I'm having an issue with the rotors warping on my 07 XKR (non Alcon) after about 1,000 miles. The dealer will replace them, steering is smooth, then after about 1,000 miles, the steering wheel will shimmy. They are measuring run out and they are warping. Just standard street driving, nothing aggressive. Anyone else had problems with this? They do not see any issues with the suspension.

 

That's crazy, shouldn't happen like that. Do you wash your car after driving ever?

 

No, usually it has been sitting in the garage when I wash it. They also checked the calipers and they do not appear to be sticking.

 

Is it one rotor or both rotors. Usually the cause is either rapid cooling or uneven rotor pressure caused by the calipers. Also if the rotors were to thin from wear but if they are new then that won't be the problem. I would start looking hard at the calipers. Also consider the brake hoses as if they are worn they act just like a check valve and don't let the calipers bleed off. good luck

 

The common consensus from most brake specialists is that there is no such thing as a warped rotor unless you track a car or maybe fail to torque your lugs properly.... More than likely you have not bedded the pads per manufacturer instructions...
Past experience has shown me that you can still bed the pads, even after they have bedded improperly, by going out and doing the bedding procedures over again plus a couple...

You might consider giving that a try first....

 

My car had 4 out of round rotors after 4800 miles.

 

Not saying warpage isn't possible, but for you to loose 4 rotors says you had something else going on, not bad rotors.
There are plenty of technical write ups discussing the myth behind warpage from far more educated folks than myself, but the majority of the conversations center around improper bedding of the pads...
I have done so myself.... only to have to go out and re-bed them to get rid of the braking shudder.

Stoptech
Wilwood (Brake Pads - What is "uneven pad deposition,")
Power Stop (What causes rotor warping?)
Moss Motors
Tire Rack

BOL
Vince

 

Good suggestion and I didn't consider it. Here is the process that I usually use and it works pretty good.

Instructions for bedding in your brakes

 

The issue is with just the fronts. The dealer followed Jaguar's bedding procedures. The interesting this is that it is just steering wheel shimmy, no pulsation in the pedal.

 

OK good other info here. Do we assume the dealer checked rotor run out both on and off of the car. Also has all of the suspension and steering components been checked. Then were the wheels checked for any damage or being bent. You would have to remove the tires to do a check and you can also have the tires balanced on the car as another option. Rack and pinion as well as steering column should also be looked at. Find out what the dealer has done .

 

I tracked my car with stock brakes for months and never had a single rotor warp, and toasted the brakes. I went through 4 sets of pads had didn't have the slightest vibration. Even the last track day which left the rotors scored due to the pads overheating were just fine after a resurfacing.

If you're having vibrations under braking its an issue with uneven pad material on the rotors. This is most likely due to not bedding the pads correctly. This is very important as new pads needs to leave pad material on the rotor surface to actually be effective. Its even more important if you changed pad materials without resurfacing as the two will leave a differnt coating on the rotors. Any of this can cause the pad to go through different friction properties and cause a vibration during braking. Simply using an emery cloth to remove old or uneven material will help. If you have driven a good distance and the pads never bedded they could be glazed from over heating, then you need new pads once again.

Always bed your pads correctly it fixes nearly every braking complaint, from squealing, shudder "warping" glazing, long stopping distances, etc... Everything but dust Think about warping for a moment if the rotor was actually warped the car would shake and shudder even when you weren't on the brakes.

 

Which tells me the left and right side brakes are going through different fiction properties causing a grab on one side. This causes the wheels to feel like it's shaking, when its actually the pad grabbing and then slipping under the same brake pressure. This is normally caused by brakes that aren't bedded or switching compounds and not replacing/resurfacing the rotors.

Brakes need a clean surface to lay down a film of pad material on the rotor when they are first used. This is what actually stops the car. Different brakes have different bedding procedures, but never pull out of a brake shop and just normally drive the car or its game over. Just one hard stop at a traffic light and your embedded your rotor with hot pad material that it soaks in and all of a sudden you have a shutter.

 

Interestingly, I had a brake shudder in my brand new XJL under moderately hard braking from freeway speeds. At the first regular service the dealer changed the rotors and the pads which eliminated the issue. Now, about 6000 miles later the shudder is back. My next scheduled service is due in about a month so, we'll see how the dealer handles it.

 

Cars that get driven very little can have issues with brake shudder. I was told that the rust adheres to the rotor from lack of use. That may very well be the reason I had a shaking steering wheel and undercarriage shudder when applying my brakes to a car with 4,800 miles. I had all 4 replaced to the OEM rotors. So far after 2200 miles all is well. I'll keep my fingers crossed.

 

thats another reason there I forgot about, and if you have the E brake on its even worse. You are absolutely correct in that the rust collects on the rotor and will cause an uneven friction surface. Depending on the rust you should be able to have them resurfaced with minimum removal of material.

thank you for reminding me to drive my car more

 

Mine is driven daily so rust should not be an issue.

 

Absolutely correct. Lots of perfectly good rotors get tossed or have valuable metal removed by 'turning' them on a lathe.

