LR3/Disco 3
The column lock comprises a cast housing which contains the locking components. The unit is assembled and sealed
with a cover which is secured with roll pins into blind holes. The column lock is not a serviceable part and must be
replaced as a complete component. The lock has a locking bolt which moves up and down on a cam. The cam is part of a
shaft which runs through the lock and is operated by rotation of the ignition key in the ignition barrel.
The column lock is attached to the column with two shear bolts. When the column lock is fitted to the column, the bolts are
tightened to a specified torque which shears off the heads of the bolts, preventing easy removal of the column lock.
The ignition barrel is fitted to the right hand end of the column lock. The lock is pushed into the bore and locks in position.
Removal and fitment of the barrel is achieved by inserting the ignition key into the key barrel and turning to position I. To
remove from the column lock, a suitable probe must be inserted through the release hole to depress the locking plunger
on the key barrel. The key barrel can them be pulled from the lock using the key.
The ignition switch is fitted to the left hand end of the column lock. The ignition switch is pushed into the bore and two
plastic clips locate in slots in the lock to retain the switch. Removal of the ignition switch is achieved by ensuring that the
key is in the ignition barrel and turned to position I, depressing the two plastic clips and pulling the switch from the lock.
Before replacing the ignition barrel, ensure that the switch is in position I (a new switch is supplied in position 0), and
ensure that the drive tangs on the lock shaft are aligned with the alignment mark on the lock casting. Push the switch into
the lock and ensure that it is fully engaged on the drive tangs and the plastic clips are fully located in the slots.
CAUTION : Before removing the ignition switch and/or key barrel, ensure the lock is in key position I.
Ensure that the shaft is not rotated from this position, when the ignition switch has been removed from the
column lock. If the shaft is rotated, a plunger and spring can become unseated in the lock bolt mechanism
causing incorrect operation of the column lock. It may be possible to detect this condition by shaking the lock,
as the plunger and spring may be heard moving around in the lock. In this condition the lock is not serviceable
and must discarded.
