S Type steering conversion - by Alastair Reynolds

I Have been the owner of an S Type now for the last 3 years (9000 miles). When I got the car the steering was to be honest a bit flakey. I replaced the track rod ends (4 off) and the idler and spigot bushes. Jamie Gibbon in Glasgow shimmed the power box to something like normal. The steering was ok but not fantastic, not exactly positive but at least not dangerously vague like before. These renovations kept me going for two years but in a moment of madness in an attempt to replace a leaking steering pump with a second hand pump I test drove the result only to find that after a few miles the pressure limiting valve stuck and all power to the steering box was lost. The process of returning home with no hydraulic steering pressure was enough to completely stuff the free play in the box to an unacceptable level again.

Worse than that Jamie from Glasgow did not recommend shimming the box again in case the steering seized in extreme conditions of lock and temperature. I spent the winter of 95 looking for a second hand box in reasonable condition, this proved to be a fruitless task, the closest I came was the temporary purchase of a reconditioned box from FB components. This turned out to be the wrong type.

At this time I became more interested in the various conversion kits to modern rack and pinion. There are three kits on offer Ken Jenkins, Barratts and a company called Classic Jaguar Spares. The Barratts kit is manufactured by Vicarage. In fact Anthony Parkinson run's Vicarage's US marketing operation and is a very active participant on the Jaguar Lovers Internet mailing list. I have to state I did not want to do this conversion, I dearly wanted to keep the car original. If the cost of keeping the car original was really poor steering then that was a price to high. Either upgrade the steering or sell the car that was the choice. I decided to keep the car.

For almost one reason I chose to pursue the Barratts/ Vicarage approach, they were also the most responsive to my questions. The reason I was keen on the Vicarage kit was the treatment of the power assisted steering (PAS) pump, located below the generator away from the roasting manifolds and retaining the original fan belt and pulley system.

The down side is that they had never fitted the kit to an S Type. I looked closely at the manuals and the chassis of both cars, they looked very similar to me. Barratts (Richard Darcy) were very keen to sell me a kit but initially could not give me a guarantee that the kit would fit my S Type. As time passed I kept phoning Richard up asking if they had any more information about fitting their kit to an S Type. He eventually came up with an offer I could not refuse (I guess he figured it was the lessor of two evils, lets face it I was not for giving in). They would sell me a kit and if I had any problems they would fix them no matter what the problems were. They would even fit the kit for free if I took the car to them in Shropshire, if I chose to fit it myself then if I got stuck then if I got the car to them they would still fit the kit for free assuming I had not caused any damage in the process.

Being a Jag enthusiast of course I was not keen to let someone else have the fun of converting my S Type for me. I elected to buy the kit and fit it myself despite the kind offers of Barratts. Armed with the assurances from Barratts the distributors and Vicarage the manufacturers I proceeded carefully.

The kit arrived in two days, that is where the fun began (I do not mean that in a negative sense), the rack fitted well enough, some minor tolerance problems with the left mounting bracket (bolt alignment) I suspect the Jag chassis was not manufactured to the same tight tolerance as the Vicarage bracket, some obround holes would be helpful. The main problem is with the clearance between the knuckle joint connecting the lower steering column to the new rack and the chassis. The lip on the corner of the chassis fouls the new joint (see photo). I was being sent by my employers on a business trip on the 1st April 96 to Vancouver, so I arranged for Alistair Buxton from Thorns Garage to modify the chassis, I was not happy with just bending the lip up, as recommended on the MK2 conversion.

On my Return from Vancouver I found the welding had indeed been done (see photo), Alistair had left plenty of room for the new steering joint, he had even reconnected the lower column for me. The next step was to connect the pump, no it did not fit, even although the chassis dimensions according to the Service Manuals look identical at the front between the MK2 and S Type. I wrote an e-mail to Anthony Parkinson in the US and he said to contact Malclom at the factory in England. Malcolm was extremely helpful, and extended the offer again to bring the car to him and he would fix the problems.

