Warped brake Rotors

andys120 · March 2002

I used to own a '91 Taurus SHO. Among the many maintainence issues affecting that car was a repeated ocurrance of brake rotors warping. I was told by a dealer principal with whom I was friendly that this was caused by over tightening wheel nuts when mounting tires.
I didn't believe it because I'd never had the problem recur so frequently with any other car. Most cars I've owned never had the problem but a buddy has had it w. 2 different Tauri.
Oddly it's never occurred on my other Ford product ('86 Mustang 5.0L).
Was he making excuses for Ford or just passing on an old wive's tale, or is there something to it???

armtdm · March 2002

New Buick has had a chatter since new, finally took it in at 19,000 miles. They repalced all foru rotors. Seems to have solved the problem However, lug nut came off about a week later but the rest of them seem okay,.

8u6hfd · March 2002

Sounds like he's making excuses.

pjksr · March 2002

For about $55, you can buy a decent click-type torque wrench at Home Depot.

Lug nut torque should always be checked a couple hundred miles after tire changes--or whenever you let anyone work on your vehicle ;-)

jgmilberg · March 2002

On some of the cars that only have 4 lugs and even some with 5 lugs on them, an uneven amount of torque WILL cause them to warp. Older cars have studs on the rotors and the wheel bolts to that only making them less likely to warp, on newer cars and most new trucks, the rotor slips on the studs and hub and the wheel bolts down over that. Essentially making a rotor sandwich, and like a sandwich if you put to much pressure in one spot it will flatten it out making it warp. This is really over simplifying how it works, but it gives you a general idea.

Some other more common ones are using 2 feet to drive, the left one usually ends up resting on the brake pedal causing them to drag. Another one is bad caliper hardware or a stuck caliper overheating the rotor causing it to warp.

One other common misconception I have discovered is that if you turn a warped rotor to make it square again it only warps again because you have removed more material from one part than the others causing a thinner spot, and that spot is more likely to overheat than the thicker spot, once again warping the rotor. In general if I have a warped rotor I replace it and go over every part of the brake system to make sure it's fixed right. After that all that's left is over torquing.

I am a GM fan through and through, I have seen this happen on GM cars too, the Cavalier/Sunfire come to mind right away. Watch those tire guys, make sure they use torque sticks and a click wrench to tighten your rims.

zr2rando · March 2002

If you get home and wash the car and hit that wheel/rotor with the hose while its hot....
ther ya go!
see y'all
Rando

zueslewis · March 2002

newer ('89 up) T-birds and Cougars, Sables, Mustangs and FWD Lincoln products, Ford had major issues with brake rotor warpage. It happens now with many cars due to two problems: the OEM rotors are too thin to dissipate heat, and warp as they're being used; asbestos is no longer in brake pads - asbestos was very good at stopping cars and absorbing heat, where heat wasn't transferred to the rotors. The new pad materials, mandated by the EPA, stops cars OK, but retains much more heat, damaging rotors sooner. It ain't that your lug nuts are too tight!

The only cure is to replace the front rotors with Taurus Police rotors from Bendix or another good brake component company, or if you don't mind shelling the dollars, contact Baer Racing - they make a 4-wheel replacement kit with bigger, more gnarly rotors that will lower your braking distances considerably.

Jim

swschrad · March 2002

my middle fingertip is healing rather nicely, but I gotta tell you, fastest way to get a dime-sized blister is to drive about five miles, normally, no hammer-em stops, notice some discoloration on the rotor, and touch it to see if this is baked-on crud from the pads coming apart.

those brakes are converting, in the case of my exploder, 3200 pounds * 40 mph of energy into waste heat in several hundred feet at every stop light. that's a lot of calories. the rotor or drum is the only place to sink that heat away. plenty enough heat to warp a big chunk of solid metal, which is why rotors are made like the Fan Impellers From Hell, and why there are big holes in wheels.

tire monkeys with air wrenches are public enemy number 1... it's much better if they start on "first click" and star-pattern across the bolts several times to get things tensioned right. that also minimizes the chances of "cocking" the wheel at the edge of the threading on one bolt because the opposite bolt(s) were taken tight right away... that makes the wheel a lever that with the heat is sure to warp a rotor in a relatively short distance.

and once warped, you are never going to get that rotor straight again.

bolivar · March 2002

..that a problem is the pins lose their lubrication, or when brakes are rebuilt the pins are not lubed.

