Hello all. New to the forum and to Jaguars. I purchased a 2012 XF portfolio that had been leased by son that had 27,000 miles. Car was certified pre-owned. After several weeks I would notice severe steering wheel wobble when applying brake at a high speed. Dealer said it was due to extreme corrosion on the front rotors. I had the rotors replaced (they would not do it under warranty) and the problem seems to be gone. I have owned cars for almost 50 years and have never had to replace a rotor because of corrosion, especially a rotor with only 29,000 miles. I did inspect the old rotors and the surface was corroded. The car is driven almost everyday for 75 miles. I cannot see anyway to stop corrosion. I was told by the mechanic that the rotors could not be turned because many times that causes dimpling on Jaguar rotors. Has anyone else experienced this? The next time that I need brakes & rotors is there another manufacturer that is recommended? I have read good things about EBC products. It seems to me that there is a problem with the Jaguar product if it is going to corrode the way that mine did.

 

Could be the area you live in with the salt on the Winter roads.
I have bought from R1 Concepts with excellent results.

 

Your dealer is an idiot. All rotors corrode- they're made of cast iron. There's always rust spots on rotor surfaces after even a light rain. Like you, I have never replaced a rotor for surface corrosion nor would I.

Most probably the brake problem was caused by pad material being transferred to the rotor friction surface. It's easy remedied with a rotary abrasive pad on a drill or angle grinder.

 

Corrosion can pit the surface of the rotor but that should not affect braking.

The wobble you felt was most likely caused by either a seizing caliper or uneven pad material deposition. Since replacing the rotors cured the problem it wasn't the caliper although to replace the rotors requires removal of the calipers so maybe the caliper was freed up at the same time.

Modern rotors are not thick enough to warrant resurfacing. You get better value fitting new ones.

Had you known beforehand you could have tried rebedding the brakes like this:

http://ebcbrakes.com/about-ebc/faqs/

Faq 9.

and that may well have cured the fault, but maybe not. I'd have tried it before replacing the rotors.

 

Probably not a good idea to do it this way. Parallel disc faces are essential for proper pad contact. Better to use the brakes very hard to try and clear this up or fit new discs.

 

Please voice your concerns with 3M and see if you can convince them to stop selling their kits.

3M Roloc Brake Rotor Surface Conditioning Disc Starter Pack 1410

Virtually every brake shop uses something similar.

Good luck.

 

I've been meaning to post for some time about this phenomenon of resurfacing brake discs.

It's not something I've ever came across here in the UK at any time, not saying it doesn't happen, but in all my years never heard tell of it.
I guess it must be an American / Canadian thing.....could be wrong??

We usually just replace them with new ones as required, although generally speaking we seem to be able to get perhaps 2 or even 3 sets of pads to one set of discs without issue, and still live to tell the tale!


On the subject of corroded discs - I've seen many discs with surface rust ( nothing to worry too much about ) and also a few with corrosion on the leading edges, if that's what you're talking about?
Over here the environment that they exist in it's more likely to happen than not at some stage

 

No, that's fine. 120 grit won't take any iron off.

But, how much is your labour worth? By the time I pay someone to take the calipers off I'm putting new rotors on but you are right, buffing the rotor faces is another way to address rotor "warping".

For me if ten hard consecutive stops won't fix the brakes I'm fitting new rotors and probably new pads. You go ahead and grind your time away on those iron rotors worth a few bucks each...

8-)

 

You might machine rotors if you are fitting pads of a different brand but generally speaking it's a mugs game with modern discs. The specification for minimum thickness after grinding makes it uneconomic to bother. In the old days it was standard practice.

 

I don't think I'd ever call it a mugs game, that's probably a bit harsh, although not something I would do myself, each to their own......their vehicle, their car, their choice.
For me, the time involved, the hassle etc as against any cost savings just wouldn't be worth it, but as I said, it's not common over here as far as I know

 

I first saw rotor resurfacing being done in the late 60s/early 70s when disk brakes started to replace drum brakes as standard equipment on cars here. It was presumed (incorrectly) that if brake drums needed machining every now and then, so must rotors. Of course garages and machinery manufacturers jumped on the bandwagon and it soon became standard practice to machine rotors at every pad change.

50 years later, and despite the mountains of evidence proving that the practice is not necessary and never was, there's still plenty of shops and owners that insist on doing it. Usually in the name of 'safety' Anything can be justified in the name of 'safety' as we've seen in recent discussions.

The last rotor I had machined was in the mid 80s, when the penny finally dropped.


