So did all 2000-2003 xj's come with 325mm fronts? That is, excluding the R1 and xjr100.

 

No, mines a 2000 VDP (with R pkg) and mine came with 305's. I would guess its an option pkg.

 

John Amaradia,

Maybe this post is too old but here it goes;
I have a 2001 Jaguar X308 3.2 V8 Executive Sport and I just checked to be sure before ordering new discs. My front brake discs were 305mm / 12 inches. I think the 325mm discs would not fit within the stock brake calipers.

 

Obviously not as the calipers have to sit 10 mm further away from the hub cetre. These are the calipers for 325 mm discs:

 

The calipers and pads are identical between 305 and 325 rotors, the only differences are in the caliper mounting bracket.

 

Oh didn't know it was only the caliper mounting bracket, thanks!

 

Once rotors get to the glowing stage warpage is common. That’s the reason a lot of us go to full floating discs. While you might get get away without warping the overheated rotors with a proper cool off lap. I got tired of replacing the rotors.

 

Why does it happen? Possibly under braked for the platform, hence the bump in diameter.
The warping was pretty much solved with one member posting the warped disc phenomenon years ago, coming down from speed to a stop and hold of the discs. Next repeated brake from speed had introduced the warped bumping pedal....holding the hot rotor had created a hot spot and the warp. Bigger brakes is for me the very best upgrade on any car you can do, just don't pin hot discs!

 

That's an easy one - the part of the rotor where the pads are in contant cools at a different speed to the rest of the rotor, which leads to warp... that's not the *only* reason for warp, but in the specific scenario you describe that's what's happened. In cars that use the regular calipers and pads for the handbrake (most cars these days), parking the car with the handbrake on after a spirited drive can easily warp the rears.

 

Any X308 with the 305’s are definitely too small. It’s just like the 98 X308’s that have the smaller front diameter wheel bearings. It’s just too small for the car. When I rebuilt the entire front suspension and subframe of my 98’ XJR about 5 years ago, I replaced the knuckles with an 02’ XJ8. The had the larger wheel bearings.

 

When I bought my first X308 in 2009 it was a 4.0 Sovereign and soon after buying it became apparent that the front brakes were warped. The dealership wouldn’t let me test drive the car because I was only 22 and they didn’t think I was in a position to buy the car. Anyway, after that regardless of what I’m driving when stopping from high speed I always aim to leave a big enough gap between myself and the other vehicle so I can allow the car to crawl forward and not create a hot spot on the discs.

My current XJR has warped discs and I will be replacing them soon, but this time I was able to knock that off the price.

 

or you could put the car into neutral (assuming you’re on level ground ).

 

I was taught to leave automatic transmissions in D and hold on the brake if stopped for shorty periods like traffic lights, if stopping for longer periods then take it out of gear. It says as much in the X308 owners manual, plus on the NA cars with the ZF5HP24 unit it helps avoid damage.