And the calipers slide on these pens. With no lube the calipers, with the pads, will drag and cause more heat in the rotor, causing warping.

In general, I think the rotors in the last few years are being made cheep (low quality steel or thin rotor) because you are hearing a lot about warped rotors on all kinds of cars.

Not long ago I drove a 1998 Caddy Seville with only 4,000 miles just coming off a 3 year lease (yes, you read this right, just a little more than a 1,000 miles a year driven!) and it had badly warped rotors. Sevilles are known for this problem. But in 4,000 miles?????? It did come from Michigan, I wonder if the combination of salt and very low usage caused the calipers to freeze up and cause warping even faster.

I also drove a 97 Seville at about 27,000 off a 3 year lease and it also had warped rotors.

Like I said, it's rather common now on a lot of cars. And this is something you never heard of happening until 60,000 or more miles 15 years or more ago

andys120 · March 2002

swschrad · March 2002

if they could make the OEM rotors even thinner, the pads would be riding on each other.

you have a point on the thread lugs being used dry and dirty, that's another reason why 5-minute-Fred scares me at tire places. the flip side is that I have seen recommendations that the wheel lugs NEVER be lubricated, because excess grease will supposedly also cushion the nut on the lug, and it will shake loose.

hanging calipers will also definitely beat the rotors up, but there should be some sense of the car "pulling" or extra noise most of the time. I had one hang, barely, on the right front recently, and a car wash and the old self-adjusting drum trick of backing up at about 10-15 mph and doing a firm stop got whatever was sticking on the pin free.

andys120 · March 2002

as on the regular Taurus?

If they did it's a built in design flaw that any rookie engineer or amateur mechanic could tell you was WRONG.

zueslewis · March 2002

are different, because the SHO has larger diameter rotors and uses rear discs instead of drums like on the regular Taurus. The SHO rotors are made of the same thickness of material, though, and are just as prone, if not more so, to warpage.

andys120 · March 2002

bburton1 · March 2002

Older honda cars had awful problems caused by yahoos using air impact wrenches to tighten lug nuts. Had an 80 accord and it got to the point I would take my torque wrench and make the tire change guys use it instead of torque sticks.

Also older Honda disk replacement is a bear because they are pressed into the front wheel bearing assembly. Supposedly 98 and up rotors are much easier to replace.

So watch out when anyone changes tires on your vehicle. You could get bent rotors out of the deal.

vidtech · March 2002

Not sure if this was posted before.I have found the chinese made rotors are very prone to warpage.it just shows you can't beat good American steel.I never had problems with replacement rotors or drums until the stores started selling the cheap chinese parts.I cannot even find a store that stocks rotors made in USA anymore.

jgmilberg · March 2002

It really sounds goofy, but vidtech is right. For me when I use the China made rotors they wear out faster, or warp easier than American/Canadian ones. I know that Pep Boys carries Raybestos brand rotors made in the USA, and that's the reason they cost more, about 20% more in fact when compared to imported (Chinese) rotors. I also have had very good luck with Canadian rotors/drums, I can get them from my local parts store, Murray's Discount Auto Parts, they actually used to carry Chinese and Mexican rotors and drums, but had a lot of them come back warped or not lasting through the warranty period of 2 years. At least they noticed the problem and switched vendors and are finally getting good parts for those who work on their own cars.

fdchief · April 2002

Can anyone tell me anything about warping rotors on my 2001 Chevrolet Impala. Purchased new Feb. 2001 - one year and 35,000 miles later only problem has been taking back to shop 5 times for smimmy (rotors each time). They are giving me a line it's because of the 4 miles a day I travel on dirt roads to get to and from home! They have replaced the rotors, trued the rotors, replaced pads and turned rotors. In one thousand miles this baby is mine and not the dealers problem, any suggestion. P.S. For the record, I told them when purchasing the car I travel dirt roads and put a lot of miles on my vehicle working, thus needed one which is comfortable and able to keep up! Help, Help, Help it's doing it again!

gsleve · April 2002

did not torque the lug nuts to factory specs thereby heat generated by the brakes causes warpage of the rotor. Situation may not be rectifiable due the initial damage may have to opt for new rotors and pads.