And yes, we also usually go 2-3 sets of pads per rotor. The corrosion issue the OP mentioned is simply a dealer that needs a smacking.

 

In the USA machining/turning/resurfacing brake rotors is a bit of a throwback from another era. In the 'old days'....1960s-70s-80s... the brake rotors on USA made cars were usually quite thick and quite expensive. It was routine practice to resurface them as they had enough 'meat' to tolerate the reduction in thickness. What's more, new rotors were often well over $100 each....sometimes more like $150 each if you had a big ol' Lincoln or pickup truck or such. You could bring your rotors to the local machine shop and have 'em resurfaced for $10.00 each! It was a no brainer.

(Those were the days when almost every local auto parts store also had a machine shop 'in the back'. )

If you were having your brakes re-done at a repair shop, resurfacing the rotors and/or drums was routine practice and simply included in the price. Installing 'new' friction material on an 'old' surface was considered bad form....and still is, in many circles.

In the 1990s we started going to thinner, lighter, and generally less expensive brake rotors.....so resurfacing them didn't seem so attractive and often isn't even possible without going beyond legal limits. What's more, foreign made brake rotors.....even for the older cars....are often a mere a fraction of the price that the originals were 25-30-40 years ago

Cheers
DD

 

on our XF SC we had a similar deal last year. We don't drive the car during the winter and the rotors get really rusty just sitting. First time out I was playing and hit the brakes really hard..from that time forward it shimmied bad every time I applied the brakes hard. Had it scheduled to go in for all new rotors and ordered them. They didn't come in before our vacation to Austin. After a week in 95 degree temperatures and horrible stop and go Austin traffic, the brakes worked smooth as can be and have not had a problem with them for over a year...

 

Brake discs are made close to minimum feasible thickness to eliminate excess weight and where weight savings make the biggest difference: rotating unsprung weight.

One set of pads with semi metallic linings are very likely to reduce disc thickness by more than half the allowed amount. Resurfacing would reduce disc life even further and so is not recommended unless the issue requiring resurfacing occurs during the life of the first set of pads.

I say machining is a mugs game because doing so during the life of a set of pads means you pay the labour for a complete brake reline and end up with a set of used brakes. Plus you pay for machining.

Often people don't calculate the routine repair costs correctly. You do if you expense them. The cost of a brake reline early is merely the opportunity cost of bringing forward the repair, not the cost of the repair itself which you incur anyway just a little later in the cars life.

A $1,000 brake repair performed 2 years early only costs around $40 in lost interest earned on that money and less than $200 if you have to borrow on your credit card to afford the outlay. It does not cost an extra $1,000 during the service life of the car. The opportunity cost of throwing away discs before they're all used up is tiny.

Reusing old discs may save you a very modest sum but at an increased risk of having an accident, perhaps a serious one.

 

some of what you say makes sense and can be agreed with, the above quote - Not so much!!

A set of pads and discs all round could be in the region of £600, whilst a set of pads all round ( if the discs are ok ) would be around half that, so £300 inc labour
This is not an insignificant amount of money to a lot of people.

Safety is not the issue you make it out to be and throwing away perfectly good discs is just plain silly, but as I've said before along with others, each to their own

 

My point is the thrown away cost is not that cost difference. It is the opportunity cost of paying that today rather than in two or three years time when the job has to be done anyway. The actual thrown away cost is the opportunity cost of throwing away a half worn disc which at its maximum is half the new cost of the replacement disc. It is never the case that the cost savings equals the price of the new discs, the maximum loss is the value of the thrown away discs. Then you also deduct from the presumed loss the costs of machining and the labour of taking the caliper off twice instead of just the once. ( very few mechanics replace pads without popping the calipers off ).

This is how property damages are calculated so it's not only correct accounting it's the law!

 

Lol, I had a long analogy written out and examples etc etc, but really can't be bothered.
Suffice to say, you do what you want to do and what you think is right for you, and the rest of us will do what we think is right for us.
So much easier, so much quicker

 

I think your calculations of car ownership and maintenance costs is even more flawed than your understanding of standard OEM (vs. half baked indy) maintenance practices. That's pretty scary.

If I own a car for ten years and due to high usage need a set of pads every year, using the OEM system of rotor discard thickness I might go through 5 sets of rotors.

Using yours, I'd go through 10 sets.

 

I was going to make a similar point Mikey, with an outline of mileage vs years vs brake costings etc, then gave up as it seemed pointless.

 

I replied knowing full well it was pointless wrt convincing our misguided friend. Similar to the other discussion about rotor replacement, it's the OP and others asking the same question that deserve a clear and well substantiated answer.