Hi All,
This is an area of the car where I consider the Lotus design is far from satisfactory.
In a nutshell, the steering column is a two piece affair with a clamp in the middle of it that allows the forward inner column to slide into the aft column tube on frontal impact. A clamp is used to allow this sliding action, while retaining the ability to steer the car.
The whole column assembly is mounted via the flexible joint at the steeringrack, then via a Triumph herald clamp to the top of the drivers footwell, and again via another clamp to a mounting bracket located near the dashboard. The mounting bracket is in turn mounted to the bulkhead.
i had several concerns with this set up in my Plus 2. The first is that the column does not follow a straight line between the rack and the mount closest to the steering wheel. The clamp into the top of the footwell was pulling the centre of the rack upwards, and this was putting unnecessary stress on the column. Lowering the column centre so that it ran straight meant that the studs in the clamp were no longer long enough to protrude through the footwell. The second concern was that the bulkhead and footwells were too thin and this resulted in excessive flexing in the whole assembly.
I solved this by mounting the column at the rack and by the clamp nearest the steering wheel, lengthening the lower clamp studs so that they would reach through the top of the footwell from a lower column position, and reinforcing then entire bulkhead with LOTS more glass. Finally, i replaced the rubber bushes in the upper column.
My column is now straight and almost rigid. This should eliminate unnecessary stress on the column. I could make the column rigidly mounted by strengthening the mounting bracket which flexes excessively, but thats a job foranother day.
Ray
-----Original Message-----
From: Sean Murray [mailto:***@***.***
Sent: Tuesday, 15 April 2003 06:44
To: ***@***.***
Subject: Re: [LotusElan.net] Steering Column
Hi Steve,
Have you had a good look at the fracture, is it a clean break or is there any evidence of a previous cracking which would indicate contributory fatigue failure.
The less-than -solid mounting of the short steering tube in the +2 does nothelp to avoid putting the shaft under stress at this point.
One reason I reinforced this area.
Sean Murray
----- Original Message -----
From: Steve Crook
To: ***@***.***
Sent: Monday, April 14, 2003 11:57 AM
Subject: [LotusElan.net] Steering Column
Has anyone had a similar failure to this?
An Elan+2S 130 was brought to me (on a trailer) with failed steering, on
examination it could be seen that the end of the top or steering wheel
section of the two piece shaft had sheared at the clamp which is fitted to
control the telescopic action required for crash protection ie the cut away
piece where the clamp fits down in the footwell. The shaft had snapped
completly off at the clamp, luckily when the car was being pushed (yes itis
a Lotus) my concern is has this occured to other cars and is this a failure
point?. The car had been involve in a minor accident to the right front and
while there was some body damage the wheel, a Lotus alloy, appears ok
although there are signs of slight damage to the tyre. Has anyone else had a
similar failure or can this be put down to the accident damage?
Steve Crook
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