HI,
my jag was vibrating when braking since I bought it.
( Beside this effect, the ride quality is perfect.)

I suspected the front brake disks to be the cause, so I replaced them with new disks by brembo. ( but it's not the brembo-brake on my car.)
I cleaned everything perfectly, so there's no problem on workmanship..
I reused the old brake pads.

Unfortunately, the rattling/vibration is still there.

I tried to find out, whether left or right wheel causes the rattling, but I didn't find I way to locate it...

I measured the axial run-out with my old disks 6 months ago. I was in spec there.

What should I do to locate the origin of my rattle ?

 

My wife's Chrysler Town & Country LTD was doing the same thing. I changed her brake shoes with some premium shoes and the brake shutter was gone. I don't know if this will make any difference with yours as I've not had any brake issue with any of my past Jags, but I thought it worthy enough to mention. Best of luck.