bump steer confusion

PostPost by: mariodschy » Tue Apr 28, 2015 6:07 am

Yesterday i've measured the bump steer, first i take the lower wishbone bolts and second i tried the brian buckland (upper wishbone) methode.
First thought was positive because i got a difference of 3,9mm and the original shims difference were 3,75mm so it looks plausible and correct, but i could remember that the shims were on the other side. After checking the pictures from the disassembleing the confusion was perfekt because my memory were correcht and the shims were really on the wrong side.
The question is: could it be really possible that lotus measured the right needed shims high but put the shims on to the wrong side and no one of the former owners does reconize an exzensive bump steer in 78.000 miles.
I am not 100% sure but it looks that this was the first time ever that the steering rack was removed from the chassis.

Here's a drawing for better understanding
Attachments
bump steer.pdf
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- 1972 Lotus Elan Sprint LHD/DHC
- 1962 Austin Healey Sprite MK II - Sold 09.05.2016

Sorry for my bad survival English ;-)
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PostPost by: Mr.Gale » Tue Apr 28, 2015 10:06 pm

I went through adjusting my bump steer and also had a hard time understanding how to measure it. What I ended up doing was making a video (two parts) of my simple procedure that I sent to a friend to confirm that I was doing it correctly (I was). As you can see in the videos the laser beam is making an arc as the suspension goes up past level, I just added shims until the beam move straight up from level (the X) on each wheel.

Mr.Gale

https://www.youtube.com/watch?v=zOi9nDYre_A
https://www.youtube.com/watch?v=z72l1wGubNo
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PostPost by: ericbushby » Wed Apr 29, 2015 9:48 am

mariodschy,
It seems that anything is possible with Elans, either new or in the years since then.
Bump steer has been discussed many times and a search of the archives will be useful.
If you type 'bump steer yet again' into the search box at the top of this page you should get a discussion which I contributed to last year which worked well for me when I discovered that my car had no shims at all !!.
Basically it involves removing the spring, fixing a laser pen to the hub and with the chassis level move the suspension up and down watching the laser draw a sloping line on a piece of cardboard on the garage wall.
Adjust shims until the line is vertical.
Let us know how you get on,
Eric in Burnley
1967 S3SE DHC
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