Hi,
I have 2 advices from 2 different sources:
- when my Jag did 32,000 my brake pads worn out and was advised to replaced both discs and pads as they said my brake pads touched disc and so the disc was damaged.
- last week I got my Jag serviced for regular 10,000Km ( it has done 55,000Km up to date) and was told that I have to get my brakes replaced (both discs and pads), I was surprised when the service guy told me that with European cars both discs and pads need to be replaced every time the pads worn out regardless the discs have no damage.
Can someone help me to clarify which one is correct for me to act accordingly as you know the cost to replace the pads is completely different from the cost to replace both pads and discs both front and rear.

Thanks in advance for your knowledge and sharing.
L
My Jag is XF 2010 X250 Luxury

 

Yes and no. Modern disc brake pads use metallic linings which wear discs more quickly.

The discs may be within spec when the first replacement pads go in (second set on the same disc) but the discs will wear below spec before the fresh pads are worn out.

Brakes work by generating heat from momentum, the pads wear to generate the heat. The discs dissipate that heat to keep the pads from burning up. The thinner the disc the hotter it gets and the faster the pads wear. New discs are always a good idea for best brake performance.

Furthermore, new pads work best when bedded in. Putting new pads on old discs can double the bedding in time, or even longer, during which time the brakes are nowhere near as effective as they should be. New discs are machined as for new engine cylinder bores in order to bed new pads in quickly. Even if you keep the old discs good shops will insist on machining these although they think this is to cure "warps" which is hardly ever the case. By the time you pull the old discs off to machine them (although some shops claim they can do so on the car, the backing plate has to come off first) , pay for the machining and re installation you may as well have paid for new discs.

Finally, if you replace the pads with the same type there is less bedding in to do but if you change pad types then bedding in will take much longer as the brakes need to transfer new pad material into the surface of the disc before maximum braking force is achieved.

Check this faq at a major UK brake maker website:

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

Scroll down to the bedding in question.

Also, Stop Tech web site has excellent technical papers on brake technology.

You should not need new brakes within 10,000 km, just btw. If you mean you've done 23,000 km then your rear brakes will be due for a change soon and, assuming at 32,000 you did just the rears then new fronts will be needed. If the fronts were done at 32,000 then no way you need new fronts at 55K. If you replaced the fronts at 32,000 km then either something is wrong or you got ripped off, fronts are good for 50-60K.

Rear brakes wear at rates of between 25,000 and 35,000 km and front brakes about twice that. If you replace discs routinely you can safely run your brake pads down to less than 2 mm remaining since it doesn't matter if you misjudge and score the discs. Your service shop will be advising based on industry estimates of brake life remaining which are very conservative. Ask how much lining depth remains and then an estimated percentage. Anything more than 2 mm and 10% will mean your brakes will likely give you another 5-10,000 km.

 

In isolation this generalized statement is false. The rotors should be judged on their own merits to decide if replacement is required.

 

If I read this right, you had all discs (rotors) and pads renewed at 32,000 km, and 23,000 km later the dealer is recommending new pads and rotors again.
It is very unlikely you need new rotors again, and new pads should be enough. But you should at least have the rotors machined, so the new pads have fresh surfaces to bed into. Many dealers will try to talk you into having new rotors every time you have the pads replaced even where the rotors are nowhere near worn out, claiming that the existing rotors will be worn out before the new pads are worn out so best if you renew them now. Sometimes this may be true, but often it is not. If I were you I would take the car to a specialist brake shop and have them assess the condition of the brake rotors, in particular how far have they to go before they reach minimum legal thickness. Also, you can buy replacement brake pads over the internet for a fraction of the price a dealer will charge you for OEM replacements, and depending on which brakes you have you can get much better pads than the OEM replacements - less noise, a lot less dust, and a lot better wearing.

 

There generally should be no need to replace pads and discs at every change on this or any car.
Obviously various factors will come into play such as driving style and how you use your brakes.

If my memory serves my Audi A6 had the original pads plus 2 sets before replacing all pads AND discs at around 86k miles
There will be a minimum thickness spec for your discs, any good dealership should be able to tell you exactly how worn they are in percentage terms

At 32k miles I'd be amazed if you had to replace pads AND discs all round, and absolutely flabbergasted if you had to change pads AND discs again at 55k miles

IF you've worn your pads so low as to score the discs, ( metal to metal ) then yes, its time to replace them.
It does sound to me like you're being conned though and worth getting a 2nd opinion


EDIT - I've just re read and its not 32k MILES but 32k KM, so approx. 20k miles for new pads AND discs
Then again at 55k KM NOT miles, so approx 34k MILES


Someones having a laugh I think, definitely get a 2nd opinion

 

There's 3 reasons to replace discs:

1. bad surface scoring and/or cracks (due to running the pads down to the metal back plates)
2. excessive runout (warping)
3. below minimum thickness (worn)

The 'service guy' is probably adding another of his own:

4. to increase his bonus

Ask him to show you the recommendation that "........ both discs and pads need to be replaced every time the pads worn out regardless the discs have no damage" in Jaguar technical documents. He will NOT find it!

Graham

 

In my own experience, new pads on existing discs take a few hundred miles to bed into the faces of the existing discs. During that time, you have to press the brake pedal a bit harder to get the same retardation. The brakes are still legal but you just have to push a bit more until the pads are bedded in.

