Morris Minor Owners Club

Does anyone know what the thread is in the Pickup cab back for the spare wheel captive nut. I need to mount my wider Lp917 spare wheel to the cab back and the existing long bolt for the standard 3.5J wheel now isnt long enough. So a solution to my problem I thought is to make a long stud instead of a long bolt and put a wing nut on the end, making mounting and fastening the spare wheel easier to line up etc.

I have a bolt already but I know that the thread on it isnt right and its always just bitten on the threads and just isnt right. I cant get a thread gauge into the captive threads sufficiently to tell what it is. I suspect its a UNF though?

Many thanks

Steve

Its definately a BSF thread as are all the bodywork and suspennsion nuts and bolts on a Minor. Not sure which one exactly but I can check if you still need to know.