Has anyone ever replaced their standard regular discs with perforated/ slotted/ cross-drilled or any such type discs on their X350? If so, what kind of disk pads are you using together with these disks and what kind of outcome have you noticed after the change to these discs and/ or pads?

I replace my regular X350 disks and pads almost every 24,000miles (40,000km) and I feel this is excessive! I am not a speedster, nor a sudden stopper, it is just that my XJ feels a little heavier than the 1.9tons advertised, hence the excessive force needed to bring it to a halt.

I now want to replace the front discs with drilled ones and hopefully match this with carbon-fibre or high performance disc pads and hopefully never replace them as frequently as I do currently.

Any views or what is the experience of other forumisters with discs and pads etc?

 

Seth it sounds as if you are spending good money needlessly. Pads AND discs every 24,000 miles !! That's excessive I think for a driver who says he isn't a speedster or last moment stopper.

I just replaced the right front rotor on my workhorse 1993 Dodge Ram van at 275,000 miles due to a failed caliper that ate it up after dragging the pads !!

Slotted or drilled rotors will give you a better initial bite, somewhat cooler running brakes, and extended pad life but your announced driving habits probably don't justify the additional cost for a quality set of such rotors and a cheap set could prove dangerous. The same goes for the use of carbon fiber pads as you'd see little difference and much greater cost.

 

The frequent replacements are mainly because the Jag dealership servicing my vehicle does not skim discs (metal rotors) to remove wedges at the top caused by pads sinking onto the disc upon braking. It looks like my rotors (discs) are not strong enough as they wear off (sink in) slightly at the top leaving an uneven surface at the top, and when I replace brake pads, the dealership also advises me to replace the rotors to prevent premature wear on new brake pads.

Apparently skimming of the disc could cause severe brake failure or at worst, they could crack upon emergency braking.

Since you put on such a high mileage before replacing your dics (rotors), are your brake pads not causing wedges on your discs? Or do you regularly skim them, and if so, how many times can I skim them (i.e., what's the minimum front disc breadth I must maintain) before further skimming poses serious safety risks?

How do other forumisters handle this issue?

Looking forward to your feedback.

Seth

 

Your dealer thinks because you own a Jag that you SHOULD pay the premium every time you drive in his door.
The pads DON"T ride right along the outer circumference of your rotor so they pretty much all will leave a narrow band of untouched rotor material at the outer edges.

Second, "skimming" as you call it does not lead to any sort of catastrophic brake failure as long as they are not "skimmed" beyond the recommended thickness. His statements to the contrary notwithstanding. I can't remember where it is but I'm certain that buried in the appropriate Jag service manual you'll find that minimum number.

Third, I would find your dealers choice of replacement rotors questionable at best if they are worn beyond the point they an be resurfaced after only 24,000 low performance miles. I would also question his choice of pad material since for your kind of driving a std. duty pad would be sufficient, or at most a ceramic to lessen the brake dust. For the rapidity of wear that you speak of I can only think of a fully metallic, and therefore highly abrasive, pad causing that kind of disc damage.

Wouldn't you think it a little strange for Jag to warranty something (not pads) that wears out every 24K miles?
If you must, buy yourself a set of quality rotors (although I'd check to see if yours can be safely resurfaced as I'm betting they can) along with a brand name ceramic pad and do both somewhere other then your current servicing dealer.

 

Your dealer has a good one on the hook! Unless you are really a lead foot in denial, the components should never wear out that fast. Skip the slotted, drilled stuff. just buy quality rotors and pads.

This skimming you refer to is called "turning" or "machining" the rotors. It is perfectly safe as long as you do not exceed the minimum thickness that is probably stamped on the rotor. Any rotor should be able to stand turning once unless it has been abused.

---------
Believe none of what you hear and half of what you see!

 

My '92 XJ6 has 215,000 on the original front discs, and yes, there is a lip where the pads don't touch.
I never turn (skim) (machine) my discs. Here's advice I was given once and it made such sense that I have never turned a disc since.
By the time your pads wear out, the disc has a "work hardened" surface, usually with minor radial ups and downs (mountains and valleys if you prefer). If this surface is machined flat:
The mountains are taken down to the valleys.
The surface of the valleys are still work hardened, but the mountains just had their work hardened surface removed, leaving softer metal underneath.
When new pads are now placed on this nice and flat surface, the old mountains will wear faster than the valleys which still have their work hardened surface.
In 10,000 miles, the old valleys are the new mountains and old mountains are the new valleys.
All you have done is help wear out your disc faster by removing hardened surfaces.
Just replace the pads until the thickness of the metal by the lip is less than the minimum allowed. This is often stamped right on the disc. If not, it's in the shop manual.

