Adwest Marles power steering box.

[Glyn Ruck]

Yes there are inaccuracies. Many from Andrew Whyte ~ Jaguar's historian. Taylor's latest book has corrected many errors that were in the S Type & 420 book but there are still mistakes. I would love to rewrite his section on the SA CKD S Types. I think that Jaguar on many occasions just used what they had stock of. They even changed diff ratios due to supply issues from Salisbury.

BTW ~ Your PS fluid does not look too bad other than no longer being clear & bright. To check if that hazyness is in fact water is as easy as a simple crackle test. Take a teaspoon of fluid & heat it with a cigarette lighter. If it crackles it's water. Dropping a little fluid on a hot solid stove plate will do the same thing. Put a few drops of fluid on a hot stove plate. If it crackles it's water.

[cass3958]

Good tip Glyn but I think as I have cleaned the box of all the old fluid and I think the fluid is contaminated with sparkles of metal it is all being replaced with new. What would you recommend. I have ordered some Mannol 8980 PSF Fluid/Power Steering Fluid which is rated as MB 236.3 for Mercedes. I did this after your recommendation to get an MB rated oil for the engine and this was the only one I could find with an MB rating.

[cass3958]

Today the Adwest Marles PAS box went back in. Again do not believe what the manual says there is a lot more work involved.
First the box is offered up in to the cut out section on the cross member which you can see in this photo. You can also see there are four bolt holes on the cross member but there are only three bolts holding the Adwest box in place. The fourth hole, top left, is for when the previous Burman box was fitted to the S Type but they are using the same crossmember for this Adwest box. Sorry this picture is upside down but for some reason it will not let me set the orientation correctly.

Indent in cross member and four bolt holes..JPG (3.34 MiB) Viewed 2226 times

The steering box cannot be feed into position with the lower steering column attached or the drop arm unless you want to remove both the anti roll bar and the oil filter. You will note in my case I have changed my original oil filter to a spinoff system which is actually smaller than the original.

Showing lack of space between engine, oil filter and chassis leg..JPG (2.31 MiB) Viewed 2226 times

Once the steering box is in place (be careful as it is very heavy) tighten the three bolts to secure it in place. Next attach the hydraulic pipes to the steering box and the feed pipe and secure these to the cross member. Attach the drop arm getting the orientation correct using the previously mentioned punch holes I made as a reference and cinch the nut up. Next I attached the steering arms, this was so I could check the dead ahead position of the steering box to the dead ahead position of the wheels. I found that trying to tighten up both the tie rod nuts was difficult as they have a locknut and as soon as the nylon part of the locknut hit the thread the tie rod started to rotate and would not tighten. On modern cars you find they have got over this by having an Allen key hex in the centre of the bolt into which you can insert an Allen key to stop the rotation. Not thought of in the 1960s so it was a problem. I got around this by taking my angle grinder with a 1mm cutting disc and I cut a groove in the end of the bolt. I was now able to use a ring spanner on the nut whilst holding the bolt still with a screw driver.

Locknut on tie rod.JPG (1.68 MiB) Viewed 2226 times

1mm groove cut in tie rod bolt.JPG (2.48 MiB) Viewed 2226 times

screw driver and spanner on tie rod bolt..JPG (2.02 MiB) Viewed 2226 times

With the tie rods tight I checked the orientation of the front wheels in relation to the centering of the steering box and all was well. The lower steering column was ready to be offered up but before doing so I removed the pinch bolts and used a screw driver and hammer to open up the gap in the splines so the ends would slide more easily over the upper steering column and the steering box splines. The area you are working in is very restricted so having the splines slide over one another is esential. The lower column was then feed through the small gap between the oil filter and bulkhead and slid on to the steering box splines making sure that the splines matched up so the pinch bolt could slide in to place. The lower column has two U/Js and the orientation of the lower column is that the small end sits on the steering box whilst the larger round end with the rubber gaiter goes at the top and connects to the upper steering column. With the lower steering column connected to the box I had to use the Jaguar special tool called “ WIFE” to sit in the driver’s seat and to hold the steering wheel straight. When asked the “WIFE” pushed the upper column down to slide the splines together whilst I lay under the car and directed them in to place. Again emphasis must be placed on getting the splines lined up so the pinch bolt slides in to its groove correctly. Once satisfied that the system was all aligned correctly I tightened the pinch bolts then reattached the upper steering column to the underside of the dash and the bulkhead plate. Finally I checked all the nuts and bolts were tight under the car and ran a test by turning the steering wheel from lock to lock.
Because of the lockdown I could not pop down to our local car parts store to buy some new steering fluid so I have ordered some online and it is due to arrive either tomorrow or Friday so I cannot check the system for leaks until this arrives and I am able to refill the system.

[Glyn Ruck]

Good tip Glyn but I think as I have cleaned the box of all the old fluid and I think the fluid is contaminated with sparkles of metal it is all being replaced with new. What would you recommend. I have ordered some Mannol 8980 PSF Fluid/Power Steering Fluid which is rated as MB 236.3 for Mercedes. I did this after your recommendation to get an MB rated oil for the engine and this was the only one I could find with an MB rating.

MB 236.3 is absolutely perfect for the job. Excellent wear protection. Correct viscosity. Also Type F & G fluids meeting Ford M2C33F or G are ideal for long life of our steering systems.

