My car is shaking slightly when braking, and I sometimes have a squeal. I think it might be high time to replace the rotors and pads. I don't have the appropriate measurement tool, but from JTIS I can read that the Brembo discs only allow 1mm wear on each side (new 32, minimum 30). It looks like I have about 1mm wear on the rear discs, but the front discs look to be more than that.

Would you replace these rotors (and pads)?

Front:


Rear:

 

That looks like a standard disk..?

From the lip on the edge, it appears to have more than 1.0mm wear but the face isn't badly scored. The more important consideration is whether the disc is true or warped. I've replaced front discs more often than rears on X300, X308 and XK8's so the kind of different wear pattern front to rear you've noticed is typical.

No info or pics of the pads. Jaguar OE have 9.0mm thickness of pad material so you can check how much yours have worn. I usually replace at around 5.0mm.

The shaking could be due to sticking pistons in the calipers. Check they move freely.

Graham

 

The discs are the Brembo discs fitted to my XKR 4.2 2002. I think the next year they started with the cross-drilled Discs. I suppose ai could replace with cross-drilled if I wanted to...

Since most of the braking force is applied to the front brakes, it makes sense that they also wear the most.

For the pads, how do I measure this? Do I need to take off the wheels?
Checking caliper movement - how does one do that?

Sorry for being a bit of a mechanic noob. On the other hand, I'm a decent software engineer

 

Mine are cross drilled - other than massively increasing the replacement cost and looking good, I can't see a huge advantage. They are also more prone to cracking.

You'll have to remove the wheels to check pad thickness. I use a tyre tread depth gauge to measure mine.

Pistons need to be retracted to fit new pads. Many people just lever them back in but you can get a clamp to do this. Looks like a 'G' clamp with a flat face to press the pistons in evenly. They should move fairly easily. If excessive force is needed, it's an indication they may be starting to seize. This can happen if the rubber seals are damaged.

On a 2002, if you don't know exactly when the brake fluid was last changed, you might want to consider flushing it when you change pads.

Graham

 

I have a 2003 MY 4.2 XKR, so mine should have the Brembo's. The calipers look like this:



I believe this would be a correct (reasonably priced) replacement for me:
Brake Disc Front - C2N3428 | Jaguar XK8 - XKR | Jaguar | British Parts UK

But, another option would be to get a kit like:
Rotors on ebay - or would you advise against such an aftermarket kit?

Jaguar wants insane amounts for the C2N003428 rotors. Part sheet says $580 for a set of two. In Switzerland, I'd probably have to pay with my firstborn child.

Using the iPhone through the rims, I managed to snap some reasonable pictures of the front/rear pads. Do they need replacing?

Front:


Rear:


Thanks for the advice.

Brake fluid was controlled and topped up at the last service, about 9000km ago.

 

Yes - that's a Brembo caliper and those pads look well worn.

Same caliper as mine but I've got the cross drilled discs:



There was a thread a few months back on Brembo and it turns out there's a difference in disc diameter depending not only on whether it's XK8 / XKR but also if fitted with the optional performance pack. Best to measure your disc diameter before ordering replacements.

Graham

 

Graham is giving sound advice, but although I don't have an xkr, many owners find aftermarket rotors and pads instead of buying the OEM ones, those prices are high. I've had good luck with PerformanceBrakes on another vehicle, the rotors have been excellent on that one. You can have cross drilled rotors zinc coated in black so the edges and dimples don't show corrosion, which is nice if you've ever seen the untreated ones. I always trust what TireRack sells too in regards to brake components.

 

As written by Azeteg
Jaguar introduced the cross drilled Brembos in 2000 with the introduction of the XKR Silverstone in England, 2001 in U.S. Later in the year they offered them as an option on the XKR

 

Besides what GGG said, drilled rotors can not be turned like regular ones, and generally don't last as long since there is less metal and hence less heat dissipation. Really no advantages other than looking cool.

I am about to replace all 4 of mine over the next year. I do get brake shaking, and my rotors are too thin to turn. While always having non-drilled Brembos, I am leaning toward getting drilled (not from the dealer of course) as they seem only slightly more than regular ones. And primarily because they look cool and are exotic (exotic= I don't have them and never have had them before; sort of like an XKR till I got one)!

