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MG MGA - help changing brake light switch

Hi All,

I'm having trouble replacing a faulty brake light switch. It's really hard to get to. I've removed the universal joint on the steering column to improve access and am using a box spanner to undo the switch but it's in there good and tight. Probably over tightened on a bench when restored by an overzealous mechanic thinking "we don't want that leaking". Any suggestions how I can loosen it without breaking the brake pipes?

Many thanks

Jason
Jason Ogelman

Don't bother. Replacements are often unreliable. Because of that, plus the risk of tearing out the pipework if the switch is fitted too tight, a few owners (me included) have mounted a mechanical switch on a simple s/metal bracket down on the foot pedal.
Graeme Williams

Jason
The four way union that the switch goes into is held in place by a nut on a stud coming from the chassis, so, uncouple the brake pipes then remove the nut on the stud and lift away the union with the switch still in place. Then get it into a vice.

Alternatively, for longevity and reliability, just extend the wires from the hydraulic switch and put a mechanical switch on the brake pedal, leaving the dud hydraulic switch in place as a plug. It'll save you having to bleed the brakes too.

Regards
Colin
Colin Manley

See here: http://mgaguru.com/mgtech/hydraulics/ht114.htm

Do please install a good one that works. Try to avoid installing a bad one, as you would be replacing it again in 5000 to 8000 miles. Find a list of good and bad switches here:
http://mgaguru.com/mgtech/electric/et119.htm
http://mgaguru.com/mgtech/electric/et119a.htm

And reports on good and bad switches here:
http://mgaguru.com/mgtech/electric/et119b.htm
http://mgaguru.com/mgtech/electric/et119g.htm
http://mgaguru.com/mgtech/electric/et119g2.htm
http://mgaguru.com/mgtech/electric/et119g3.htmhttp://mgaguru.com/mgtech/electric/et119x.htm
http://mgaguru.com/mgtech/electric/et119x2.htm
http://mgaguru.com/mgtech/faulty/ft071.htm

The 5-way block holds the switch on top with four pipes connected to the side ports. See pretty good photo here:
http://mgaguru.com/mgtech/electric/pics/brake_sw1.jpg

If the switch is not too tight it can be removed fairly easily with deep socket and long extensions to get the wrench handle above the body cowl. Before installing a new switch, tape the tapered pipe threads with Teflon tape for sealing, and then don't torque it up too tight next time.

That block is secured with only one stud on the frame with washers and a nut on top. The four steel pipes may or may not be stiff enough to handle the torque of removing the switch (usually okay, but occasionally not). In the photo noted, try jamming a big screwdriver in between the shoulder on the block and the center weld ridge on the frame while you apply anti-clockwise torque with the socket wrench.

More brake switch changes:
http://mgaguru.com/tales/mobile5.htm
July 28-29, 2014
http://mgaguru.com/tales/mobile2/1378.jpg

http://mgaguru.com/tales/mobile9.htm
September 26, 2014:
http://mgaguru.com/tales/mobile3/2225.jpg

http://mgaguru.com/tales/mobile18.htm
February 13, 2015:
http://mgaguru.com/tales/mobile5/4149.jpg

http://mgaguru.com/tales/mobile22.htm
April 1, 2015:
http://mgaguru.com/tales/mobile6/1067.jpg

http://mgaguru.com/tales/mobile26.htm
June 3, 2015:
http://mgaguru.com/tales/mobile8/2552.jpg

http://mgaguru.com/tales/mobile28.htm
July 3, 2015:
http://mgaguru.com/tales/mobile8/3170.jpg

And finally a winner:
Duralast RB01 (made in Spain) from Advance Auto Parts
http://mgaguru.com/tales/mobile8/3173.jpg

Then another winner:
Park-Remax PB707/ES1662
http://mgaguru.com/tales/mobile9/3418.jpg
barneymg

thank you all
Jason Ogelman

I've decided to do a mod and install a mechanical switch as it's not budging. Would anyone be able to post a pic of how they installed their mechanical one? Would be very grateful as I'm a bit of a novice but good with my hands.

Many thanks again,

Jason
Jason Ogelman

A bit rough and ready. I used the bolt which acts as the pivot for the pedals. The other half of the tin work is a mirror of what you see here.
The switch is adjustable backwards and forwards to get the activation point right. I think it probably came from ebay and it needs to be "make" on release because braking moves the pedal away from the switch.
Electrically you can pick up the wires from the hydraulic switch.

Graeme Williams

This is an ideas sketch I produced at the time. Don't try measuring anything, I was making it up as I went along but I think the shape isn't too far out.

Graeme Williams

You could also mount a Lucas MG-stye mechanical brake switch, "remotely" connected by a spring link. Pre War MG's and the TC's used such a (51C) mechanical switch, before switching to the pressure type for the TD. The MMM MG's used a similar switch, but one actuated by a lever arrangement. You can find the old Lucas style switch here #350 which is quite a good bargain compared to the usual suspects price.

http://www.vintagemotorspares.com/phdi/p1.nsf/supppages/hodge?opendocument&part=4

In that listing, next to it (#351) shows a switch with a spring link attached. Here is a pic of the original switch in a TC (wrong side showing to see the spring link). It is mounted on a little "shelf" towards the front of car, ahead of the brake pedal. As you can see, it is an inch or so above the chain link for the TC mechanical clutch. A shelf, or something to mount upon, is needed for this switch to cover up the internals from the bottom.


D mckellar

This thread was discussed between 22/03/2017 and 31/03/2017

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