Marles varamatic steering box

[Robbo911]

Hi All.

I've owned my S type for roughly 5 years but only now getting around to making it roadworthy. My plan is to fix the major issues and run it for a while. Ultimately it will need new paint but I'd like to sort out the running gear and run it for a while before that major step.

It has the Burman PS box as standard, but it leaks (as does a spare box I have) despite new seals. So I have managed to locate a reconditioned Marles box from Ken Jenkins which I am hoping, based on what I have read, will give me better feel and fewer turns lock to lock. I am planning to swap the box over the near future but have a couple of questions I am hoping you can help me with:

1. Looking at the 420 manual, the centre tie rod should be set at a fixed length of 16 and 7/16 inches and toe in set by the track rod ends leaving the centre at the fixed length. My question is where is this 16 and 7/16 inch measurement made - is it between the centre of the pivots or somewhere else?

2. I am planning to use my existing subframe which has the indent for the Burman PS box. I am assuming/hoping that the Marles box will bolt straight in but would be grateful if anyone can confirm?

Many thanks

[cass3958]

Not sure where the measurement is taken from but Glyn might be able to help there.
The Adwest should fit in the indent which was there for all the PAS steering boxes. Mine is held in with three bolts but I think there are four bolts in the subframe for the Burman box.
The Adwest had a beefed up drop arm (which was curved rather than straight) and tie rods and it is important to have these on the car. They were beefed up to prevent them bending if you turned against a kerb with the lower ratio power steering. If you have the full set up from Ken then it should not be a problem.
If you are talking to Ken Jenkins I assume you are in the UK but can you update your profile, top right, with your location please or put it in your signature block.

[Robbo911]

Thanks for the confirmation on the subframe indent and the information on the tie rods/drop arm. I should have the right bits - although I didn't get the tie rods etc from Ken (just the box and drop arm), they came from a 420 and Ken has run his eye over them.

I struggled to find where to put my location info but have now found it.

If Glyn (or anyone else) knows the answer to the measurement question that would be great.

Thanks again.

[Glyn Ruck]

Later cars had a fixed length centre tie rod without removable ball joints.

Your car obviously has the tube that you screw the tie rod ends into equally. The measurement is from centre of ball joint to centre of ball joint. The tube itself is fixed length. With Varamatic steering toe is set with the outer tie rods. The exact opposite of all previous models where toe was set on centre tie rod with fixed outer tie rods. This is to maintain centre of the variable curve that the Varamatic operates on.

Burman boxes had no indent in the subframe so it sounds as though you already have a Varamatic Subframe. See example below.

Varamatic centre tube..png (49.38 KiB) Viewed 1312 times

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8699808.jpg (45.16 KiB) Viewed 1310 times

[Robbo911]

Thanks Glyn. You are right, I have the tube arrangement into which the joints are screwed. Centre of the ball joint to centre of the ball joint makes sense for the measurement, the car from which the parts came must have already been tampered with as the measurement centre to centre was different from the required length.

I am somewhat confused about the subframe I have, based on what you say. Currently fitted is the Burman PAS box (which I have swapped a couple of times for my spare one) and I'm pretty sure it has the indent, but I may be mistaken. I will need to check when I next get the car in the air.

Thanks again

[cass3958]

I have the Marles Adwest so I am just guessing here but think I am right. Both the Adwest and Burman PAS steering boxes required the indent in the subframe but the standard non PAS Burman steering box did not require it. We have had a lot of enquiries about how to change from a standard box to a PAS box which does require altering or changing the subframe but as you already have the PAS set up the indent should be there. The only difference as I understand it is that the Adwest only uses three of the bolt holes in the subframe where as the Burman PAS unit used four.

[Robbo911]

That sounds right as regards the indent, hopefully it is as I am at this stage hoping to avoid swapping out the subframe. I'll confirm when I get a chance to take a look.
Thanks

[Glyn Ruck]

No. The Burman PAS boxes don't have the indent. My car has the 2nd type Burman and no indent. Why Orlando had to do this to fit the Varamatic.

orlando cross member.JPG (1.49 MiB) Viewed 1291 times

[Robbo911]

I am covered either way as I can lay my hands on a varamatic subframe if I don't already have the one with an indent on my car but if I am going to go down that route I should renew all the bushes etc which I was hoping to avoid at this stage...

I should have time at the weekend to check out what subframe I do have. I'll let you know

Thanks

[Glyn Ruck]

That's good to hear so you are covered.

Replace these X 2 with the uprated Teflon variety. The standard ones are a curse & WILL fail or probably have already. Part Number 133101U ~ The rest you can do as it suits you when you have time if you have a bush puller.

Tie rod pin & bush.JPG (23.38 KiB) Viewed 1275 times