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MG MGB Technical - Wiper park switch

I am after a wiper motor park switch for my B, it is for a two speed motor, but it is a screw in type not a clip in type, which any number of these are for sale, I am happy to buy from anywhere the US, Australia, perhaps not China, thanks A.T
andy tilney

Mk1 GT, I presume, they used a different system to single-speed and Mk2 cars.
Paul Hunt

Paul, No its a GHN5 1969, this motor is the original, its the one it left the factory with,A.T
andy tilney

Is that one speed or two speed? Round motor or square? I'm interested because there might have been two types of GT motor before the 2-speed system with the clip-in park switch and connector, and I've not yet got to the bottom of it.

If you like reply off-line
Paul Hunt

I've seen both on the 14W motors, the screw type is the first version.

It was used on lots of BLMC models from minis to jags.

Moss list the BL part no as 517645A but NlS.

Holdens only show the clip type on their website now as well.

Rimmers list it tho

It may be possible to convert to the clip in type if you cut a suitable hole with a dremel or similar.

Failing that get the later type motor.

Btw, what's wrong with the one you have?

Regards Steve
SR Smith 1

The Rimmer items in that link are the later clip-on type of switch.

The screw-on park switch I have seen is completely different to the later clip on. The screw-on has three brushes that rub against a segmented brass disk in the large gear wheel which makes the required electrical connections for parking. The clip on has a peg that runs on the surface of the gear wheel, drops into a depression where it needs to stop the motor, and that operates a changeover switch inside the clip-on part. You would need to fit the later gear wheel with the later park switch.
Paul Hunt

Hi guys,

I was assuimg this is a Lucus 14W type round bodied motor, is that not the case?
SR Smith 1

Steve Yes you are correct, my old park switch has shorted out and melted, yes I know I can buy a new motor, But I am reluctant, to buy a cheap copy, and have it fail when I am away on a on holiday, A.T
andy tilney

Just found this.

Have dealt with them before for hard to find parts...
SR Smith 1

Doing more research it becomes clearer. That Rimmer link *is* correct in the description, except that the thumbnails below it show motors with the clip-on switch, it's also shown as NLA.

There were two types of motor used on Mk2 cars, they had the same part number but could have one of three suffixes - A, B or D (as is often the case with Lucas parts). A and B used one type of park switch (37H 2734) and brush plate, and D uses another type of park switch (37H 6784) and brush plate. The confusion comes from many parts suppliers showing the later switch under the earlier part number. But these two sites:

and which is definitely an original item.

do show a screw-on part under that number. Both are Mini suppliers, so that may be your best bet. The Somerford one although a sketch does appear to be the right one.

Another Mini supplier mentions the two different types but shows the later switch with the earlier part number, which is why care is needed.
Paul Hunt

Thanks Steve and Paul, thanks to you two I think I have the right part no now, which is 37H2734, I have emailed Somerford minis, and hopefully I will get sorted, my main concern is reliability, not cost, getting a new motor complete for 50-00, for me is not the way to go, I don't want to be a 1,000 miles from home with no wipers, thanks to you two again. A.T
andy tilney

Hi andy,

Glad you it sorted, pleased to help a bit. It's what the forum is all about.
SR Smith 1

New park switch came today, it is NOS and the last one they had, a bargain at 26-00 including P+P.A.T
andy tilney

Drat and double drat!

Bet i'll need one meself for a job soon, and you've bagged the last one.

Wish I'd not said owt now lol.

Seriously though, pleased yr sorted out.

Regards Steve.

SR Smith 1

This thread was discussed between 29/11/2014 and 11/12/2014

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