Constantly warping rotors


#1

Warping rotors every 3-4 months, can’t find why they get so hot. Dealer, tire shop, both have checked. I don’t brake hard, no emergency stops either. 03Toyota Tacoma, 2WD,vented rotors, 3.4 engine. Checked for hanging/stuck pads, all ok. Thinking of buying expensive slotted drilled rotors…worth it? Any brand suggestion? Thanks


#2

There’s a possibility the problem is not the rotors at all and this could be why. A loose wheel bearing, tie rod, tie rod end, ball joint, etc. can cause a brake shudder and this could be especially true if the part in question is slightly worn instead of flat worn out.

After a few miles a rotor may warp a couple of thousandths of an inch. Depending on the vehicle this may not even be noticeable.
However, if one of the items I mentioned is questionable this few thousandths of an inch may be magnified and made to feel much worse than what it is. This is why a new or machined rotor may not exhibit the symptoms at first; it has to develop that few thousandths of an inch warp from heat and combined with a loose tie rod or whatever may cause an annoying shudder.

You did not state the vehicle mileage but assuming it’s average I would look closely at the tie rods or tie rod ends for any looseness. Hope that helps.


#3

Thank you for the reply…mileage is close to 90,000. The tire shop has actually had to machine down 2 sets of new rotors after about 4000 miles on each new set, finding that they were warped. Would the front end tie issues cause the heat and therefore the warping?


#4

No. All rotors are going to heat up and warp a little; usually a couple of thousandths of an inch. Around .002 of an inch is generally considered acceptable and often is not noticeable.

I think they’re missing something here. No way should you be going through new rotors and machining that often.
If they’re going to diagnose the rotors as warped then they should back this up with a test. This is often done with a dial indicator on a magnetic base and rotor parallelism can be checked with a rotor caliper or micrometer. Really, there is no guess work on this at all.

If you want to determine if you have a tie rod or tie rod end problem (this is the most common fault) simply jack the truck up one front wheel at a time. Grasp the tire at the 3 and the 9 o’clock position and gently try to wiggle the wheel assembly in and out. You should not feel any movement in the wheel. If you do, odds are the tie rod or tie rod end is worn and loose. Environment and driving habits can play a big part in which one is loose. A lot of city driving may wear out the tie rod end. Around here in NW OK the roads are generally straight until oblivion and it seems the tie rods wear before the tie rod ends. Hope that helps.


#5

I have not actually been there to view the machining. But I will next time. Trustworthy tire/front end shop doing the job. Also been thru local Toyota dealership to make sure no system problem, for as you can imagine, this frequent and now laughable predictable problem is driving me broke and crazy. I installed this pair of rotors myself, and within 3k, shimmy shimmy on braking…and son of a gun…same ol’ warping. They cut 'em a bit, and all ok after that till this week…4k later. No reason. Not riding brake, tests do not turn up caliper or pad sticking, but we all know its only heat that can warp them. Alas, what we are all missing, none of us know.


#6

What kind of rotors are you using?

I had major warping problems with some inexpensive NAPA rotors (they sold three grades, I guess I should have sprung for the better ones) so I replaced the problem rotors a few years ago with four new Made-in-Mexico Brembo rotors. No problems at all with these.

Retrofit drilled rotors on vehicles that did not come with drilled rotors are rarely a good idea. They work OK on motorcycles, though the buzz is annoying, but they tend to crack when used on cars. Slotted rotors are OK I guess, but people seem to try them once and then go back to conventional.


#7

Here’s an article by a former Shelby GT engineer about brake pads and rotors: http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
When coming to a stop, creep up on the stop point, with your foot off the brake the last few feet. This will allow the brakes to cool a little.