In almost all cases, the cause of the pulsing is deposits of brake pad material on the rotor surface. This can easliy be removed with a rotary abrasive pad. 3M makes a kit.

 

NOPE, DEPENDS ON THE AREA WARPED. AND HOW TRUE THE HUB AND ROTOR TO HUB SURFACE. THERE ARE SEVERAL ISSUES HERE. AND IM NOT PICKING ON YOU MAXIMA YOU HAVE GREAT POINTS. THESE ARE GENERAL ISSUES I SEE WORKING ON THESE ALL THE TIME

1) ALCANS ARE A FIXED CALIPER AND YOU WILL FEEL MORE BRAKE FEEL, PULSATIONS ETC THAN YOU EVER WOULD A FLOATING CALIPER.

2) REALLY CHECK RUN OUT? AND HOW WITH THE SCALLOPED ROTR OR DO YOU HAVE FLAT SURFACE. YOU CAN BARELY RUN A DIAL INDICATOR ON THE SURFACE EXCEPT THE VERY EDGE WHERE YOU WONT HIT A SCALLOP.

3) JAGUAR SPECS .008" OR LESS AS ACCEPTABLE
TOTAL BS. .003" AND HIGHER I FEEL.

4) A HUB SHOULD HAVE 0.000 RUNOUT PERIOD. IF ANY ITS BAD

5) AND RUNOUT IS MAGNIFYED THE FURTHER OUT YOU GO ON A ROTOR. SO A INNER READING CLOSE TO THE HUB MIGHT BE .002" AND FINE. NOW GO OUT TO THE EDGE AND ITS MULTIPLIES EVEN MORE AND MIGHT BE
.008-.012"

6)ALIGNMENT AND WORN BAD CONTROL ARM BUSHINGS CAN ALSO CAUSE THIS AS THE FORCES IMPARTED TO THE SUSPENSION ARE VERY DIFFERANT WHEN BRAKING AND VERY LITTLE FEEL /FEEDBACK WHEN DRIVING CAN BE MUCH MORE MAGNIFYED UNDER BRAKING FORCES.

AND IS IT A BRAKE ROTOR/PAD SHIMMY OR TOLERANCES IN SUSPENSION. OR STEERING RACK PINION BACKLASH CLEARANCE OR TIRES. 2011 XFR I DID TODAY WAS TIRES FOR SHIMMY OR I CALL IT A KIBBLE. WETHER BRAKING OR NOT BUT WAS WORSE BRAKING. AND LESS AIR PRESSURE MADE IT WORSE TO(ROAD MORE ON THE FEATHER EDGED CUPPED PORTION. NEW TIRES AND TOTALLY GONE.
HER DESCRIPTION( AND SHE IS A CAR NUT) WAS VIBRATION. BUT AFTER DRIVING I CALLED HER AND AGREED IT WAS NOT A VIBRATION BUT SHIMMY OR KIBBLE IN THE STEERING WHEEL. TIGHTENED PRELOAD ON RACK SLIGHTLY, ALIGNED CAR AND REPLACED ALL 4 TIRES(THEY WHERE CLOSE TO WEAR BARS ANYWAY SO NOT A WASTE) AND WHEN DONE IS NICE AND SMOOTH.
HOPE I SHED A LITTLE MORE LIGHT IN OTHER NOT MENTIONED AREAS THAN THE ALREADY GREAT POINTS BROUGHT UP.

CRAP AND A LONG WINDED POST IN CAPS IM GOING HOME

DAMN AND I THINK OF MORE... NEED TO CHECK PARALELLISM THCKER/THINNER IN SPOTS. THIS IS MOST OFEN CAUSE BY YES SLIGHT RUST THE HAPPENS OVER NIGHT OR DAY OR 2 NOT DRIVEN IN HUMIDITY OR RAIN EVEN FASTER. WHEVER THE PADS ARE ON THE ROTORS THE Y DONT RUST, THE EXPOSED AREAS DO. THEN WHEN YOU BRAKE AND CLEAN THE ROTORS THE RUSE IS GONE, PROBLEM IS THE RUSTED AREAS ARE SLIGHTLY THINNER NOW THAN WHERE THE PADS SAT. YOULL FEEL THIS TOO.
OK NOW IM GOING HOME

 

Good point Brutal........That's exactly it. It's where the pads sit when a car is not driven for some time that the rust builds and even if the rust is removed, the rotor will not be true due to that one spot.

 

Brake rotors warping being a myth ... is in itself an internet myth.

Who says so?

1) A RAYBESTOS brake engineer who teaches other engineers the finer points of rotor metallurgy. He dealt with the topic in a brake rotor engineering course.

2) A brake system engineer who has worked for both ATE and FORD in that order.

Being people who are directly involved in the manufacture of brake rotors, their views are more reliable than internet myths no matter how often they are repeated.

As for the opening post, perhaps Jaguar has a batch of bad rotors in the supply chain. One of the factors dealt with by the Raybestos engineer in the course was the rate of cooling after casting. Improper cooling can lead to a latent warping problem that shows up after a few heating and cooling cycles.