Lotus 2004 Eleven Service Notes page 238

Lotus Service Notes
The upper steering column assembly comprises an inner column which connects the steering wheel to the
intermediate shaft, and a tubular steel outer column which, with its alloy upper bearing housing, supports the
inner column and carries the column lever switches for lighting and wiper control, and also the ignition switch/
steering lock.
Both inner and outer columns are of fixed length, but are telescopically collapsible when subjected to
crash forces. The two parts of the inner column are fixed together by plastic pins designed to shear and allow
telescoping to occur beyond a specified axial load. The two part outer column tube uses gripper rings to retain
the column length, with the lower part mounted by a single fixing to the chassis scuttle beam via a three point
fixing steel bracket. The upper part of the outer column has two open slotted mounting flanges each of which
is fitted with a 'break out' alloy insert, bolted through to an extruded alloy plinth fixed to the scuttle beam. In
the event of an extreme axial load being applied to the column via the steering wheel, as may occur during a
vehicle frontal collision, the plastic retaining pins in the column flange inserts will shear and allow the upper
part of the column to break free of the upper fixings and telescope forwards, reducing the potential for column
induced injury.
Column
lower
fixing
Chassis
scuttle
beam
Dimensional Check
If the vehicle is involved in an accident, or any part of the column is subjected to an abnormal load includ-
ing airbag deployment, the column should be carefully examined to establish if any telescoping has occurred.
Perform the following checks, and replace the complete upper column assembly if any of the dimensions are
outside specification:
1. Outer Column:
Measure the length of the lower part of the outer column as shown:
Specification = 80 ± 1mm
2. Inner Column lower:
Measure the length of the exposed part of the inner column as shown:
Specification = 58 ± 1mm
Page 6
Column slotted
flange
Section HG
'Break out'
insert
Column flange broken
out of insert
Normal
Condition
h50a
Collapsed
Condition
h51a