Presume you are changing the filter.

[johngosnell]

Fantastic write up congratulations.


John

[cass3958]

Thanks for the confirmation on the right PAS fluid Glyn.

Presume you are changing the filter.

New filter on order from SNG part number 7752 which should also arrive today.

John I have not had any experience with the older Burman system so cannot compare the two for feel but the way the Adwest Variomatic works is on a worm drive but to make it easier to explain imagine it is a set of teeth in a row. The teeth at the centre are closer together so any movement with the steering wheel gets an instant response. The teeth towards the outside are further apart so the movement of the steering wheel causes less movement of the wheels. In the Adwest this set of teeth are a spherical worm shaft so the thread in the centre is closer together than the outer thread. What this achieves is when driving in a straight line the steering should be stiffer but immediately responsive but the more you turn the steering wheel the less responsive but easier it is to turn.

I do not think there is supposed to be any vagueness in the system but the fact it is more responsive in a straight line might give that effect if there is any wear in the box and you are constantly trying to correct the wandering of the steering in a straight line. Any small movement of the steering wheel at the dead ahead position is an instant movement of the road wheels but if all you are doing is taking up the slack it might feel vague.

On the Adwest steering box there are two methods of adjustment. Bearing in mind most of the steering boxes in our cars are now over 50 years old and possibly never been serviced in their lives, so will have a little play in them. The first adjuster on the Adwest is on top of the aluminium top cover and is a lock nut over a threaded bolt with a slot cut in it. The threaded bolt is attached to the Sector shaft and adjusts its connection with the worm drive. By undoing the lock nut and screwing down the slotted thread into the aluminium top cover you are making the sector shaft which has a metal wheel about the size of a roller skate wheel move down into the worm drive getting rid of any sideways movement caused by wear over the years of use. Too tight and it will affect the self centering of the steering wheel. Too loose and there will be movement between the two parts causing a vagueness or wandering in the steering. The blue book talks about 4 ft lbs of torque but how you attach a torque wrench to a screw head is beyond me so I did it by the other method suggested which is "By feel". This adjustment can be made whilst the steering box is in situ.

The second adjustment is between the three teeth on the sector shaft and the three teeth on the rack which is moved by the PAS piston. On the side of the box there is a large plug with a cross head screwdriver groove in it. This plug is held secure by a small Allen key grub screw. Under the plug there is a dome shaped metal friction pad which is used to push the teeth of the rack tighter against the teeth of the sector drive shaft eliminating any gap caused by wear. By screwing this plug screw down you can "feel" the slackness being taken up. Over tighten and you will feel the steering going tight so again by feel you can get the correct balance. This adjustment cannot be made with the box in situ as the plug is down the side of the box, between the box and the sump and you cannot access it in situ.

Adwest Marles Varamatic (2).jpg (126.86 KiB) Viewed 2202 times

Details of both these adjustments can be found on page 203 of the Jaguar 420 workshop manual which I am hoping David will add to the S Type Maintenance documents above soon as the S Type workshop manual only covers the Burman types 1 and 2 PAS system. There is an adjustment that can be made to the Burman box but it involves using shims and can be found on page I.39 of the S Type workshop Manual.

[johngosnell]

Thanks Rob , thanks for the detailed info after spending around £900 on replacing ball joints and poly bushes, springs and shocks with no great improvement I think what you have described is the way to go. There seems to be about an1"inch to 1 1/2"" of play when moving the steering wheel before the wheel's react. The other issue was until last week I did not know what box was fitted ,the work you have done has been very helpful, well done


Regards John

1B1257BW

[cass3958]

One more thing you can have checked first John is the lower steering column U/Js.
The Lower steering column has two. The lower is a standard U/J with roller bearings. Mine have a fraction of movement but not enough to justify a change just yet. The upper U/J is different. It has a sort of ball and socket joint with some nylon balls and pads inside covered by a rubber gaiter. Mine was fine but if this is not greased up correctly and protected from water and dirt the nylon balls can wear then create a small amount of movement. Get someone to look under the bonnet at the lower steering column whilst you turn the steering wheel and see if there is any play in that upper joint.
To remove and replace the lower steering column you may as well remove the steering box and make those adjustments at the same time.
The problem with the S Types steering is that there are at least five or six points from the tie rods to steering ball joints, steering columns and steering box where you might have a slight movement due to a worn joint. Individually one slightly worn tie rod will not affect the steering that much but when you have five or six slightly worn items then suddenly you have quite a bit of movement. You have done the right thing in replacing what you have but now have to finish the job with the steering box.

[johngosnell]

Further investigation to be done. Quite frustrating as this is a great time to do this work but I am on the governments high at risk list with 12 weeks of isolation, but yes this will be checked out. As a matter of interest how much movement should I expect between the steering wheel and the road wheels

Regards John


1B1257BW

[cass3958]

As least as is possible would be better but that does not answer the question. I have not been able to test mine yet as I am still awaiting delivery of the fluid and filter but I would hope now everything is tight as soon as I turn the steering wheel the road wheels should turn.
You do not want any backlash, the manual calls it preload, by this I mean if you turn the steering wheel and the road wheels turn you would want to be able to turn the steering wheel the other way and for the road wheels to follow immediately. If there is any slack that is where you are going to be getting your wandering and vagueness from.