Just a thought

zueslewis · April 2002

I can't tell you how many Impalas, Malibus, Grand Ams. etc (mid-size GM products) I seen that have warped brake rotors. It's the quality of the rotors (thickness and material) combined with heat.

anon70 · April 2002

during my last brake job (at midas), i had my rotors machined. after three thousand miles, i start to hear a low, deep noise of metal grinding when i am at slow speed and come to a complete stop. this continues on and off.

at that time i was taking automotive classes. my prof said the rotors looked too thin. i got new ones @ $18 each. (Midas is SUCH A RIPOFF. they charged me $50 per rotor to machine them while on the car!)

10k miles later (my class has ended), the noise has returned. is it the rotors?! how can i tell if it's warped? (my prof didnt say anything about the old ones being warped.)

swschrad · April 2002

it doesn't take many thousandths of an inch to make a big wobble under braking (or to drag once a revolution on the pads), and if you have a runout indicator (dial point micrometer), pull the wheel and fix it to a stand at the side of the rotor, needle in contact with an area near the outside of the contact footprint. a runout indicator shows plus and minus from 0... if your dial indicator doesn't, set it so you are maybe showing .010 inch, aka the micrometer is being compressed where the detector needle is hitting the rotor.

slowly spin the rotor around. on any rotor, there is bound to be some minor movement of the dial pointer... but it should be under a specified range for the vehicle. for sniffs and grins, let's say .005 maximum runout is the spec on your car. if the needle is swinging from .017 to .002 you are finding a warp out of spec.

the tool is probably in the $100 range give or take, but any serious mechanic who does brakes will be equipped, because that's how you qualify a warped rotor (needing to make a payment does NOT constitute a test for valid anything.) so any mechanic who works brakes should be able to do this for maybe 30 minutes worth of labor charges and a couple bucks worth of the usual shop rags fee.

alcan · April 2002

Rotor warpage will show up as a brake pedal pulsation, more pronounced at higher speeds under heavy braking. If semi-metallic pads were installed, the grinding noise is probably due to the metal content of the pads. Most manufacturers' specs for rotors are .003" maximum for runout or warpage, .0005" for parallelism or thickness variation.

bburton1 · April 2002

If they are really warped, the whole front end will shimmy when you hit the brakes. Before I figured out what the tire change jockeys were doing with their air driven impact wrenches, I had this happen several times on a 80 accord. Helped to just retorque the lug nuts properly. Still shook a bit but no longer a control problem when really standing on the brakes.

When I have tires replaced now-I take my own over priced torque wrench and watch the tech use it to tighten the lug nuts.

zueslewis · April 2002

rotor warpage usually doesn't cause any noise - the grinding noise is either your brake pads or gunk between the pads and rotors. $50 to cut them on the car - that's ridiculous - I'd get a price for cutting rotors from another shop, then return to Midas with the lower estimate and ask for the difference in cash or in-store credit. If the won't do that, make a picket sign!

gosteelers · April 2002

From the time I had 6600 miles to present(71000)
I have had a major vibration from my front
brakes.I have had my rotors cut (3) times.
Has there been any bulletins about this
problem and/or solutions?

zueslewis · April 2002

Galant and Diamante for that reason. The only way to fix it is to use aftermarket brake rotors, like Bendix, instead of Mitsubishi parts.

davidfrancis · April 2002

on almost any car these days:

Accelerate to a good highway cruising speed - say 60-65 mph - brake hard to a complete standstill and hold your foot on the brake pedal for a minute.

The hard stop puts a huge amount of heat into the rotor (that's what it is there for), but holding your foot on the pedal keeps the hot brake pads in contact with the rotor, preventing that part of the rotor from cooling down as fast as the rest, which is exposed to the air. The temperature differential across the rotor then causes warping.

Most rotors are quite thin these days, for cost and weight/CAFE reasons, so they can't resist warping like the older thicker ones.

Warping is felt as a pulsation through the pedal when braking. In severe cases the whole front end may shake, which can be felt through the steering wheel.

Best way to try and avoid it is to brake hard only when really necessary, and to release the brakes as soon as possible after a stop.

