Hey all,
I'm new to the forum and am happy to be in the good company of S Type aficionados. I have an R series car that is giving me a bit of a head ache with the front brakes. They seem to be warping or at least getting "hot spots" on the rotors after about 1,000 miles (it shakes the steering wheel heavily under smooth braking).

I have changed the rotors and pads twice now (brake performance parts) and am beginning to experience the same trouble again on these new rotors after only 600 miles. My car is a 2003, with 50,000 miles. It seems a little premature but ... I'm thinking I may have a sticky or frozen caliper.

Has anyone else experienced the same thing with the /03 Bembos?

 

do you notice more brake dust on one wheel than the other, that might help id if you had a sticking/binding brake.

I had the same problem on one of my previous vehicles, new discs (rotors) were warped after only 300 miles, the tech said that driving very hard then stopping and holding the brakes on, when they are very hot, can warp them. they were changed and i took it easy but these warped just as quick, changed them to a different brand, as a few other customers had had the same problem, and it was put down to a "bad batch" of discs. Didn't have any more problems.

 

Your problems are not at all typical. There are plenty of things to check.

You might have pad material deposition on the rotors. Perhaps the pads are crap?

I've not heard of such issues with the Brembo setup if you're using decent brake pads and everything else is OK.

Time to find a really good brake shop for some help.

I seriously doubt you're really warping your rotors unless you're tracking the car and using the hell out of your brakes.

Clean the rotors off first. Find out how many rotors are affected.

 

Thanks for the input, I too seriously doubted the warping idea, but ... then again ... the rotors are the size of a large pizza pan. I needed to ask.

I'm going to check the rotors this weekend for irregularities. I did a little work as a machinist in my younger years and still have many of the tools, one of which is a dial indicator which I can set-up against the rotors and check for square. Once done, and proven straight, I will take the wheels off and clean the rotors completely, change pads and reassemble.

Do you have any recommendations on cleaning fuild/s for rotors? I use Brake Kleen, because it was the only cleaner available from the parts store at the time.

 

I've read that it's not so much warped rotors as that they are unevenly coated in (tiny amounts of) pad material and/or have suffered patches of localised heating (such as posted above with the pads). The same articles tend to describe how to "bed in" new pads/rotors which reads like a process to anneal the metal and/or deposit the thin even coating of pad material (if that is indeed what happens). I am not any kind of materials scientist or whatever so although the articles sound convincing I do not know if they are true. Anyone?

For sure you need to mount new rotors on REALLY CLEAN hubs.

And I think not overtighten or unevenly tighten the lug nuts. (Avoid air guns left on who knows what torque.)

 

There are lots of sites about bedding in in brakes and the spotting that can occur if not done correctly, here is just one of the sites
Troubleshooting Information | EBC Brakes

Hope it helps

 

I know. Is it true, though? I mean, really, scientifically - as in provably - true?

 

I have first handed experience with my S-type and it's predecessor, an Infiniti. In both cases, pad binding material had transferred to the rotor surface in an irregular pattern both in the amount of surface coverage and the thickness of the 'coating'. The difference in friction coefficient between the bare steel and the 'coated' areas, plus lateral runout variations gave the classic pedal thump and steering wheel shake.

This material was removed by use of an abrasive wheel mounted in an angle grinder. There was NO need to turn the rotors in a lathe as this simply machines away expensive rotor material for no reason.

Root cause was poor quality pads, the problem never reappeared after swapping to OEM or top quality aftermarket.

 

Attached is a bulletin that lists some procedures that may help reduce or eliminate brake judder in your STR. We have had good success paying close attention to the rotor/pad installation and reducing the vibration.

I will add, at the risk of starting a firestorm, that in MY [humble] ;-) EXPERIENCE HERE, numerous aftermarket/performance parts for Brembo brakes have caused us headaches. In every case, cars have come to us after having the aftermarket parts installed and then suffering the poor longevity and quick starting vibration described, and the installers gave up. In one case, I think, the installation procedures in the bulletin helped quite a bit, but it usually wasn't fixed until the original Brembo parts were installed CORRECTLY. I knew it's a pain, but it usually works.

Like I said, that is my experience; others just love performance parts, so take it for what it's worth.

Good luck!

 

Steve, in your "humble experience here" .

Thank you for sharing. To the Brembo guys

 

First install Akebono pads. The best compromise out there for pads. Then cut your rotors. I know that Jaguar insists they be replaced but I fought the same crappy brake shudder for a long time until I backed up and just fixed the damn thing!!

45K miles later the turned rotors and Akebonos are still working just fine!!
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I have drilled and slotted discs and matching performance pads from brake performance parts with about 5000 miles on them and no major judder. Hubs were cleaned and lubed prior to mounting and calipers serviced. I get more feedback, feel through the steering wheel at light pressure and breaking, but up the pressure or stamp on them and they stop in a flash, great feel and no judder..hope that helps

 

Thanks for the bulletin. I'm replacing my Brembo rotors with aftermarket and Hawk pads on my xkr. Wasn't planning on measuring for runnout, but it sounds like a good preventative measure.

 

Thanks for the great input everyone, I have been looking around the aftermark and founda set of akebonno ceramic pads. I know these are hard pads, but I sincerely doubt any material transfer will happen in the breaking period. Anyone running ceramics on the street with success?

 

My car is a nonR but I'm using ceramic pads on all four corners. They're just great!