Steering adjustment lock nut siezed

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Invicta
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Posts: 171
Joined: Mon Jan 29, 2018 9:42 pm
Location: Kent , England

Steering adjustment lock nut siezed

Post by Invicta »

Good day all,
Has anyone had a problem getting the lock nut off the fork top crown of my 1949 Model 18. I had to resort to a hacksaw and a sharp cold chisel to remove mine. My problem was that the threaded tube that is supposed to be fixed into the lower fork crown was turning with the nut. Other than crushing the threaded end in vice grips to try to stop it turning , I had no option but to cut the nut off, as there was no way to prevent the tube from turning. I had soaked it in WD40 for a week and then applied heat with an oxi acetylene torch to no avail. How tight should this tube be in the lower crown. I assume that when assembled it is just an interference fit. Should I drive it out and reassemble it with locktight bearing sealant , or is it safe to leave as it is. It will not pull out and needed a lot of force on an impact socket driven over the nut to make it turn when trying to undo the lock nut. Also does anyone know what metal the fork top crown is made of, it is not steel.
Andy51
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Joined: Thu Mar 31, 2005 1:00 am
Location: BERKS UK

Re: Steering adjustment lock nut siezed

Post by Andy51 »

Never heard of the tube coming loose in the lower fork crown. The upper fork crown is either aluminium alloy (early 50's) or malleable cast iron, easily told apart. Lower crown is very probably malleable cast iron. I seem to remember that the tube is an interference fit in the lower crown, with a circlip for additional security, but check with wiser counsels. I have seen plenty at autojumbles (£10 - 20 price range) and Steve Surby at AMC classic spares probably has them, so it might be better to get a replacement rather than try to repair - I'm not sure I would trust Loctite on such a safety-critical part. Cheers, Andy
Invicta
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Posts: 171
Joined: Mon Jan 29, 2018 9:42 pm
Location: Kent , England

Re: Steering adjustment lock nut siezed

Post by Invicta »

cheers Andy , having got the paint off I can see it is made of some sort of aluminium alloy.
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clive
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Location: LONDON UK

Re: Steering adjustment lock nut siezed

Post by clive »

If replacing be aware there are a number of different types mostly different methods of locking the stanchion in place.
clive
if it ain't broke don't fix
Andy51
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Joined: Thu Mar 31, 2005 1:00 am
Location: BERKS UK

Re: Steering adjustment lock nut siezed

Post by Andy51 »

Stanchions clamped into lower fork crown by stud and nut on earlier machines, then by 3/8 BSF Allen bolt later (53 on?). Otherwise I think they are all interchangeable. Andy
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