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MG MGA - Brake light switch replacement

I've already added a comment to Brian's current post on Brake Light Switch Conversion, but as I've decided to go the route of a replacement hydraulic switch rather than the (more sensible?) mechanical version, I thought it probably warrants a threads of its own.

The new switch supplied by MGOC is made by FAE (part no 20010) which Barney's site warns against having had one fail after just 250 miles!! But as that's what I've got, that's what I'll be fitting.

I'm currently waiting for a 26mm socket to be delivered today, to fit the old unit before trying to remove it, but as Steve G has said, access down there is not great. Because the unit is located pretty well directly underneath the steering column I'm already resigned to thinking that I might have to remove that first in order to give myself enough room to work, particularly as I'll need to make sure that the 4-way adapter doesn't move if I need to give it some wellie.

Before I start, has anyone got any tips? Thanks
Robert Sinclair

Hi Robert, you should fit a relay to the switch it will reduce the internal arcing and the switch will last longer.
I Hazeldine

http://www.lmslichfieldltd.com if you are concerned about quality these people still have a few NOS Lucas ones in stock,and at a good price
Andy Tilney

Andy

The only one I found on the site says not available, but maybe if you had a part number I would find the one you refer to

I too have an original 1950s switch

Dominic
Dominic Clancy

Dominic the part number of these NOS Lucas brake light switches is SMB423, When I last contacted them they said they still had a few left in stock,
Andy Tilney

So, the good news is that the 26mm socket fits the switch perfectly and with a couple of extension bars joined together I've got plenty of clearance to get some real pressure on the ratchet … but the bad news is that the switch doesn't want to part company from the adapter. I've tried to stop it turning by wedging a large flat-headed screwdriver between one of the adapter arms and the spine of the chassis member, but it still won't stay put. Has anyone got any suggestions?
Robert Sinclair

Cut a piece of sturdy hard wood (Tasmanian Oak) to brace against starter motor or engine block, notch out the ends to the shape it rest against. Interestingly the switches I have changed needed a 7/8 AF deep socket.
Mike
Mike Ellsmore

Mike

The modern replacements are smaller than the originals, although I don't know the sizes, offhand.

I do have a collection of used original switches, so can measure one.
Dave O'Neill 2

I did try a piece of hardwood, as Mike suggested, but to no avail, so have just returned from my local MG garage near Reading where we finally succeeded. It needed a 2ft lever bar to hold the adapter in place and a 3ft ratchet handle to get enough force to turn the switch - more than I would have dared to try at home!
We then tightened it up again for me to complete the job at home, but having read the comments about replacement switches I have decided not to fit the FAE one but to get a Lucas one instead.
Thanks Andy for giving us the Lucas part number, but unfortunately LMS Lichfield are out of stock. If anybody else wants to go this route, Auto Electrical Spares have them in stock (https://www.autoelectricalspares.co.uk) but just the flat terminal version, not the screw terminals. Their price is £3.74 + £4.00 UK delivery + VAT, so £8.49 in total.
I've now got one ordered so hopefully will be back on the road in a couple days.
Thanks for all the help and advice.
Robert
Robert Sinclair

If you've bought C16062(A) (Lucar spade fittings) then it's 7/8" deep socket.
Nigel Atkins

Also, a 'modern' Lucas switch will probably not last very long, from what I've heard.
Dave O'Neill 2

Hi Robert.
Interesting to read your thread regarding brake lights. I decided to go mechanical and bought a switch from AES. I have posted a photo on my thread which you may have seen. I have noticed that the switch can be adjusted to opetate with the lightest pressure which I think gives an earlier notice to following vehicles.
Brian
Brian Paddon

See my new thread entitles Lucas Selling FAE Parts
Robert Sinclair

This thread was discussed between 11/05/2019 and 16/05/2019

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