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Steering lock shear bolts

Posted: Thu Apr 04, 2024 2:48 pm
by new to this
Are the steering lock shear bolts the same thread size as mini and MG ?

Dave

Re: Steering lock shear bolts

Posted: Thu Apr 04, 2024 8:42 pm
by Carledo
Very probably, as they used the same make of locks throughout BL.

Me being me, I just sub in a couple of 8mm Allen bolts. Then I can get them out easy if I need to!

Steve

Re: Steering lock shear bolts

Posted: Thu Apr 04, 2024 9:26 pm
by new to this
Carledo wrote: Thu Apr 04, 2024 8:42 pm Very probably, as they used the same make of locks throughout BL.

Me being me, I just sub in a couple of 8mm Allen bolts. Then I can get them out easy if I need to!

Steve
James paddocks sell them for £8 each, but found some on E Bay £ 2-45 each, so ordered them hopefully there the same
But i like your idea about Allen head bolts

Dave

Re: Steering lock shear bolts

Posted: Thu Apr 04, 2024 10:23 pm
by cliftyhanger
I also use allen head bolts. I think, just think (and my memory is a bit iffy) they are 5/16UNC thread.
The old ones I often manage to get a grinder in and slot the heads. Then they come out OK.

Re: Steering lock shear bolts

Posted: Fri Apr 05, 2024 12:29 am
by Carledo
cliftyhanger wrote: Thu Apr 04, 2024 10:23 pm I also use allen head bolts. I think, just think (and my memory is a bit iffy) they are 5/16UNC thread.
The old ones I often manage to get a grinder in and slot the heads. Then they come out OK.
I use a centrepop and tap them round, takes a little longer, but a no damage solution. If I need to re-use, I can slot them in the vise!

Not certain all are 8mm but none i've seen are UNF. Maybe UNC as you suggest on earlier cars. For all I know, could just as easily be BSW! BL were very backward in adopting Metric fastenings and still used lot of Imperial stuff well into the 80s. Not so their suppliers, so on a 1980 Sprint the dual circuit master cylinder and servo (made by Girling) have metric threads on unions and studs on an otherwise all Imperial car. It's my bet that the lock manufacturer went metric sooner too!

Steve

Re: Steering lock shear bolts

Posted: Fri Apr 05, 2024 10:07 am
by yorkshire_spam
Largely irrelevant here, but for those interested, on Spitfires even up to the 1500 model the sheer bolts on the lock/ignition assembly are recessed into the lock housing and are UNC. This makes the use of cap-heads tricky. So I ground down some button heads to make something similar to the original, but easier to undo.

Image
(left: original button head, centre: shear bolt removed from column, right: my home made replacement)

Yes....

Posted: Mon Apr 08, 2024 8:59 pm
by sprint95m
That is a good solution Sam





Ian

Re: Steering lock shear bolts

Posted: Sat Apr 27, 2024 5:37 pm
by new to this
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The ignition lock bolts I bought of EBay turned out the wrong ones they should be 5/16 unc so need to order some or may try Steve’s idea about Allen head bolts, just my luck the circlip is also wrong

Re: Steering lock shear bolts

Posted: Sat Apr 27, 2024 7:53 pm
by Carledo
new to this wrote: Sat Apr 27, 2024 5:37 pm Image

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The ignition lock bolts I bought of EBay turned out the wrong ones they should be 5/16 unc so need to order some or may try Steve’s idea about Allen head bolts, just my luck the circlip is also wrong
I have some 5/16" UNC Allen bolts if you need some.

Cheers, Steve

Re: Steering lock shear bolts

Posted: Sat Apr 27, 2024 8:44 pm
by new to this
Carledo wrote: Sat Apr 27, 2024 7:53 pm
new to this wrote: Sat Apr 27, 2024 5:37 pm Image

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The ignition lock bolts I bought of EBay turned out the wrong ones they should be 5/16 unc so need to order some or may try Steve’s idea about Allen head bolts, just my luck the circlip is also wrong
I have some 5/16" UNC Allen bolts if you need some.

Cheers, Steve
Steve

wish I'd seen your reply earlier as I've only just ordered some, do you have the top Circlip for the steering column upper bearing ? I've measured it and its 21mm

Thanks Dave