Lotus Evora, Service Notes

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Page 9
Lotus Service Notes Section HI
HI.5 - STEERING COLUMN ASSEMBLY
The steering column assembly includes a two-piece upper inner column, consisting of two tubes ('A' up-
per; 'B' lower) with a sliding splined joint to accommodate reach adjustment, articulated via a universal joint
to a similarly constructed two-piece ('C' upper; 'D' lower) intermediate column, which allows for telescoping
compression in the event of vehicle collision. A third, lower column ('E'), is articulated from the intermediate
shaft via a second universal joint, and is splined directly to the rack pinion shaft.
The upper column assembly comprises a steel mounting bracket from which is hung a pivoted alloy car-
rier for the ball bearing race supporting the lower end (B) of the two-piece upper column. The upper (steering
wheel) end of the column (A) is supported in a steel tube outer column fitted with synthetic plain bushes. The
outer column is fixed to the column mounting bracket via a cam operated clamp, which allows vertical and axial
movement of the upper outer/inner column assembly, the inner column (A) being free to slide over the splines
on the lower column (B). The upper end of the assembly incorporates an alloy housing to accommodate the
steering lock/ignition switch and top bearing.
The lower end of the upper column assembly is articulated via a universal joint to the intermediate column,
which itself comprises an upper tube (C) splined over a lower shaft (D) to provide a telescopic length variation
of approx. 50mm. This feature allows for steering column length compression in the event of vehicle collision
in order to reduce the potential for occupant injury. For a similar purpose, the mounting bracket for the upper
column assembly is constructed in two parts, the forward part being rigidly secured to the scuttle beam, whereas
the rearward part is retained to the beam only by open ended slots equipped with special 'break out' inserts.
In the event of a heavy forward load being applied to the steering wheel, such as may occur in an accident,
the rearward part of the bracket complete with upper column assembly is able to break free from the scuttle,
pushing the column (B) through the lower bearing and collapsing the intermediate column. After any such oc-
curence, the complete steering column assembly should be replaced.
If, in any circumstances, an abnormal load is applied to the steering wheel or upper column assembly,
the column shrouds should be removed and the 'break out' inserts carefully checked.
To Remove Steering Column Assembly
WARNING: The driver's airbag is housed in the hub of the steering wheel. Precautions need to be
taken for personal safety when working with airbags and associated componentry. Do not attempt to
remove the airbag, steering wheel or column without first referring to section WF.
1. Remove the steering wheel (see sub-section HI.4).
2. Remove the rotary connector (see sub-section WF.10).
3. Remove the fascia dash panel (see sub-section VE.7).
4. Release all wiring harness restraints from the column.
5. If necessary, remove the steering lock/ignition key barrel: Turn the key to position 'I', depress the spring
pin accessible via a hole in the rear of the housing, and withdraw the lock barrel.
CAUTION: Once the lock barrel has been removed from the column, it is essential NOT to turn the lock
mechanism. Failure to heed this advice will result in the mechanism being irrepairably displaced, and
a complete new column assembly being required.
When re-fitting a lock barrel, note that the key must be positioned at '1' before the locating pin may be
depressed to allow insertion. Ensure the pin is correctly engaged in the housing hole.
6. If necessary, remove the ignition switch: Depress the two retaining barbs, and withdraw. When re-fitting,
the position of the ignition switch must be adjusted to match that of the lock spindle.
CAUTION: If the lock barrel is removed, on no account should the position of the lock mechanism be
disturbed, or irrepairable displacement of the mechanism may occur, necessitating replacement of the
complete column assembly.