idrive this car above 30 mph and slightly start to brake it will judder very badly, all the way up to 90 plus. brand new disc pads bearings and tyres rims etc all checked. what can it be? im getting vexed

is it possibly
D bushes
front links
front lower arms
or thefront track control arms ?
will apreciate your help thanks

 

Let's eliminate the wheel bearings, tires, and rims since you said they all check out OK. Among the other possible causes that you cite, since the judder only happens when you start to brake and it continues from 30mph to 90+mph, it seems to me that your problem is most likely caused by the brake rotors.

Some people will tell you that your rotors are warped and need to be replaced. Although extreme heat can cause rotors to warp, in most cases vibration is more likely to be caused by an uneven build-up of brake pad material on the rotor that causes the pad and caliper to move up and down as they grip the uneven disk surface, which you feel in the steering wheel as vibration, shimmy, or judder.

When you had the new pads installed, if the installer did not machine the rotors to remove the build-up left from the old pads and make those rotors smooth and true as new, then that's where I would start. Have your rotors checked for build-up and run-out (wobble in and out while spinning) and have them machined, if possible. Even if your rotors have sufficient thickness remaining to be machined (also called "turned"), my experience is that you're better off to buy brand new rotors.

If the rotors aren't the cause, then I'd have a good front-end mechanic do a thorough inspection to see what parts are worn and need to be replaced.

If this was helpful, please press at the bottom right.

Stuart

 

hi stuart, talking about the rotors there new, the judder is under light braking at most speed

 

Hmmm, chasing down similar issues on my X358

At around 63k miles there was play in the suspension bushes so these were replaced both front and rear - no difference
New tyres fitted - no difference
Wheels balanced and re balanced using Hunter roadforce balancing - no difference
New front brake pads and discs - seemed a little better, but still there and now back as bad as ever.

Trying to get a swap of a known good set of wheels to do a few miles in to rule that out!

Personally, I'm wondering about hub run out and or wheel bearings ( although there are no symptoms )
I have heard of others with similar issues also with no wheel bearing symptoms who have changed them and its resolved the problem??

Going in to Prestige Jaguar on Thursday for a thorough check up.....I need this fixed!

 

Were the brake pads and rotors on all 4 wheels replaced by a Jaguar dealer using genuine Jaguar parts? If not, the problem could be caused by aftermarket parts or the installer cutting corners on the installation.

Even though they're new, I would still have all 4 rotors checked for excessive runout before getting into the suspension.

Here's an excellent article on brake judder causes and solutions. It's too long to reproduce on this thread, but definitely worth reading: http://www.ferodo.com/en-gb/Technica...n-Problem.aspx

Hope this helps,

Stuart

 

I had the same kind of light judder under braking. The dealer replaced the front rotor disks and the brake pads and that fixed it. However, it came back in about 5000 miles, at which time the dealer replaced the front rotor disks again. After than no more judder for the past nearly 20K miles.

Not sure what the issues were as my XJL never seen any sustained hard braking that could warp a rotor.

 

right im changing the track control arm bushes and the lower arm bushes in next few days also changing the front rotors under warranty aswell, then hopefully it will be good as new again, not very expencive for parts will change the rear aswell then get it aligned all around