steering rack shims...a query from 1994

[milton]

I have a new/old stock Lotus galvanised chassis for an Elan dated 25 July '94! There is information scratched on the front cross member which I guess refers to the shimming for the steering rack. It appears to be LR 2043. Anyone familiar with a chassis from this period, could you confirm 0.020" left and 0.043" right?

[ericbushby]

I suspect it means `Lotus Replacement` chassis (LR) with serial number 2043
Hope this helps
Eric in Burnley
1967 S3SE DHC

[661]

Sorry , I don't think you can rely on 'similar' chassis'.
I think you should have the bump steer set for your chassis.

[StressCraxx]

Sorry , I don't think you can rely on 'similar' chassis'.
I think you should have the bump steer set for your chassis.

Graeme is exactly right. The manufacturing tolerances available on the chassis, rack, uprights, required using shims to set bump steer. Years of abuse, replacement parts and corrosion require properly setting bump steer again.

With the shim numbers for my chassis we found 1/16" toe out on the left and almost 1/8" toe in on the right. With the right shims, my bumpsteer is less than 0.006" toe in per side.

[nmauduit]

I suspect it means `Lotus Replacement` chassis (LR) with serial number 2043
Hope this helps
Eric in Burnley
1967 S3SE DHC

I'm pretty sure that is indeed the meaning of LRxxxx : a Lotus Replacement chassis number (and not a shim value).

[Donels]

Yep that's the Lotus Replacement chassis number. I have LR 1141 which is around 1986, Tim will be along in a while and tell you when it was made.

To find the shim dimensions use the Brian Buckland method. Put a straight edge on top of the front wishbone spindles then measure down to the rack mounting positions. The rack needs to be at 158 mm from the spindles, so the difference is the shim thickness required.

[661]

Or do it yourself....
You can't use the Buckland method if you are using TTR 26R front suspension as the steering arms are bent away from the discs.

[MACCA.GLM]

Hi Donels

Does this apply to the spider chassis as well

G

[Hawksfield]

Hi iam interested in the Buckland method of rack mounting shim sizes.
Is there a drawing of the method, can it be done with body on.

Thanks in anticipation.
John

[Donels]

According to Brian this figure applies to the Elan, +2 and spider chassis.

John,
I don’t see how you can get a straight edge across the spindles with the body on. I’m away from home at present but when home I’ll attach the picture from Brian’s book.

Dave

[661]

According to Brian this figure applies to the Elan, +2 and spider chassis.

John,
I don’t see how you can get a straight edge across the spindles with the body on. I’m away from home at present but when home I’ll attach the picture from Brian’s book.

Dave

Perhaps buying the book would be a prudent move........

[Donels]

Here is the relevant bit from Brian's book.

I think I bought the last book from Brian and I don't think he would mind me publishing this bit of info for the good of the Elan community. Brian is a very helpful person and happy to share info without saying "Buy my book".

[Hawksfield]

Donels
Thanks for the the information,just a point of interest.
I did a body off refurbishment on my car in 1987 and refitted the shims I took out, at time I could not find the etchings on the chassis to check. But as it was the original chassis there was no problem.

661
As I have had this car since 1986 and ran it successfully I don't think its prudent I spend on the book.
Thanks for your comments

[Donels]

Hi John,
I bought mine as a restoration project. It had been fitted with a Lotus Replacement chassis when I got it. On investigation it looks like it had had a right front chassis leg failure at some point, hence the LR. The rack had been mounted on 6 mm thick shims (shims? No they were plates) and using Brian’s method I actually needed 1 mm and 2 mm shims. The bump steer must have been interesting.

Dave

[Hawksfield]

Dave
I have lost the record of the shims sizes fitted to my chassis.
On recollection there was two shims each side and they were about 2 mm in total. If ever lift the rack I will record the sizes for my cars history. I have learnt a lot since I first got this car and enjoyed the project but to old now to start another, so I read this forum with interest just about every day.

Thanks for your interest
John