THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

If I was to put a smaller diameter steering wheel on the car would it stiffen up the steering. I had all the front suspension rebuilt last year to help but it is still as light as ever having a non variamatic power steering system. It can be really hard trying to keep a strait line with one hand .


John

1B1257BW

First you should check if you have correct castor setting since that effects most the steering to return to straight ahead direction. If it is less then that specified you could experience a wondering effect. Could it be that shims got misplaced when you rebuild your suspension? Theoretically a smaller steering wheel needs more effort to turn albeit most probably it would not be noticed because of the power assistance. Still, it should not effect feeling and response.

The S Type runs so little castor (close to zero) that it won't make any difference to self centering. You need castor in the 9 to 10 degree range for that. Like the Germans use for their autobahn cruisers. Nice high speed stability. Our S Types run virtually no castor & camber to try & keep steering light with manual boxes. Only later did Jaguar design into their front suspensions considerations like anti dive & adequate castor/camber for road holding.

A smaller wheel would require a little more pull at the rim but I don't think it will have the desired effect.

You can try to dial in a little more castor than Jag recommend but there is not much adjustment. People that modify/race these cars also dial in about 1.5 degrees negative camber

All that might help is modifying the the pump pressure release valve to drop pressure but it would be trial & error.

Wheel alignment:

Standard Castor = 0 deg +- 1/2 deg
Standard Camber = Positvie 1/2 degree +- 1/2 deg.
Toe in max 1/8th inch.

Unfortunately for you John the PAS on the S Type is from the 60s and was designed to allow this big heavy car to be maneuvered at low speeds. Unlike modern cars that have progressive PAS where the steering becomes heavier the faster you go, our S Types steering is as light at 100 mph as it is at 5 mph. It is something I was not comfortable with at first but have grown used to overtime.

Because on the Isle of Wight roads are like in Devon and Cornwall We have only one duel carriage and is about 1 mile long the remainder of the island are basically a one car lane for either direction and very bendy So driving at high speed or on country lanes with one hand is very hard.

John

1B1257BW

Although the PAS system feels woolie it is a lot better in your case to have it than not. I would not like to drive an S Type without PAS one handed especially trying to park.

Agreed !!!!!, our Rover does not have PAS and yes it is very hard, but driving is better being more positive.


John

It will cost but you can remove the old hydraulic PAS and have a modern electric conversion fitted which will give you a more precise feel at speeds but the lightness when parking. My mate considered it for his Alvis until he saw the price! It a lot more than five years of gym membership.

Rob, You are a good person to ask this question as you have suffered partial star drive failure to your PS pump. You said you picked this up by steering being heavier than usual. This means the pump was giving less than it's approx 1000psi. At lower pump pressure & with heavier steering was the car any better to drive at speed?

If only one could apply large castor angles to these cars it would make a huge difference. Even the XJ6 started moving in the right direction with 2.25 deg positive castor.

At lower pump pressure & with heavier steering was the car any better to drive at speed?

Hard to say Glyn as I noticed the failure of the pump at low speeds and swapped it out for my spare pump before I drove the car any further. Although the star drive had failed when I took it apart and I thought this was the problem I made my own drivers and fitted them and found it was the pump that had failed not just the star drive. Changing the pumps over fixed the problem and I have just found a Holbourne Eaton seal repair kit in my box of many parts so might have a go at repairing my old original pump as this is the one that has the holes on the back to fit the heat shield. If not I think I will send this one off to have it refurbished but at the moment do not know where to send it. Any suggestions would be appreciated.