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 Post subject: Re: Rear radius arms
PostPosted: Sat Oct 21, 2017 10:38 am 
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Posts: 306
I get the idea but can you do some photos so those of us with less engineering experience can see what's going on?


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 Post subject: Re: Rear radius arms
PostPosted: Sat Oct 21, 2017 12:00 pm 
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Joined: Sat Jul 15, 2017 5:35 pm
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Location: Abingdon Oxfordshire
Got that Docka. We're going to put this up on the forum as a simple easy to follow and not too technical article in a month or so. That's why I'm picking everyone's brains.


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 Post subject: Re: Rear radius arms
PostPosted: Sat Oct 21, 2017 1:28 pm 
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Joined: Fri Jun 25, 2010 5:37 pm
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Location: N/E England Where the SAND is GOLDEN and the sea is always COLD!!
Peter Laidler wrote:
Got that Docka. We're going to put this up on the forum as a simple easy to follow and not too technical article in a month or so. That's why I'm picking everyone's brains.

While you are on with this then Peter you could even use some of these (chasis lubrication) fittings and grease them from the drivers seat :o
http://www.lubeline.co.uk/Downloads/Int ... ttings.pdf :shock:


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 Post subject: Re: Rear radius arms
PostPosted: Sat Oct 21, 2017 3:28 pm 
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Location: N/E England Where the SAND is GOLDEN and the sea is always COLD!!
Hi Peter although I was'nt realy serious about greasing from the drivers seat :oops: (although it could be done) if the access is dificult for those without access to ramps, it would be easy enough to place the grease nipples on the rear sub frame.
Ronnie ;)


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 Post subject: Re: Rear radius arms
PostPosted: Sat Oct 21, 2017 5:54 pm 
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Location: Abingdon Oxfordshire
I realise that you weren't serious Ronnie and I did have a little chuckle to myself at the idea. I've been underneath mine this afternoon faffing about and having a loook-see. I'm confident that Iain's idea of an angled downwards grease point(s) would be simple to get at, to the extent that even if you couldn't see them, you can easily feel them and click a grease gun onto the nipple. It's just an idea....... We also established using a knackered shaft that using a good quality centre drill to break through the case hardening (felt like a micron thick to me!!!) and another decent drill cuts through the shaft like butter. Same as boring in from the other end and threading. Will get dopey son to put a photo of the modified shaft up for starters. We've also bored right through so that there's TWO grease exit points under the needles and bush. Been an interesting little project.


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 Post subject: Re: Rear radius arms
PostPosted: Wed Oct 25, 2017 11:59 am 
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Location: Abingdon Oxfordshire
Back to this thread again and the subject of the rear swinging arm pivot shafts. Can any of the real teccies out there in Mk1 forumland tell or give me one earthly reason why the shaft has an almost redundant needle roller bearing on the inner end and a more suited bronze bush on the outer end. It defies mechanical belief.
None of my era engineering pals can understand either. All saying that it's like that because........ er....., it's always been like that. And in any case the swinging arm doesn't actually ROTATE as we think of rotation...... It rotationally swings slightly, like a pendulum! And in that mechanical application, according to the mechanics of bearings (see Machinery's.....) bushes are the correct application for this because in this case, the same part/sector/needle/roller bearing remains in place (due to lack of actual 360 degree rotation of course) and constantly takes all of the load. Whereas a BUSH takes the same load of course, but it's spread over half of its surface area.

As you're aware, we're writing a technically simple paper for the forum regards rebuilding the swinging arm assemblies and would like to include all the variables - and answers. Many heads are better than the 4 of us doing the project (2 engineers, a chemist and metallurgist), especially the wise mini experts who've done it and thought about it for a long time.

Many thanks


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 Post subject: Re: Rear radius arms
PostPosted: Wed Oct 25, 2017 12:06 pm 
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Location: Oop North where it's dark & cold nearly all the time.
That is a question I have often asked myself.

I have no idea as to the correct answer & would love to hear a plausible explanation, if indeed there is one.

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(I'm a very friendly Lion called Parsley)


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 Post subject: Re: Rear radius arms
PostPosted: Wed Oct 25, 2017 12:40 pm 
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If you think about it the UJ's in rear wheel drive propshafts, the Hardy spicer driveshaft couplings and even the front suspension upper arms all have needle rollers in them and all move far less than the rear arm on the mini.

I might be incorrect here but didn't the Metro have needles both ends?

As far as I can recall bushes require a constant source of lubrication to work properly (just like a crank or rod bearing). As can be seen by the rather poor state of many Mini rears this does not happen. Even ones maintained by fastidious owners wear more rapidly on the bushed end than on the needle end.

I would think that a needle roller would have several advantages over a bush, the primary being that they trap lubricant in the cage and therefore are much less prone to dry failure/wear. The second is they are much less sensitive to dirt and partial wear.

On a bush once the surface lubricant breaks down the bush is in direct contact with the shaft and then it will fail. This can be due to lack of maintenance or dirt cutting the film by damaging the machined surface.

The swinging arms on all of the motorcycles parked at my house all have a needle roller at one side and a dual ball roller at the other, there is not a single bushed bearing surface there.

The only bushed bearings on a motorcycle I can think of are the crank and camshafts and the front forks and they all have constant sealed lubrication, so thinking the other way I am surprised that the Mini rear arm has a bush in the end of it and not a needle roller. ;) ;) :D


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 Post subject: Re: Rear radius arms
PostPosted: Wed Oct 25, 2017 12:55 pm 
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Do Metro rear arms fit Minis? or can be modified?


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 Post subject: Re: Rear radius arms
PostPosted: Wed Oct 25, 2017 1:02 pm 
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I don't think they will without a lot of modification.

On this thread about a half way down the page there is a direct comparison of the Metro arm vs the mini one, albeit an early welded one.

http://www.16vminiclub.com/showthread.php?t=511&page=23

Apparently they are needle rollers both ends as well.
http://www.ebay.ie/itm/Austin-Metro-1-0 ... Swqu9U3JjV


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