Well, the stickiness was your signal to replace the tumbler.Now you
have to begin the long and tedious process of replacing the whole
ignition...here are some instructions I copy and pasted from the
archives at mbcoupes.com
Removing the Ignition Tumbler when the key won't turn to "accessory"
position..... An alternative way avoiding brute force. (assuming
non-airbag equipped vehicles)
The ignition tumbler contains a spring loaded mechanism that locks
into the ignition lock housing AND the protective cover boss at the
time. This spring loaded lock can be released by inserting an
wire or pin into the hole in the face of the tumbler after having
key to the accessory position (middle mark on the black boss
In order to remove the tumbler, the black boss must be unscrewed from
ignition lock housing. Both the black boss ( the black "ring"
the tumbler is about 1-1/2 " long ) and the face of the tumber are made
The ignition lock housing is a "T" shape on its side, the long leg
steering lock plunger, the ignition tumbler on one end of the cross and
ignition switch on the other. The ignition switch (casting) is held to
ignition lock housing by three internal screws under the electrical
The electrical plug (plastic) cannot be unplugged (locked) except when
ignition switch is at the accessory position.
Also: the steering lock mounting pin holding the ignition lock housing
assembly to the streering column cannot be released until the steering
unlocked The steering cannot be unlocked until the ignition key is
at least to the accessory position.
Note: In the UNLIKELY event that the steering wheel has NOT been turned
engage the steering lock, TAKE EVERY PRECAUTION NOT TO TURN THE
WHEEL. If the steering lock is NOT engaged this procedure will be
- Remove the panel in the footwell under the steering wheel.
- Remove the instrument panel
- Remove the steering wheel. Try not to rely on the steering lock to
the wheel to undo the bolt.
- Unplug the cruise control harness and the turn signal harness. Facing
dash, these plugs are located at 9 o'clock behind the dash on a bracket
attached to the steering column. (One 5 pin, one 14 pin)
- Remove the cruise control/turn signal assembly (three Philips screws)
together with the plastic steering column shroud.
- The steering lock is visible once the steering column shroud is
The ignition lock housing (casting) is inserted into the tube (black)
steering column. From the instrument panel opening (or from under the
undo the clamp holding the two together and slide it aside. The round
locking pin (4mm) of the ignition housing arm is facing outwards from
dash in the black tube. IF the steering column is not locked, depress
spring loaded 4mm pin and push the ignition assembly away from the
- If the steering lock is engaged, the pin can not be depressed. With a
small grinding tool, (drill flex shaft tool or Dremel tool and steel
grind off the top of the 4mm pin. Once clearing the inside of the black
tube, push the ignition assembly from the tube. The ignition assembly
be free to rotate somewhat while shifting the assembly from the
lock tube. It may be helpful to increase clearance by loosening the
steering column mounting bolts.
-Once the assembly is free from the steering column, drop the ignition
assembly downwards below the dash. The assembly will be still attached
the ignition wiring harness. Some later ignition assemblies will allow
electrical connection to be unplugged. The original ones were locked in
place, again requiring the ignition tumbler to be at the accessory
If the wiring plug cannot be pulled off, do not force it. Break the
of the ignition lock housing at the three screw tabs holding the
switch. (use a hammer, small air chisel, etc) Once the ignition switch
separated from the holder, the switch can be turned to the accessory
position (trial and error) and separate the electrical plug from the
Care should be given to NOT damage the electrical plug for the ignition
switch. Everything else is easily replaceable. The ignition switch
can likely be salvaged if breaking the casting was limited to the body
the ignition lock housing.
To reassemble, new parts required will include: Ignition Lock Housing,
Ignition Tumbler (with keys), Ignition Switch (if damaged), Ignition
Locking Boss. (This last item could be salvaged once on the bench, by
smashing the old ignition tumbler from the housing casting.)
Reassembly is the opposite of disasembly. Install the new ignition