I had my pre HE steering rack re conditioned by a reputable company as part of a re commission after 25 plus years off the road. The suspension and bushes are all new too. The car drives beautifully now but I sense a steering that doesn’t really self centre. It makes it slightly tiring to drive as it’s hard to keep it on a perfect trajectory. Now don’t misunderstand , this is a very very good car with lots done to it. All new tyres and tracking apparently good to spec from a book. Any suggestions much appreciated. Thanks
I think that’s an alignment issue. Did you make sure the proper mid-laden tools were used when the car was aligned?
Hi there and thanks for the reply. I can’t recall reading about midladen tools , however it was
Done on all four wheels on proper alignment jig I will re read the book and check what it says. However I would agree it does seem like toe in or out. I read on another forum something about preload on steering rack ?
The rack needs to be centred using the pin into rack to ensure it is aligned when toe is set.
The centering of the steering rack does not effect how it drives down the road. It only insures that you have equal turning radius in either direction. This can be easily verified by looking at the tie rod threads. You should have equal amounts showing on each side. As far as toe, in the late 70’s, Jaguar published in some shop manuals for the V12 to have toe out on the front. This was a mistake as the car needs toe in. With toe out, you cannot make it follow a straight line. If you got a printout of the specs they set it to, you can easily verify. The tires will wear on the inside edges if they are set with toe out.
Thank you for the above contributions. Being a 1976 car naturally I need to check that the data is compatible. I will check my various sources for further information and report back. So the general consensus is that the self centring will be down to the geometry nothing to do with the rack ?
The major contributor in self centring is Castor. The greater the Castor angle you have the more willingly the wheels will self centre.
As Dick Maury said, tow out would make the car vague in a straight line.
I presume that the steering rack bushings are also new ?
Yes, excessive pre-load will effect self centring as the rack and pinion will bind and not be able to move freely.
To test you could back the nut 1/4 turn and see if it makes any difference.
If everything else is in good in shape I too think that it’s a geometry issue.
I have yet to find a good and trustworthy alignment shop… the most common mistake they do is raise the car to put the machine on, but when it goes back down the rear does not settle and all the measurements are skewed.
The mid laden tools are very important, especially the rear.
How do you know if your car is a sportspack?
It’s a 1976 pre HE. The 572nd XJS manufactured. Way before any specials just a plain old common all garden XJS !
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