03 S Type 90k miles. Runs great in all respects. Except 2 steering issues: At 55-65 picks up a slight vibration in the steering wheel. Have had rebalanced several times. Could it be a bad ply or belt? The other issue is slow speed hard turning but not maximum there is a rapid vibration for a second and then it stops. Fluid is ok belts are good. My mechanic doesn't know where to start except to pull it all out and check each component.

 

Yes. Sometimes referred to as 'belt shift' or simply 'the tire has gone lumpy'

More likely to happen with an older tire but not unheard of on a new-ish tire.

Impact damage can cause a vibration as well. Hit any huge potholes lately?

Cheers
DD

 

Thanks DD. Lots of potholes in Maryland. Tires are a bit older. Next year will replace. It's only drive. Weekends so could be a flat spot I was told from parking. Thanks.

 

I actually have the same problem for many years. The steering on an S-Type R rocks when turning Left, particularly downhill or at speed and can only be prevented by touching the brakes. Some years ago my dealer communicated with Jaguar at Coventry and they admitted that this was a known fault; there was no recall because it was not considered a safety issue. The problem is that the steering pump sets too high pressures and then the system cuts out intermittently.
We changed the steering pump, hoses and steering rack with considerable improvement but not complete cure. it may be that we need to change the hoses again (which contain a valve system to prevent over-pressurising).

 

Does not sound true. Anyone else?

 

That's a new one on me too.

Mr. Rick- try moving the front wheels to the rear to see if the vibration follows.

 

Look for a tire shop that does road force balancing.
You can search from the Hunter website:

Hunter GSP9700 Wheel vibration Control System solves wheel vibration and tire pull problems that balancers and aligners can't fix

Dynamic balancing cannot detect all flaws which cause vibrations and road force balancing can tell the tech if the wheel is bent or tire is defective and causing the problem when dynamic balancing fails. I had to return a set of brand new Continental tires because three of the four failed the road force balance test recently.

If your tires are more than 5 years old or more than 50% worn you might just consider replacing them and not waste time/money balancing them again but I highly recommend road force balancing for this sort of issue when you cannot get a satisfactory balance from a traditional dynamic balance.