Hi, I have a 1997 Jaguar XK8 Convertible that recently had a leak from the power steering, we found the leak (a blown gasket in the middle of the pump), and ordered a brand new power steering pump from Jaguar.
My mechanic changed this today, bled the air out, and everything seemed just fine. Backed out of his garage, and drove home.

On my way home I noticed the steering started to get occasionally hard, but I could still drive the car, since there was no really big turns on my trip.

When I got home, I had to turn 90 degrees of the road, wheel really heavy, I stopped, popped the hood, and checked the power steering fluid. Level was ok, no air-bubbles, all looked just fine. No noise from the new pump either.

I can tell, that all hoses in the power steering system has been changed recently, everything except for the steering rack.

Oil we used, Gulf Multi Vehicle ATF. (Recommended by Gulf)

Can anyone figure out why I have a rock hard (muscle) steering??

 

I've moved your post from the General Tech section to the XK8/R section for better visibility/response

 

The wire connection from the Speed Controlled Steering Module may have become disconnected from the Steering Rack. If so, the steering would be Hard at all times, not just at highway speeds.

 

Sometimes the valve in the reservoir goes bad, and that will cause this problem. I would lean towards the rebuilt pump though......I have had a few bad ones of many makes.....Just spit ballin.........Mike

 

I have noe idea what happend, but my mechanic came over, looked at the servotronig sensor on the rack, nothing changed. Then he started to increase rpm with the gas pedal, and suddenly system worked again. I guess there must have bees something blocking the system, causing the power steering not to work.

Yesterday I had a long ride with no problem on Norway's Independent day.

 

Follow up to my original post > I cant believe its been a year since I started this. I've moved from 92630 to 92592, its taken a year to sell the old house
find a new house, do all the repairs & finally set up the work shop
In the heat of making trips back and forth I decided to just for the heck of it to poor in the additive I got off Ebay.
It worked almost immediately
, I was shocked and super happy, I thought for sure I was going to be replacing the p/s pump.
So with that knowledge I took the car to my new neighborhood mechanic
(Redhawk Auto Service , Temecula ,CA)
They did a complete system flush with a cleaner then drained and refilled with their p/s fluid.
Its been working perfectly ever since ..