 

About the drilled/slotted rotors....don't do it unless you are ok with the considerable noise they make when stopping.

I did it and while they look great they suck due to the noise. I will be going back to stock rotors next time.

 

This is excellent piece of advice I will now keep for life. What is the minimum thickness recommended, and where is that specification written?

 

Your advice and MarcusJames' pursuaded me. Thank you.

PS. Your car's paint-work looks spotlessly clean and neat. How do you keep it so nice?

Here in Joburg, our parking bays are tiny, and it is difficult to keep the paintwork spotless without scratches. That's because other drivers open their car doors wider as if opening to let an adult African elephant to get out! As a result, my car's body and paint work has bruises and scratches. And despite parking very far away from the entrance in open spaces, they still follow me! I guess my old lady's still so attractive that people still come to park nearer so as to have a good look at it.

 

Seth,
I fixed that for you above. lol!
Vector

 

That does seem excessive, at first blush at least. But there are so many variables involved.

For example, if most of your driving is in city traffic the brakes will naturally wear out faster. Likewise if your driving involves lots of downhill braking.

On the other hand, I'm well over 100k on my present set of pads. However, I do a great deal of highway driving where I rack up tons of miles without ever touching the brake pedal.

Then of course we have all the differences in friction material thrown into the mix !

So, 24k brake pad life *might* be normal for your car and your driving conditions.

Cheers
DD

 

Is your dealer fitting Jaguar approved rotors ?

Over a period of time my Jaguars have done over 300k and did not wear their rotors much.

I am a gentle driver, but so are you.

Ok, so I live in the UK, but genuine Jaguar rotors should not be expensive, and should last much longer than 24k miles.

You must be able to get Jaguar approved rotors in the US.
Oterwise make some enquiries for rotors in the UK, but ask for brake discs.

I agree with other members, you don't need drilled brake rotors (or harder pads); save your dollars and get some Jaguar approved parts.

Please remember the main parts between you, the pavement and an accident are your brakes and tyres; my advice is don't economise on safety, get approved parts fitted.

As others quite rightfully note, skimming, as we Brits call it, is fine within the manufacturers limits. Although I wouldn't expect any Jaguar approved outfit to condone skimming.

Very best wishes Rojie

 

Nice Pics!Good taste in tires too.I have a question though---are the rotors by ATE?If so which pads are you running with them?

My reason for the question is that I run ATE rotors with Akebono ceramic pads on my Subaru Outback (with Continental DWS tires) and they are quiet and stop very well.On the basis of my Subaru experience I was thinking of going with ATE/Akebono brakes on my S-Type.
I should point out that using factory pads with the ATE rotors was noisy.

 

It matters not whether the rotors are Jaguar approved or not. As long as they are quality. Buy known name brand quality. As far as I am concerned, you should turn the existing rotors or replace them. I don't buy into this work hardened theory. If you put new pads on old rotors, the pads must seat themselves into the peaks and valleys and you will have crappy brakes in the the interim.

I personally use new rotors each time. They are not that expensive.

IMHO. YMMV.

 

Work hardening is very real. The Raybestos and StopTech web sites are possible sources of reliable information on this and other brake related matters.

While there are rotors of all qualities available in the aftermarket, when someone chooses to buy Jaguar rotors they are assuring themselves of replacing like quality with like quality. Thus, they are choosing to do so in order to eliminate guesswork.

 

Hi everyone,
I have a question on skimming/machining rotors. When you replace new pads and if you don't machine, doesn't it make a noise when you braking? Specially at low speeds and coming to a complete stop. That's what my mechanic told me. He said when there's an uneven surface with new pads it makes a noise. It had happened to me when I replaced my brakes couple of months back. Any ideas how to get rid of it without machining it?

 

And they are also choosing to pay twice as much. It is not like Jaguar actually makes the rotors. I put the same quality Beck Arnley rotors on my car for a heck of a lot less. Work hardened rotors should probably be replaced.

 

Nope.

As I said, IMHO, putting new pads with the old, unturned rotors is folly. IF they are work hardened, replace them and the pads.

 

Yes, I do a lot of city driving, down and uphill with innumerable speed humps, potholes and reckless drivers ala Mumbai roads!

I will no longer skim them to allow hardened surfaces to reamin intact.

Thanks a lot for your advice.

 

I guess my Jag service dealership shares your views as they too recommend replacement instead of skimming! Their sales targets will be significantly reduced for I will never replace them until closer to the limit. By the way, what is the thckness limit? Where is this written?