Reversing switch conversion

[GavinL]

I've seen previous threads on this topic before, but thought I'd have a go at my own version. I started by getting hold of a 1275 Midget extension for comparison. Below is this beside a Minor one.

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. The threaded socket in the right hand one is where the reversing light switch goes on the Midget. It is operated by a notch in the spring loaded plunger in the hole to the left on the view from above, which provides the 'gate' when you put the gearbox in reverse. This pin rises in the hole and the notch in its shaft operates the switch. So my plan is to position a push-to-make switch in this hole so that the rising pin operates it, as indicated below.

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So next stage is to make a plate to mount the switch in.

[philthehill]

If I remember correctly the 1275cc Midget and Minor gear sticks are different at the bottom end.
Have you got a 1275cc Midget gear lever to use in the 1275cc Midget gearbox extension?
The Midget gear lever is very short and not so easy to use when fitted to a Midget gearbox installed in a Minor.
I had a midget gearbox installed in my Minor at one time and had to lengthen the Midget gearlever to suit.
Phil

[GavinL]

Ive just tried a Minor gear lever in both and it fits - also measured the dimension from top of housing to bottom of ball socket in both, and they are the same. I think I've read previously that the earlier gear levers differed from the later ones in length.

Actually the Midget extension is going on my Midget in due course, hence the exercise to see if I can come up with a simple way to fit a switch to a Minor extension.

[GavinL]

Next step was to measure the travel of the reverse 'detent' plunger, which is approximately 7mm.

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The travel on the switch is approximately 1.3mm, so I need to work out a way to introduce a suitable spring or similar. In the meantime I've made a plate to experiment on.

[RobThomas]

Gavin. Would it help if someone (me) could weld a boss onto a Minor part to allow it to be threaded just like the Midget one? Are there any other or internal differences? I have a casing here but without any bits inside.

[GavinL]

Rob, thanks for the offer, ( this had been my original thought also) but I think there are too many differences to make adding the Midget boss viable . Mainly that the reverse protection plunger is different - the Midget one is larger in diameter ( you can see this on the view from above), I suspect to accommodate the two recesses in its shaft opposite one another, one for the reversing switch, the other for the reversing selector plunger. We'd also have to modify the reverse protection plunger, or replace it with one with a larger diameter.

Also I'd like to come up with a solution others without access to a workshop could apply, although this is proving more difficult than I had hoped.

[RobThomas]

OK. Out of interest, what part actually pushes the switch? Is it the socket that the bottom of the gearlever drops into? Hard ti picture how it works.

[philthehill]

For those without workshop facilities I would suggest trying to obtain a Midget remote housing Pt No: 22G671 (main casting) and appropriate gear lever and just fit the standard switch https://www.moss-europe.co.uk/switch-re ... soc=406002 .

https://www.moss-europe.co.uk/shop-by-m ... 275cc.html

Searching the web there are several threads as regards fitting a reversing light switch to a Morris Minor gearbox.

[GavinL]

I got my gearbox extension from Andy Jennings at http://www.mg-cars.org.uk/andyjennings/. £40 including postage. I've had quite a few Midget bits from him and always found him reasonably priced and helpful, so good source for common parts.

Rob, the switch plunger locates in a recess in the reverse protection plunger shaft, and the switch operates when the reverse protection plunger rises, and the switch plunger rides up onto the plunger shaft.