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MG MGA - Starter screw

On my 1960 A, I found that the screw that holds the cable from the solenoid sides in and out. The cable can be tightened with the nut and the screw will be tight and can't slide, but if its not completely tight, the screw can slide back and forth. Is this normal? I don't think so, but I could be wrong.
Thanks,
Jack
J Weiss

Sounds like a new starter switch is called for Jack. If the contact can move about, it could short out on the inside of the casing, weld together and cause a fire! When obtaining a replacement switch, try to get hold of the sort with the black rubber insulators on the terminals rather than the kind with cream coloured nylon base. I have found the nylon based ones to be unreliable and to cause a slow starter.
Lindsay Sampford

No, no. The stud has to be mounted in insulating bushings. There should be two nuts. The first one holds the stud secure while the second but attaches the cable. The hidden end of the stud connects to another cable inside the starter motor. If the stud is not snug you get a bad electrical connection and no cranking.

I hope you're not missing a brass nut. Those things have an odd thread, not to be found at a local hardware store.
Barney Gaylord


Well I'm glad I'm not the only one who's experienced an oddball brass nut. I tried to replace it from a hardware store and learned that a metric nut will easily "fit" but is extremely wobbly on the stud threads although it never binds.

Is the brass nut also an oddball wrench size? After failure to replace it (it seems to be a very thin nut for the job it has to do), I had to clean up/file down the flats to be able to get a snug fitting 6mm wrench on it.

Do new replacement starters come with this nut on them, or an updated common thread? You can't order this nut from the usual sources, and I wouldn't know what to ask for from specialty suppliers.
JM Morris

Barney, not two nuts on each terminal screw on any of the three starter switches I have. I have the original one which failed in the same way that Jack's has, i.e. starter wire terminal loose in it's rubber bushing, a nylon based one, where the terminals are bonded to the nylon and a modern equivilant of the original stater switch with the terminals bonded to the hard rubber bushes; only one nut per terminal.
Lindsay Sampford

Lindsay - are you referring to the starter switch? I think Barney and Jack are referring to the connection to the solenoid on the starter.
Mike
Mike Ellsmore

Well, there is no solenoid on the MGA, but some people refer to the manual starter switch as a solenoid. I presumed Jack was talking about a loose stud on the starter motor, the one that accepts the cable from the "solenoid" (starter switch). The starter switch and starter motor both use the same odd threaded nuts.
Barney Gaylord

Barney is right. I'm talking about the threaded stud on the starter motor that the thick cable from the "solenoid" attaches. In Moss, its called a solenoid. Anyway, that stud can slide in and out, but doesn't come completely out. Is that normal? If I just tighten the cable so that the stud can't move, will that work?
I discovered this when I noticed the nut holding the cable was almost completely loose.
Thanks,
Jack
J Weiss

In my enthusiasm to try to help with a useful comment I failed to read the posting properly! Sorry Jack and Barney.
I jumped in with both feet because I had a teminal post on a starter switch/"solenoid" come loose about a year ago and a couple of weeks ago the replacement switch failed, allbeit in a different way, so it was still fresh in my mind and I thought Jack was suffering with the same thing.
Lindsay Sampford

Check with a meter that the stud is not shorting to the motor casing! It should be isolated by a bush.
Art Pearse

If I recall correctly, the stud is a 5/16 - 22 British Standard Fine thread and the nut requires a 1/4 Whitworth wrench or socket (or a 6" adjustable Whitworth spanner). For a complete list of Whitworth, BSF and British Association threads (of which many are found on the MGA), see the chart, Standard Threads in the Other Tech Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ Cheers - Dave
David DuBois

This thread was discussed between 29/04/2010 and 02/05/2010

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