The Electrical System

The Ruston 48DS has a very simple electrical system consisting of a 12 volt battery, front and rear facing spotlights, a cab light, a horn, a dynamo and a starter motor.  The Control Box in the cab has 4 pull switches for the lights and starter, a keyswitch, a dynamo warning light and a 2-pin socket for an inspection lamp.  Needless to say all of this was in a very poor condition.

Some of the electrical parts, including a very corroded control box

 Everything was wired up with brass-bound armoured cable.

The armoured cable, along with one of the horn push-buttons

Unfortunately, the rubber insulation had perished creating short-circuits and was unusable.  New armoured cable is available from suppliers of parts for classic car restoration.  Replacement cable bound with Aluminium would cost about £100, and brass-bound cable approximately twice that.

 

Inside view of the rebuilt CB

An "R" needs to be engraved on the second button (Front, Rear, Cab lights and Start)

A new Control Box was made from steel sheet, silver-soldered and painted.  The design was altered so that the front panel could be removed without the whole box becoming loose (hence the brass pillars).  Ruston made good use of Lucas parts in their electrical systems.  Fortunately when Lucas CAV closed down, much of the tooling was bought up and many old parts are still available (although made with modern plastics rather than Bakelite).  The new parts are the fuse holder, the junction box, the keyswitch and the 2-pin plug and socket.  The pull switches were repaired by cleaning up the contacts, but new knobs had to be bought to replace the missing originals.

The front and rear lights, the cab light and a new horn push-button

The spotlight on the left is an original that has had corrosion repairs and has been refurbished.  The light on the right was from a tractor, and has also been refurbished.  The other original spotlight was too corroded to be repairable.

The cab light glass was smashed.  However a clear glass lens of almost the correct size was used in Minis and other BLMC cars, and was still available.  Its diameter was slightly less, so a new retaining ring was machined in EN316 stainless steel with a very fine thread so that it screwed onto the original fitting.

There are two horn buttons, one on each side of the cab, but neither was serviceable.  Again, new identical Lucas parts are still available and one of the new push-buttons is shown alongside its box.

The horn with its new cover

It says "CLEAR HOOTERS".  It isn't particularly loud, but you'll have plenty of time to get out the way.

The horn had a cover to keep out the rain, but it was crudely made from thin steel sheet.  A more robust cover was made from a section of steel pipe.

The refurbished dynamo

The dynamo was made by CAV and originally had a CAV regulator fitted.  However this must have been replaced while at the distillery with the familiar Lucas type fitted to many cars of the 1960s.  It still uses the original mounting bracket.  The dynamo seems to be in good order and only needed cleaning and new wiring.

The refurbished Oil Pressure Gauge

This isn't an electrical component, but it is part of the instrumentation (the only instrument, in fact).  Apart from cleaning up, a new pointer had to be made and a new glass fitted (after at least 3 attempts at cutting a circular piece of 2mm glass).

The starter motor only needed cleaning and rewiring.  The starter solenoid was missing, so an old Lucas one was used and mounted on the starter.

One of the last stages in the project will be to fit all this equipment, but that is some way off.  We still need to buy some of the original type of wire-bound armoured cable before then though.