I think my current rotors are the original, and lasted 8 years / 115K miles (even mix of city and highway). I'd be content if the drilled ones can last half of that. Can anyone confirm how long their drilled rotors have lasted with smooth (non warped / non shaking) miles? or any particular vender / brand of drilled / non-drilled rotor that has done the years and miles?

 

Bill,

My 4.2-S was supplied and serviced by the same Jaguar Dealer from new and I have all the records. Still on the original Brembo drilled discs at 78k miles and all four are non warped with no scoring. It's on the third set of pads.

Graham

 

Thanks. Then I probably will go with the drilled. I'm all for the looks, but not if I'll have to replace them an additional time.

 

As written by Red1bw
Here's the advantages of cross drilled brakes they actually let the brakes cool down faster, that's why most of the high performance vehicles come equipped with them.

1. Cooling
   • When you hit the brakes, contact between the brake rotors and pads produces a lot of heat. Both drilled and slotted rotors help dissipate heat by allowing air to flow around the rotors and pads. Cooler brakes mean quicker stops and a longer lifespan for both your brake pads and rotors.
   De-Gassing
   
   
   • Heat isn't the only thing that builds up between your brake rotors and pads. The material that gets burned off your brake pads becomes a gas, which in solid rotors gets trapped between the rotors and pads and loosens the grip of the pads. Slotted and drilled rotors let the gas escape, helping further cool the brakes and keep firm contact between the pads and rotors. This helps prevent your rotors from warping over time and reduces "fade," the decrease in performance of your brake rotors as they age.
   Wet Weather Driving
   
   
   • The holes in a cross-drilled brake rotor give water a place to escape, increasing brake performance when you're driving in the rain.
   Disadvantages
   
   
   • Because of the extra machining required, drilled and slotted brake rotors are generally more expensive than solid rotors. Also, slotted rotors may warp or crack over time. This is because the hot gas from the pads gets trapped in the slots. As the rotor wears the slots shrink, creating less space for the gas. Cross-drilled rotors, on the other hand, are able to properly vent gas throughout their lifespan and should not warp.

 

I usually don't drive like a wannabe racedriver. I suppose only real track usage, with constant maximum braking before every tough corner, would benefit from the drilled rotors. I'm actually driving more like a 70-year old, even though I'm only half that age. The Jag XKR is not a track car! It is a very comfortable and beautiful grand tourer. It is best suited with the top down at 35mph. I think I'll stick to the non-drilled discs. The beauty of holes is alluring however...

 

Azeteg
I don't drive very aggressively either, but last year in a stretch of Wisconsin mountain type roads where there wasn't any driveways or other adjoining roads, a friend who drives a lotus and myself, ran about four miles at about 90 to over a hundred It really showed me it's potential. Never felt any brake fade what so ever and they were getting some heavy use.

 

I finally replaced all 4 of my non-drilled rotors with drilled rotors. I believe all 4 were the originals with 119K on them (they were about 3mm thinner than when new - so about 1 mm out of minimum specs), and the brakes had minor pulsing most likely due to slightly warped rotors.
The front rotors were approximately $190 for the pair shipped (rock auto, centric brand), and the rear were approximately $240 shipped (partsgeek, eurospare brand). I also changed all brake pads and emergency brake drums (approximately $100 for all 3 sets). Besides braking being much smoother, I do notice the first braking after a rain is very good, whereas before I pretty much had to consciously dry the brakes by pressing hard or by abs pressing hard / groaning when first driving a wet car. Plus they look way cooler.
So far I am very pleased with the short term results. Just beware when ordering anything for the braking system for the XKR, make sure the pads, and rotors are for the Brembos; as I notice many of the parts that come up are for non-Brembo XK8's....so know what your pad should look like (two holds for the pins rather than the traditional ears) and the needed front and rear rotor diameters.
Total cost for 4 new drilled rotors, pads, and emergency drums about $530.

 

You did really well with your rotors, I replaced all mine not long after purchase, as they had about 3mm wear as well, but my car had only done 48k.
Poor quality rotors or more likely really heavy (enjoyable) use from previous owner!!

 

I am going to put these on mine.

I had slotted ones before on the last xk8 and liked them

 

I'm trying to verify this right now - you wouldn't recall the thread or any other information about this, would you? Tried the search function but coming up mostly empty. Not a lot of info about this irregularity out there. Thanks.