Hi guy's.I've been pushing my M21 around for about 22 years now, so we're old mates but she still throws plenty of curly questions for me, so I'm hoping to enlist the help of someone who has some experience with the telescopic front end and 7" brake fitted to the mid fifties civilian m series.

When I last rebuilt her, about 4 years ago I changed the drum side fork leg because the brake back plate locating hole on the ally leg had worn itself elongated and beyond its safe limit. 3 or so years and a very long story later..... She's back together and the forks are finally working well (or at least as well as their going too!) but I'm really stuck with the front brake back plate working its way loose, via the unwinding of the large nut which retains the plate to the bearing carrier.

The wheel was completely rebuilt 4 years ago as well and when I stripped it completely down again this morning, I did have a thrust washed in the wrong place and an extra spacer in there! which shouldn't have been there, but form memory, I was battling with the same issue back then.

Anyway, it's assembled as per the manual now and it's still wanting to unwind! Argh.....

Does anybody have any experience with getting this particular assembly working correctly and safely?

I'm well stumped and would appreciate any advice you might be able to contribute.

Cheers, Ged

email (option): Gd007@bigpond.com

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Some pretty pictures from a few years ago I dug up. Hopefully, someone will recognise that front end......

email (option): Gd007@bigpond.com

G'day Ged,
I think you might have a mismatch of parts.

You state that you have an ally leg but I'm pretty sure that all models around this vintage had iron fork legs.
That aside, the type 3, 7" half width hub has a wheel spindle with a left hand thread that screws into the RH fork leg. With the brake plate nut fastened tightly against the brake plate (and with the spacer between the bearing and the brake plate present) if the spindle is done up tight the brake plate nut is pulled up tight against the fork leg ensuring that the brake plate nut can not come loose.

email (option): spacemonkeym@gmail.com

Thanks Matty. A mismatch of parts indeed...... We have avery long history together and I'm even responsible for some of the mismatching! But the front end is basically standard '54. Type 3 as you've described.

I'd just always assumed the sliders of that era were ally?.... This is actually the third slider I've fitted getting it right! and part of the reason this process has taken 3 years. You can't rush these things.....

So, I reckon I have it fitted now as you've described and as per the manual, but it still wanted to unwind. Since I parked it up and posted earlier, I've gotten back in and nipped up the nut again, putting a fair bit of tension in it and thus starting to bind the wheel up a little. What sort of torque should be on that nut, and the nut on the drive side of the hub as well?

I've also since noticed a gap of maybe 2mm between the nut and the inner face of the fork slider, to which it should be flush and therefore prevented from unwinding. When I replaced that fork leg (the third time), I resprayed it and now I suspect that the bush which slides into the fork slider is probably being prevented from reaching all the way home, thus the 2mm gap.

If I get that correct and close that gap out, do you think that will prevent it unwinding? What sort of torque does that nut want on it?

Thanks for your help. Ged.

email (option): Gd007@bigpond.com

The brake plate nut doesn't need to be gorilla tight just nipped up should be fine same for the LH nut but I think that if the wheel is binding when tight is curious as the spacer is there to prevent this.

I don't quite follow this.

email (option): spacemonkeym@gmail.com

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Thanks Matty. A little hard to get a decent photo at the moment because the sun is shining so beautiful and bright. I can't complain about that.

Yep, I was a little concerned at the binding up as well. I'm suspecting it is exerting pressure on the spacers and then somehow into the two bearing surfaces. Maybe through the thrust wahers. I'd certainly like to back it off.

No, I'm talking about the drum side, where the exposed end of the hollow spindle carrier locates in the inner part of the fork leg and holds the wheel in position while you slide the spindle through. I'm about to go and whip the wheel out again, but I suspect that hole in the fork leg has a little too much paint and primer in there which is stopping the whole assembly sliding all the way home, thus the 2mm gap that you might just be able to make out in the above photo.

The other give away is that the sliding bush on the left hand side is also sitting about 2mm proud.....

Thanks for your help Matty. I'll go and whip it apart and have a look at getting rid of that 2mm gap.

Cheers,

Ged

email (option): Gd007@bigpond.com

Just a thought.
Maybe the RH bearing isn't seated fully allowing the sleeve to sit further to the right. This might also account for the wheel binding.

email (option): spacemonkeym@gmail.com

Hopefully Matty, I got the bearing located correctly yesterday.

And the good news it appears to be finally! sorted..... Gee, that took 3 years.

I whipped the wheel out and had a good look at the stub and the recess in the fork leg. Gave each a good clean up and made sure that it would locate all the way home. I backed the nuts off on both sides of the hub and freed it up, put it all back together making sure I got the hub nut nice and snug against the fork leg, and took it for a good run - one of the advantages of being out in bush! - and voila! It's held up perfectly.

Actually, it was about the best run I've ever had on it in 22 years! It's been back together for probably 4 years, but the forks haven't been right the entire time, so it's probably only run 100k's or so all up. Newly rebuilt motor so it's not even run in yet. As long as I've had it, there is always something else that needs doing and something else not right and something's else to be repaired or replaced or...... But for the first time ever, it finally felt pretty right. Everything tight, nothing rattling just plodding along gloriously. Beautiful! We ran about 20k's or so and she arrived home ticking over nicely and for about the first time ever, I didn't need to grab a tool and tighten something up adjust something or ......


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I guess I can get on with cleaning up some of the cosmetic issues which deteriorated in the intervening 4 years. Oh well, you can't rush these things.

Thanks heaps for you help and advice Matty. Always great to get input from someone who has been there.

Cheers mate.

Ged

email (option): Gd007@bigpond.com

Glad to here it's sorted.
Nice bike by the way

email (option): spacemonkeym@gmail.com