Series MM wheel bolt taper angle

[RobThomas]

Has anyone got some MM wheel bolts and would be able to measure the angle of the taper. Might be 45, 66 or 60 degrees?

Easy way perhaps to put one over a sheet of paper with lines drawn at 60 and 66 degrees? Even a good photo up here might help me.

Thanks.

Rob

[Sleeper]

MM are 66 degrees , Ford 60 degrees

2017_1110wheelnuts0002.JPG (262.81 KiB) Viewed 3157 times

MM top
Ford middle
Modified bottom

Just been altering my nuts to suit Escort axle,Morris wheels

John

[RobThomas]

Thanks, Sleeper. Those nuts are post Series MM at 3/8 unf. I guess I should have elaborated.

The Series MM ones are bolts instead of nuts. I've just been over to where the old axle is stored and the Series MM uses a 7/16x20 UNF bolt with a 5/8 (15.8mm) spanner with what seems to be a 60 degree taper (Oh, boy, did I get WET!). I had looked at the later Minor nuts a while ago and noticed the strange taper angle. The Series MM is the same as the Ford Crapri so if I can get some HT studs from cut-down bolts then I can use Ford wheelnuts to do the job whilst increasing the bearing surface are to reduce the chances of the wheel bolt pulling through the wheel, which can happen on the series MM. Magnette and MGA will also do the job.

Early Series MM seems to be BSF threads with a bigger head on the nut. Last of the Series MM axles in the early Series 2 uses 7/16x20 UNF but with a bigger head, which is what I need to replicate.

Soooo, I just need 16 Ford wheelnuts and 16 HT bolts with the heads cut off. Job done!

By my guestimation the threaded section needs to be 1.5 inches long.

I see that there was a 1/2-ton Mini with 7/16 instead of 3/8 studs and that the MGB has 1/2 inch studs, should anyone want to start playing around.

[Dean]

http://www.morrisminorspares.com/wheels ... mm-p831449

http://www.morrisminorspares.com/wheels ... ii-p831451

I bought mine from ESM with no pull through issues.

[RobThomas]

Mine bottom out before the taper clamps the wheel on. Only on one wheel, and it had a temporary fix with a thin washer under each bolt head. I'd rather fix it with something more permanent. The hardest part is finding 40mm of 10.9 threaded rod.

[Dean]

The bolt bottoms out? Are the holes in the wheel worn and over size?

Have you thought of rolling yourself a cone taper from sheet to slide over the bolt taper? A bit like a modern wheel nuts, you could make it in a way that the cone taper locks on the wheel as the bolt rotates preventing future wear. You could then use stock wheel bolts.

[RobThomas]

Already done that as a temporary fix. The bolts are still a weak point in the design with heads that are too small. The Wolseley 4/44 wheel nut is ideal with the same thread and a larger nut. It uses studs instead of bolts so it is hard to see why Morris didn't change over earlier.

drum1.jpg (366.43 KiB) Viewed 3028 times

[Dean]

I'm sure Mike Perry did a fix on his MM converting to studs and nuts, I don't think he's been on line for while, hope he is okay.

I'll go through some of his posts, I think he described what he did on here somewhere.

Edit:
viewtopic.php?f=19&t=51321&hilit=drum


Further reading:
viewtopic.php?f=19&t=45738&p=456681&hilit=drum#p456681

Soon after purchasing my Series MM in 1978 I noticed a knocking noise in time with the wheel rotation which turned out to be loose wheel bolts or at least the bolts were tight but the wheel was still loose. It was fitted with 5/8 af head wheel bolts which had worn the bolt holes in the wheel. Whilst pondering a solution I spotted a wheel nut in my nuts and bolts tin which had the same thread as the MM wheel bolt, the later 7/16 unf not the early bsf, and had a 3/4 af head. Further searching found a 7/16 unf threaded bolt.
I screwed the bolt through from the inside of the drum, fitted the wheel and tightened the new wheel nut which solved the problem. I bought 16 bolts and wheel nuts , fitted the bolts, cut the heads off and had them welded to the drums.
As has been said, when the hub caps are fitted who can tell.
Also available are 3/8 whit head wheel bolts fitted to early Series IIs, however if you have the earlier bsf thread wheel bolts your options are somewhat limited


https://www.ebay.co.uk/i/172063576292?chn=ps

Just need the bolts now.

[RobThomas]

Thanks, Dean.

Those are the nuts I was looking at and I've got some 8.8 HT setscrews (2") on order. The hardest part was deciding what grade of thread I could utilise. Most moderns use 10.9 grade but I couldn't find anything with the right dimensions but 8.8 seems to be enough, especially as the later cars went down from 7/16 to 3/8 for the studs.

It looks like Mike went down the same road as me, then. There seems to always be someone who has gone through the same problem but first you have to find 'em.

[Dean]

No problem Rob, happy to help. There's just one thing I've been pondering. I wasn't aware you could weld cast iron, due to the nature of the crystal grain structure. So, if the bolt were to become detached from the drum, you could struggle to tighten the wheel nut.

You can weld cast steel though, do we know if the faithful moggy drum is cast iron or cast steel?

Wouldn't it be better (reliable in case we don't know) to weld the threaded bolt into the wheel nut and create another wheel bolt again?

[RobThomas]

I was planning to cut the head off of the setscrew and loctite it into the existing bolt hole in the hub so I could then just run the nut down it like a later car.
I've TIG brazed some cast iron before and it has lasted quite well but I wouldn't want to do it on anything critical ( I'm not that good!)

[Dean]

Sounds like a plan

[RobThomas]

Result. Just need the new nuts to turn up.

Clockwise...9 o'clock is a (used) 7/16 wheelnut on a grade 5(roughly equivalent to 8.8 metric grade) bolt...12 o'clock is a standard Morris disaster,...3 o'clock is a Morris bolt with a hardened steel washer.

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[Dean]

That's a huge difference. Nice one.

[philthehill]

Rob
What is the difference is size across the flats of the original stud/nut and the replacement nut?
Phil

[RobThomas]

Off the to of my head it goes from circa 15mm to circa 19mm. I'll check it out tomorrow, if I can.

[RobThomas]

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Hopefully this shows the original wheel bolt protruding enough to bottom out the thread prior to clamping the wheel on. Problem (hopefully) solved

[les]

Now where have I seen hands like that before? Ahh yes, I remember, good/bad old days, happily no more. Well I live in hope!

[RobThomas]

oooooooh, you shouldn't have said that!!!

You've uttered a challenge to the Gremlins. Now you're in for it!