Dust and dirt will generally cause scoring of the rotor rather than warping.

aace · April 2002

When I brake at 65mph, I don't feel any brake pedal pulsation. But my steering wheel sometime shake like an earthquake. Is this a symptom of rotor warping or something else? and what you mean by "whole front end may shake?"

gqlefty · April 2002

With new pads and rotors on the front of my 1999 Muatang car should the rotors turn freely when you turn the lug studs with your hand ??? Seems to be a lot of drag from the pads, is that normal ????? I still notice vibration when slowing down quickly on a freeway exit ramp. I doesnt do it with normal brake pressure but neither did my old rotors and pads. I spend 300.00 bucks and still have the vibration in the steering wheel on quick slow downs!!! I'm taking it back to him Monday. HELP!!! Could tires affect the problem any ?? Thanks

Mr_Shiftright · April 2002

Yes, it is normal for the pads to drag.

Your brake shop can do a simple run-out measurement on your rotors to tell if they are causing the vibration. If they don't do the run out test they are just guessing and so are you.

gqlefty · April 2002

Thanks for your reply !!!! So they need to do a run out test even though the rotors are brand new ???? They replaced the pads and rotors yesterday saying they could not turn the old rotors, at least I think they replaced the old rotors !!!! What does a run out test show, so I won't completely be in the dark!!! Thanks again !!!

vidtech · April 2002

before i put an existing rotor back into service i use a screwdriver and go between the cooling fins and knock out all the rust.i never had a warped oncei started doing this once a year.as for pad drag,if the calipers and hardware are replaced at every brake job there will be a SLIGHT drag if any.if it requires a lot of effort to move the rotor,that's too much in my book.

mullins87 · April 2002

Some time ago I replaced the rotors on a car I used to have. The car shook worse after the new rotors and pads than before. I did a run-out test on them, one of the rotors was .019 out!! When I inspected more closely, there was a piece of metal wedged in the cooling viens exactly where the high spot was. Parts store exchanged it no questions, but I still was out a couple of extra hours of labor to swap them out.

bolivar · April 2002

This uses a dial micrometer. A meter with a little 'probe' sticking out. The base of the meter is clamped or magnetically stuck to the frame or suspension nearby the brake rotor.

The probe is placed aganist the milled face of the rotor, the area where the pads push to impart braking action.

The meter is zeroed. The rotor is slowly turned by hand while watching the micrometer dial. The amount of change registered on the dial as the rotor turns is the 'run out'. This should be done for several radius of the rotor and inside and outside surface.

I don't know what amount of runout is allowed while still being within specifications. The brake people should know. The runout is measured in thousands of an inch.

Basically, if there is much 'runout', the variance can be felt in the steering wheel while braking. It usually will not be felt though the brake pedal.

alcan · April 2002

General specs are maximum .003" runout, .0005" parallelism or thickness variation. Clean and lube caliper guide pins and bushings with silicone grease (NOT petroleum based lubes). Same for caliper and pad support surfaces. Calipers must be free enough to move in and out by hand after installation, prior to pumping the piston out. Remove all traces of corrosion from the rotor mounting flange of the hub with a die grinder and 3M pad or equivalent. Same for rotor inner and outer mating surfaces if rotors are being re-used. Torque wheel nuts to spec. If pedal pulsation is still evident, suspect rear rotor warpage or rear brake drum out of round. This can be verified by using the parking brake to slow the vehicle from 30 mph. If foot pedal type, hold the release lever out to prevent the parking brake from locking on. Also, don't overlook a loose wheel bearing or runout in the flange of the hub which the rotor mounts onto.

gqlefty · April 2002

Took my Mustang back, they put on another pair of NEW front rotors..... problem solved !!!! No steering wheel vibration, just like new !!! I stood and watched this time !!!! Really dont believe they ever put new rotors on to begin with !!!! Thanks !!!!! {they never mentioned a run out test}

bonjoe1 · May 2002

Car is making a funny noise on passenger side when stopping. Sounds like a clicking noise. Took it to the dealer and they said the brakes are over 50%, and the rotors are out of round. They said to just leave it alone for a while..until the brakes go down more. Took it today to a different mechanic, but when we test drove the car, it didn't make the noise, so he didn't know what I was talking about. He had inspected the car last month and said the brakes are good...and to just let it go for now, unless the noise gets unbearable. Now, I am thinking of just taking it to a diagnostic center to see if they can pinpoint what exactly is wrong with the car. We did get new front tires recently. We also got all four tires balanced. Any opinions or suggestions...thanks.

