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MG MGA - starter switch

Hi all,
is the starter switch serviceable in any way? Mine has stopped working, but if I push hard enough on the little rod that comes through the switch I can get it to work.
Nigel Munford

You can of course adjust the length of the pull cable, but if it was working fine before, it is most likely that the switch is toast. You could try spraying some contact cleaner into the switch to see if that gets to the contacts and makes a difference. Trouble is that some current replacement switches have a dubious reputation for length of life.

Peter.
P. Tilbury

Use a test light or ohm meter to check continuity between the case and each terminal post as you operate the switch. A common failure is short to ground, in which case the switch would short your battery directly to ground (very bad).

All starter switch problems are internal. The only way to open it is to un-crimp the flange on the metal case. See here:
http://mgaguru.com/mgtech/electric/ss_105.htm
http://mgaguru.com/mgtech/faulty/ft004.htm

Internal contacts may corrode during long storage periods. But these contacts are somewhat self-cleaning during regular use. If the only problem is high resistance contacts, then try cycling the switch repeatedly under load, and it may clean itself up to work properly.
Barney Gaylord

Hi Nigel, as Peter says, some current replacement starter switches are a bit dubious. I had a duff one a few years ago, but it probably served me right for buying it on eBay! It only lasted a few months. Second time round I bought one I think, from Brown and Gammons. The bad one had white nylon insulation, whereas the good one, which has been in service for many thousands of miles, has black rubber insulation round each terminal.
Lindsay Sampford

Nigel

Barney has shown you the workings in his post. Attached is a picture of mine when I opened it up after similar problems to yourself.

I don't have any issues now with my set-up as I have installed a pre-engaged hi-torque starter. With this arrangement the starter switch just carries a small current for the solenoid in the starter motor. The heavy duty starter cable connects directly to the battery cable on the same terminal on the starter switch.

Steve


Steve Gyles

If the contacts are not grounded out then there might be a bit of pitting. In my restoring process, I try to always use the same parts as I took off. Mine was a bit sticky. So I hooked up cordless drill to the shaft.. Spun it slow for a bit in forward and reverse.. and that seemed to clean it up on the inside. Do not spin too fast as you do not want to score the contacts. Little bit of Never seeze on the shaft as it just enters the switch housing.
Ron Bissland

If my memory serves me correctly from the switch in my photo above, the disc is actually free to rotate. So spinning the shaft backwards and forwards is unlikely to have any dramatic cleaning effect except perhaps to bring another area of the disc into contact with the plate - if you are lucky.

Steve
Steve Gyles

I have had trouble with mine. I took them to pieces and cleaned the contacts and then put them back. Luckily both the switches (coupe and roadster) are covered by the heater trunking so my "bodgie" repair is not visible.
Barry Bahnisch

Barry

Some task taking them apart without too much damage! I have just come in from the garage after experimenting with one of my numerous defunct switches.

I can confirm that the copper disc is free to turn on the shaft. With no load (mechanical, not electrical) it will tend to rotate when the shaft is turned, so some people may find that releasing the starter pull cable and rotating the shaft 180 degrees may bring fresh metal into contact. I then put the shaft in my drill chuck and spun it. The disk spins happily away with no load. But when the drill was pulled to bring the disk into contact with the base plate it instantly stopped. I followed Ron's suggestion and altered direction back and forth. After a minute or so I stopped and inspected the results. Absolutely no new shiny metal was observed. So in summary, unless you are able to what Barry did and reassemble a cleaned up starter switch the only chance you have with these switches is to rotate the unloaded shaft slightly with the hope of bringing new, un-arced metal into contact.

Steve
Steve Gyles

My starter switch is finally broken, but I can't start the car to get it to the garage.
Is it possible to jump start the car, by putting leads from the battery to the two connections on the starter switch (ie. the other end of the cable, in the engine bay)
Nigel Munford

Yes Nigel, you can just short across the two terminals of the switch. OR you could use the handle!
Neil MG

The only time I've ever got the handle to work, was when the engine was warm. Just imagine starting the car like that every day!
Nigel Munford

Get the other half to push start you! You need the same heavy duty cable to do the shorting you are talking about.

steve
Steve Gyles

Nigel

Basic question: Why not change it yourself? 5 minute job while you are fiddling around getting access to the terminals for the jump lead.

Steve
Steve Gyles

Steve,
that's a good idea. The garage has ordered the part, so I will collect it, and give it a go. However, my skills are quite limited.!!
Nigel Munford

Switches out of service don't necessarily go bad. When I bought my current car in 1972 it had been converted to ignition switch/solenoid start and it was like that until 6 last summer. I then got round to fitting the correct switch off my original A that I broke up in 1972 (it was a complete rust bucket). After being on the shelf for 42 years the switch is working perfectly.

Paul
Paul Dean

Mine is still in operation after 42 years of on-and-off service -- 4th. motor -- 2nd gearbox and nearly 450,000 miles -- never misses a beat, starts first go! Touch wood!! I have used the handle twice - flat battery!

Barry.
BM Gannon

Steve is right Nigel - a dead easy part to fit even for a cack handed person like me! My replacement switch was off ebay and has been OK so far after 3 years .
Cam Cunningham

Nigel

I think I am correct in saying that there are some pretty shoddy replacement switches around. There are numerous comments in the archives. I wonder where you garage is sourcing the part? Might be worth the ask.

On reflection, with your self confessed limited skills please do take care if you do the job yourself. For safety, first disconnect the battery terminals. The switch, although easy to change, is partially obstructed by the heater air ducting, so access my be your greatest issue - removing one end of the trunking from the blower motor can be fiddlesome, depending on how much flex and compression there is in the trunking.

Fortunately for me I don't have problems with my switch now as I have a starter motor with a built in solenoid so the starter switch carries only a small load and is less susceptible to burning out.

Steve
Steve Gyles

Ah Steve got there before to warn of caution as you create a very hot short if got it wrong. Otherwise straightforward.

Paul

PS In the late 60s/early 70s when my As were in the banger class I used the handle a lot.
Paul Dean

My new switch has arrived. However, it does not have the black rubber feet (As in Barney's second link above) Do I need to transfer them over, or do later switches not need them?
Nigel Munford

I've just answered my own question. The new switch has a plastic cover over the whole of the bottom, which insulates it.
Nigel Munford

Don't forget to remove the battery ground cable before working on the switch.
Keith Lowman

All done, with no fires or electric shocks.
thanks for all the advice
Nigel Munford

Well done. Working ok?

Steve
Steve Gyles

Working well. May go to Shelsey Walsh breakfast club on Sunday.
Nigel Munford

This thread was discussed between 20/10/2014 and 05/03/2015

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