I do not give up that easily, there were two basic problems, 1) The engine stabiliser brackets on the sub-frame denied access to the rear of the PAS pump for the hydraulic pipes. 2) The PAS pump fouled the engine mounting in a major way so as not to be adjustable for it's drive belt.

I tackled the stabiliser bracket by removal, as the bracket by 1966 was no longer used. This unfortunately required the removal of the sub-frame first.

The other problem required a new bracket. I phoned Malcolm again with a new suggestion, how about me sending him a design for a new bracket and they could make it up. To my surprise

Malcolm said yes, I sketched a quick drawing and FAXed it to them for comment. To my surprise they proceeded to make the part. In the interim I found another problem with the conversion. Vicarage designed their kit to integrate the lower engine mounting and the PAS pump into one bracket. The MK2 conversion remounts the Generator (if not already mounted) on a separate bracket (not supplied 15 pounds) fixed above the engine mounting. The original S Type bracket has the engine mounting and Generator mounting integrated.

I phoned Malcolm at the factory and explained the new problems, as ever he could not have been more helpful he put me in touch with Peter who was making my bracket. I agreed to send a new set of drawings after I modelled the new set up in foam board so as to get some check on my design. Foam board is one of these modern materials that professional model makers use for fabricating look-a-like models of the finished product. I choose some 3/16 thick the same as the mounting bracket for the steering pump. After three attempts I eventually had a design that worked, the foam board is so strong you could even mount the pump in it's new position and check the clearances. The bracket design (including Generator mounting now integrated) was FAXed to Malcolm on the following Monday and to my utter astonishment the bracket was ready by Tuesday afternoon. This buy the way is no ordinary bracket. For a start it is made of 3/16 inch mild steel with no fewer than 12 parts before welding. The parts themselves were not a simple shape either. Those chaps at Vicarage certainly appear to know what they are about. Malcolm said ``he had never seen a bracket like it, mountings for everything in all directions''.

The bracket is now fitted it is as designed the best compromise in all directions. Best clearance between PAS pump and chassis, best clearance between pump and engine mounting, best clearance between return pipe and sub frame.

Conclusion

My steering is now a miracle of modern engineering, I have driven it aggressively and I can honestly say there is no hint of bump steer problems so as I can detect. To be honest that was my biggest worry. I checked the steering geometry on axle stands (off load) and on the ramp ( on load) the geometry as far as I could tell remained the same. That is measuring the tracking in both positions I think I would have detected if there was a problem. I guess there could be a problem with the geometry while cornering, but aggressive driving so far has revealed no nasty behaviour.

I enjoyed the problem solving, especially when I now know the people at Vicarage who have renewed my faith in classic car business. It is nice to talk to people who are interested in your problems after they have collected your money. Vicarage does now have a solution for the S Type and my testimonial as to their organisation.

I can show by this article that you can with some effort and very little skill fit modern steering properly to an S Type with good backup from a professional organisation. If I was to do the job again I am sure it would take half the time. After all my estimates include time to design a new bracket, that was the only skilled part of the job.

Health Check

1. Loosen steering column so as to release lower steering column.
2. Disconnect old steering hardware
3. Mount new steering rack ( 4 bolts).
4. Remove carburetters for access to chassis for welding. You can do this without removing the carbs if you have a pit or a ramp.
5. Modify chassis (see photograph) to allow plenty of room for knuckle joint at bottom of lower steering column.
6. Remove radiator to gain access to engine pulley.
7. Remove Generator and bottom engine pulley.
8. Fit new bottom engine pulley
9. Remove sub frame and steering to grind off stabiliser bracket. Remove bracket. (MK2 does not have this bracket).
10. Refit subframe
11. Remove right hand engine mounting
12. Fit mounting bracket for Generator, PAS pump and engine mounting removed in 8.
13. Refit all the hardware that is not already replaced (e.g. Carburetters, radiator, Generator etc.).
14. Set up steering geometry, any good service manual with rack and pinion steering will tell you how to do this.

Note:- When considering the cost of this upgrade remember all the parts you come across that may need replacing because they are old or worn out

Alastair Reynolds 1996