides and pins aren’t rusted and seized.


#4

you can find a shop that can machine the rotors while they are on the car. this will match any variations between the rotor and hub, so it will be take longer to redevelop the problem.
what you may be doing wrong? could you be over-tightning the lug nuts? are you missing any binding or dragging caliper components? or could you be over-using your brakes while driving?
try increasing your following distance to the car ahead of you. try starting to slow down sooner before stopping or turning.


#5

Collapsed brake lines can cause the rotors to stay engaged and overheat the rotors too.


#6

I usually buy the less expensive rotors. Would it better to buy the more expensive ones? Is there that much of a difference in quality? I do lubricate the pins. I will check the slides for corrosion.


#7

I haven’t had much bad luck with the “less expensive ones”, sure they don’t last as longer, but not just one month. In addition to what has been said, given the car has high miles, are you sure the pulsation is not from the front end/suspension?


#8

It’s possible that the front end/suspension could be part of the problem, the struts are original. But why would the pulsating go away for awile after the rotors are replaced?


#9

What about using drilled and slotted rotors? Would that help?


#10

heat warps rotors. Perhaps these are cheap rotors that are warping under “normal” braking. Or, the rotors are OK, but the brakes are overheating due to the calipers not fully releasing the pads. If you are sure your calipers are ok and there is no problem with them fully releasing the pads, then you buy better rotors.

I suspect there is a problem with the calipers, or a hydraulic problem (malfunction of an equalizing valve, kinked or collapsed brake line) which is not allowing the pads to release. Drive the car for a few miles with as minimal braking as possible, find a slight uphill grade so you can stop without braking and then check the wheels and brake rotors for heat. Is one or two significantly hotter than the others?


#11

Maybe the problem is a loose wheel bearing or suspension component. Sometimes what will happen is that a new rotor may warp a bit in use and any warpage will be within the limits.
If a situation exists with a loose wheel bearing or suspension component then the slight amount of warpage that you may not normally notice can be magnified and become noticeable once a few thousandths of an inch warp sets in.

Just throwing that out there in addition to the advice you’ve already been given.

Might just add that I like your ID… :slight_smile:


#12

Improper torque on lugnuts and sticking calipers are the 2 most common causes on my list.


#13

Yes. There’s a big difference in quality between OEM specific rotors and cheapo rotors. And this could be what’s causing the short life of the rotors.

You can read how important it is to install the proper rotors here. http://www.aa1car.com/library/2003/bf10312.htm

Tester


#14

I’ve found GM rotors (I noticed you have a Chevy) sometimes aren’t real swift. NAPAs less expensive rotors might be cheap castings. I’ve never had a problem with NAPAs premium rotors, and given that they are probably half the price of the rotors you’d get at the chevy dealer parts counter, I think it would be worth a try. Also, torque those wheel nuts properly!


#15

Are you cleaning them well with brake cleaner before installing them? They’re shipped with a corrosion preventative coating that if not cleaned off well will present as warped rotors.


#16

Now that winter has released its icee grip on us here in Minnesota I can get out to the garage this weekend to work on my brake problems. I have another set of rotors that I have in the garage that I got from my neighbor that appear to be in pretty good shape. I plan on having them turned to clean them up if possible. By looking at aa1car.com that Tester suggested they appear to be of the lightweight replacement type so we will see. If I can have them turned do I need to replace the pads? If I buy new premium rotors do I have to replace the pads? They don’t have that many miles on them. If I have to replace the front calipers do I have to bleed all four wheels or just the front two? I am concerned about the being able to turn the bleeder screws on the rears that have never been touched in twelve years!
Dilligara


#17

@dilligara

Any time you open the brake system, you bleed all 4 corners

Soak the bleeder screws in penetrant now. Let that work in ahead of time
Use a box end wrench or line wrench to crack the bleeders

DO NOT USE AN OPEN END WRENCH TO CRACK THE BLEEDERS. YOU WILL MOST LIKELY ROUND OFF THE BLEEDERS AND MAKE THEM THAT MUCH HARDER TO LOOSEN AND YOU WILL HATE YOURSELF.


#18

I pretty much agree with the above except that if the front calipers are replaced, the rears do not need to be bled, however, I do recommend and I practice this, when ever I work on the brakes, I flush the whole system. You are asking for trouble if you don’t, IMO.

I always crack each bleeder with a 6 point socket before flushing or bleeding.

But in the case of your problem, the first thing I do is find a little used road and then do a couple of hard applications of the brakes form about 60 mph. You do net need to come to a complete stop, if fact it is better to get off the brakes at around 5-10 mph. Two of these rapid 60-10’s should do the job. Do not lock up the brakes, just short of that. Just short of activating ABS also. You want to generate heat.

This cleans the residues off the rotors, especially after new pads have been installed. Its free, easy and works most of the time so why not try it.


#19

It’s common that if you over torque the rotors while they’re still new, you’ll warp the rotors.

It has more to do with the procedure than the quality of the rotors.


#20

If you live in the rust belt it isn’t often possible to open 12 year old bleeders, if you snap off the bleeders our parts stores won’t take your old caliper as a core.
The only success I have had is to take the caliper down to my workbench and heat it. If I am going to that trouble I blow the piston out before I take it off the car and rebuild it myself.
Doesn’t seem to be worth the time anf effort considering how cheap rebuilt calipers are.