#8

Thanks for the reply. I had wondered about the quality. I’ve been buying similar to NAPA grade basic I think. They run usually less than $60. Were the Brembo’s you wrote about their basic oem replacement rotor? Your point on the drilled/slotted rotors does make sense. I would rather figure out why they warp so often in the first place. Where the heck is all that heat coming from that would warp it with such frequency. Even a basic rotor shouldn’t have that much of a reaction unless I’m using a heavy foot.


#9

Thank you for the reply…will read the article this evening. I do appreciate your help. This has been the only issue with the Tacoma since I purchased it used…I am wondering if that’s why it was traded in. Even the dealership’s brake guy was baffled, as are my mechanics. I am wondering if, as pointed out by the response just above yours, whether or not I’ve been buying cruddy quality. Will read the article, and no matter what, I’ve got to replace the existing warped rotors…but this time with a “best” quality rotor.


#10

One other cause - uneven/too high torque used when installing wheels. Given your cars troubles, you need to insist on only the use of a torque wrench the next time they put the wheels on.


#11

Lug nut torque is important, and may be your problem. My experience is that most mechanics over torque lug nuts because they are afraid that they’ll (the lug nuts) fall off and they’ll (the mechanic) be sued.

I always put a torque wrench in my trunk when I know someone else will be removing and installing wheels. I always check lug nut torque before I drive away from the service facility. My lug nuts are supposed to be torqued to 80 ft lbs. They’re usually at 110-120 ft lbs after a “professional” mechanic has installed them.

I have a 1992 Accord whose rotors have 220,000 miles on them. They were turned at 90,000 miles to eliminate vibration.

My wife’s 1998 Accord has 197,000 miles on the original rotors. Never been turned, never had a vibration.


#12

Thank you and also Tex for both of your responses. Yes, I found out the hard way on one of my recent replacements of a new pair of rotors. Brand new, out of the box, I drive up the street, and unbelievably, the front end and wheel shimmy even worse…and like you say, they used the air gun to tighten up and warped them with not even a mile on 'em! I am now well aware of the torque wrench tighten on this pickup.


#13

At the risk of pirating this thread, I would like to interject a warning that when most tire shops say that they tighten your lug nuts with a torque wrench, what they MEAN is that they tighten the lug nuts with an impact wrench and then pick up the torque wrench and check to make sure that all lug nuts are tight. The lug nuts on a single wheel may range from 85 to 125 ft-lbs, but all they care is that they are all at least 80. That is why I carry my rims to the tire store to get them mounted and balanced and then I carry them back home and put them on my cars. No one but me ever puts wheels on my cars.


#14

I’m always the odd man out here but I’m still not convinced the problem is brake rotor related nor is it due to overtightening of the lugs.

If these rotors are allegedly warped from the get-go, or a few minutes afterwards, then why is this not verified with a dial indicator by the shop? It’s grade school easy to do. Just pointing this out, although I still don’t think the problem is warped rotors.

How hard would it be to simply place a dial indicator on them? What happens if the indicator says “within specs”?
Does this shop, or shops, even HAVE a dial indicator to check this with? If not…they’re guessing and praying.


#15

If you are going to consider slotted rotors, EBC would be a good choice.

http://replacement.car-stuff.com/parts/carstuff/wizard.jsp?year=2003&make=TO&model=TAC-2WDV6-001&category=N&part=Brake%20Disc&returnurl=null&dp=true&showdc=true#top

Don’t do the drilled and slotted, they are prone to cracking under street use.

Every 4000 miles indicates to me that you don’t have warped rotors, just a build up of resins on the rotors. The fact that you don’t brake hard occasionally is why the resin isn’t burning off. This time, go to a little used road and do a couple of hard stops, not lockup, but hard 50-10 stops, don’t stop completely or it will cause localized heating of the rotor and that will warp it. Two of these followed by a few minutes of steady speed driving to cool then brakes back down should do the trick.


#16

I had this problem on my 98 Tahoe. I solved it by buying NAPA premium rotors on the advice of a mechanic. It solved the problem. They are not slotted, just superior metal.