Article reproduced from TR Register Club Magazine - June 1999
TR SWITCHES the following advice was sent to a member by Rick Fletcher in response to a request for assistance on a Light Switch. It is too good not to be shared further afield Let there be light . Ed.
Gavin has passed your request on to me. I will do my best to help you out.
The plastic knob is not screwed on - it is held by a small detent spring which can be released by pressing it in using a small probe, screwdriver, nail end etc. It is only tiny and can be seen if you look up at the bottom of the knob.
The knob then slides off the shaft. This leaves you free to remove the chrome retaining nut (with care!).
The switch can be maneouvered out but it is much easier if you release the central instrument panel cluster. This should be held by 4 wingnuts which can be undone by finger - unless some galah has replaced them with nuts!
Note which wires come off where. The base of the switch is labeled S1 S2 and A to help you.
The switch is serviceable, depending on your ingenuity. It will certainly need a good clean - electronic cleaning solvent or similar. You can then see how the contacts work - very basic. The brass contacts will be filthy and oxidised but a narrow strip of wet & dry paper (very fine) will help.
The contactor "core" in the centre is held onto the shaft by a riveted setup at the end of the shaft - obvious from the bottom end of the switch. This may be loose. It MIGHT be possible to remove this "core" which would then give you great access to clean and refurbish. Otherwise gently tighten the rivet.
Take great care when you remove the small screw in the side of the body - in the bakelite, closest to the dash. It has a small SPRING and BALL BEARING inside which will disappear if you remove the grub screw carelessly. All this area needs cleaning. The spring and bearing provide tension on the shaft. All of this needs a microscopic amount of lubrication when you reassemble - also the main shaft.
Perhaps the brass contacts could be coated - a tiny amount of petroleum jelly - or perhaps they are best left dry - I'm not sure. Doing it would help prevent oxidation but it would then gather dust!
Because they are hard to get, it makes sense to repair and preserve them.
Hope this helps . Rick Fletcher