snowman · May 2002

Did they find anything with your car? Let us know if they find the problem.

mullins87 · May 2002

Is there any possibility the rotor could be cracked? If it is a small one, the crack could be almost invisible to the naked eye. When the rotor is cold, the crack is "closed" making no noise. When it gets hot enough, it "opens" up and makes the sound. I coworker of mine had this happen on a 1 ton van. He said it would make a clicking noise when he used the brakes.

Just a suggestion in case you haven't considered it.

snowman · May 2002

It makes perfect sense. I think I have the same problem and naturally it comes only if the wheather is hot. I did not hear anything during winter time, possibly my alloys allow them get cooled quickly.

Alcan, after an intense research in the internet, I have decided to go with Raybestos SuperStop pads and new rotors since Motorcraft is asking $130 per piece for rotors (I did not even asked them the pad's price).
My 2000 Taurus has ABS. Any precaution I should take for ABS system or this is pretty much the same process.
Thanks everyone for their inputs.

bonjoe1 · May 2002

The brakes were clicking so loudly today, and the car was vibrating when coming to a stop that I decided to just replace the brakes and rotors because I can't wait any longer. The noise is driving me crazy! I figure, I will have to replace them in a few months, so what's the difference if I do it now or later. At least, I won't hear that noise any more. I told the mechanic to use bendix rotors and not to use Ford's. I will let you know what happens after I get the car back. Hopefully, replacing the brakes and rotors will solve the problem! If it doesn't...then I'll be back on square one again... and a little poorer!

)

alcan · May 2002

Good choice in parts. I'd recommend you open the bleeder screws in the calipers before pushing the pistons back in, to reduce the possibility of any sediment in the calipers from finding it's way back up into the ABS pressure modulator solenoids. After replacement, flush the system until clean brake fluid comes out of each bleeder. This gets rid of the moisture which slowly builds up in all brake hydraulic systems. And use Ford Heavy Duty brake fluid.

bonjoe1 · May 2002

Got new bendix rotors and brake pads and the car is not making the the clicking noise any more, and doesn't vibrate when I stop. That was the problem...
One question..I have noticed with this and other cars, that when the car is cold, and I start driving and stop at a red light..if I lift my foot a little off of the break it makes this really loud noise...but if I drive for a while and do the same thing, it doesn't make that noise any more. Anybody know what causes that? I noticed it in other cars, too.

swschrad · May 2002

disk brakes are more efficient, and have a larger contact area, so you grind off more rust with those first few stops. if you pull into the garage after a rainy drive on Friday, and don't take the car out until Sunday afternoon, it's really going to grab and groan... quite a little coating of red on the braking surface by that time.

snowman · May 2002

Where did you get them installed, at the dealer or some other place? How much was the installation? I am debating whether I do my own installtion or not. I don't have some tools that I need. Thank for you inputs.

bonjoe1 · May 2002

I can't believe this...the brakes don't make the clicking noise anymore...and the car doesn't vibrate...but now there is a sqeaking noise when I apply the brakes..sounds like birds singing! Took it back to the mechanic...he tried cleaning the rotors and pads...but still the noise! Help....what next! Maybe the pads just have to wear in...I got the bendix pads because they were better than the Fords...hope I did the right thing. any suggestions...thanks.

swschrad · May 2002

common squeak issue is that the tech didn't put a silicone lube gel on the back of the pad, I am told. the locally-owned parts chains, when such a thing existed, always made a major point of their including the lube blister-pack in THEIR pad sets, as opposed to maybe Slimey Sam's Alleyway Sales.

kinley · May 2002

alcan · May 2002

At the dimension cast or stamped into the hub. Post the vehicle information (make, model, year, engine, rear disc or drum) and I'll have the spec for you tomorrow.

kinley · May 2002

1966 Ford Mustang GT Coupe
Factory discs in front
Drums in back
Engine = 289 4 bbl 225hp Challenger V8
Transmission = C4 automatic

Warped brake Rotors

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