With new pads and discs the bedding-in process is still needed but usually takes far less miles.

Discs have a minimum thickness, and when this is measured on your car, and compared to the mileage since discs were last fitted, the mechanic can calculate a likely mileage when this minimum disc thickness will occur. If that is fairly close, it is normal practice, when pads are worn out and the discs are near their wear limit, to replace them at that point rather than wait until the limit is reached.

 

At what percentage of wear do wear sensors engage and is this an electronic message for 2011 XF?

 

According to the workshop manual, at 75% worn.
And yes, it's an electronic message.

Here's what the workshop manual says (on page 610 of my copy):

BRAKE PAD WEAR SENSORS
When a brake pad incorporating a brake pad wear sensor is approximately 75% worn, the sensor wire within the pad material
is worn through and the brake pad wear sensor goes open circuit. When the instrument cluster detects the open circuit, it
illuminates the amber LED (light emitting diode) in the brake warning indicator, displays an appropriate warning in the
message center and sounds a warning chime.
Refer to: Instrument Cluster (413-01 Instrument Cluster, Description and Operation).

 

Hi Oz,
I did not see any message . Do all XF series have such auto message warning?

 

Hi Jagular,
Thanks for your info in details and it helps to clear my confusion.
I have rear discs and pads replaced at 32,000km at Jag dealer service cost $1000 AUD for orginal type( in July 2013).
This time at 55,000km (in May 2015), I was advised to have both rear and front discs and pads to be replaced. I searched and got 2 quotes from outside where 1st for aftermarket type cost $1500 (both rear and front discs and pads), 2nd quote for $2700 original type (for both rear and front disc and pads). Both of them said the car need rear and front replaced.
I am a lady and know nothing about these things.
Should I go for after market type or original type? should I go for European type or Australian type?
Thanks in advance for yours and others who spent to advise and share info.
L

 

Thanks for your opinion Jim.
I m getting another check from 3rd source today. Will see how I go since I got lots of information from you guys to back up with.
Kind regards,
L

 

Just as a backdrop, can you please advise the following........


1. What type of journeys do you typically take? Are they mostly many miles on motorways / freeways, or generally mostly stop / start and around town.
2. I for one assume you are NOT tracking / racing the car from red light to red light and HEAVY on the brakes all the time.


Basically, an idea of your type of driving style, type of journeys, roads used etc as well as how you use your brakes should help to give more of an insight.


My local Independent uses PAGID pads and discs ( I believe they may be OEM fitment too, but should check )
I've used PAGID on my Jaguar XJ X358, my sons 2 X types, as well as my Audi A6 and my old VW Passat, all with excellent results.

 

I'm going to make a post into your particular regional section to see if we have any local members that can help.

There may be someone close who can either have a look and advise and or, be able to recommend a trustworthy local Indy for you

 

Yep. If you never saw any such message either your brake pads are not yet down to the wear sensor(s) - most likely scenario - or there is a malfunction in the sensor(s) and/or system (unlikely). Most problems with these sensors and the system are 'false positives' ie you get a warning when the respective pad is nowhere near 75% worn.

 

I live near CBD so travelling short distants on 40km- 60km/h zone using brakes a lot more than people using free/highway. I think it run about 10,000km per year. Don't think I have any chance to race

 

What exact model of 2010 XF do you have? Especially which motor?
The brakes, especially the front brakes, vary from model to model, and if we know the model we can point you at the proper brake pads to buy.

 

It is XF3.0 V6 Lux. That's all I know. what type of brake? I don't know, never replaced front brakes, rear disc and pads were replaced by Jag dealer so I believe it's original.

 

pls tell me more about this " you can get much better pads than the OEM replacements - less noise, a lot less dust, and a lot better wearing."
I live in Melbourne Australia.
Thank you.

 

Again, it depends a lot on exactly which front brakes you have.
I fitted Power Stop Evolution Ceramic brake pads to my old 2010 XFS and they were really good - good progressive feel, plenty of braking power, good fade resistance, no noise, very low dust and very low wear rate. But the front brakes on that car are/were the "performance" brakes with 355 mm rotors/discs, as opposed to the standard 326 mm front rotors. The rear brakes are the same (also 326 mm but a completely different shaped pad to the fronts) on all 2010 XFs except for the XFR, so the rear PowerStop pads I got for my XFS would fit your car as well. However, PowerStop don't make brake pads for the front 326 mm brakes, they only make them for the front 355 mm brakes.
So you need to check exactly which front brakes you have. I'm 99% sure that your car would have come stock with the 326 mm front brakes, but I think you could order the 355 mm "performance" brakes as an option for the 3.0 petrol V6 delivered to Oz. You definitely could for the 3.0 V6 diesel, and the Oz version of the XFS (with the higher tuned 3.0 V6 diesel) always came with the 355 mm front brakes.
The easiest way to check for sure what size front brakes you have is to remove one of the wheels and have a look down the side of the brake caliper. The size number is stamped into the front edge/side of the caliper, so on yours you will see either "326" or "355". Then you will know for sure exactly which size front brake pads you need, which in turn will dictate your available options. Of course if you actually have an XFS then you can be 100% sure that you have the 355 mm front brakes!