6 replies to this topic

[OllieTheWelder]

Hi, been off the forum for a while but after passing my test on Tuesday I'm wanting to get my mini road worthy again.

 

When I was fitting new cones to the rear subframe, I noticed the radius arms wouldn't move freely and one was completely seized. I presume this would be due to it being sat for so long? I spoke to my tutor at college who used to restore mini's and he said he'd be able to give me a hand reaming them in the workshop facilities. However after doing some research i noticed some people mentioning that a special ream would be required, is this the case or would a normal reaming tool work sufficiently (13/16")? There are lathes in the workshop that I could probably use if it's alignment that required the special reamer? 

 

Or should I not waste my time possibly ruining the ones I have and just buy refurbed ones from Minispares?

 

Thanks, Ollie.

[tiger99]

OK, as you have access to a machine shop, I shall try to explain what you need to achieve, You or your tutor will know whether that is achievable with your equipment.

 

The special reamer is in fact a long reamer with a guide bush. The bush fits into the arm, where the needle roller goes, to keep the reamer in line as it reams the bronze bush at the other end. So your problem is basically, can you keep a reamer in line accurately?

 

If you have a reamer with a Morse taper shank, and a female Morse extension, you may be able to turn the extension to a suitable size, and of course making a guide bush is not difficult, so you may be able to do it that way. Or, if you could clamp the arm VERY firmly (how, it is an awkward shape?) on the lathe carriage, adjusted so that it was centred on headstock and tailstock (you could turn up a centering rod to assist), then mount the reamer in headstock and wind the carriage across to feed the rotating reamer into the arm. There are other possibilities too, The key thing is that the bore of the bush ends up as closely as possible to being concentric with the bore that holds the needle roller, so the pivot pin runs straight and parallel in both its bearings.

 

Please do let us know how you get on, and some pictures would be nice, if possible.

[Alex_B]

I think it would be worth trying if you have the equipment, worst case scenario is you cannot do it and then get them exchanged at minispares? 

[OllieTheWelder]

OK, as you have access to a machine shop, I shall try to explain what you need to achieve, You or your tutor will know whether that is achievable with your equipment.

 

The special reamer is in fact a long reamer with a guide bush. The bush fits into the arm, where the needle roller goes, to keep the reamer in line as it reams the bronze bush at the other end. So your problem is basically, can you keep a reamer in line accurately?

 

If you have a reamer with a Morse taper shank, and a female Morse extension, you may be able to turn the extension to a suitable size, and of course making a guide bush is not difficult, so you may be able to do it that way. Or, if you could clamp the arm VERY firmly (how, it is an awkward shape?) on the lathe carriage, adjusted so that it was centred on headstock and tailstock (you could turn up a centering rod to assist), then mount the reamer in headstock and wind the carriage across to feed the rotating reamer into the arm. There are other possibilities too, The key thing is that the bore of the bush ends up as closely as possible to being concentric with the bore that holds the needle roller, so the pivot pin runs straight and parallel in both its bearings.

 

Please do let us know how you get on, and some pictures would be nice, if possible.

 

Thanks for that, I wont be seeing my tutor for around 2 weeks but that gives me the opportunity to remove the radius arms from the car. Clamping the radius arms into the lathe is the thing that concerns me due to the odd shape as you mentioned. I'll have a word with him and if I do end up going down that route I'll picture it for other people to use as a reference.

 

 

I think it would be worth trying if you have the equipment, worst case scenario is you cannot do it and then get them exchanged at minispares? 

 

Yeah I also think it's worth a go, hopefully if it does go wrong it'll only damage the bushes so should still be able to exchange them with minispares.

[xrocketengineer]

This is how I did it with mine. This is not the factory correct way, and not necessarily the best way, but it will give you and idea of what it takes to do it.

 

http://www.theminifo...th-radius-arms/

[OllieTheWelder]

This is how I did it with mine. This is not the factory correct way, and not necessarily the best way, but it will give you and idea of what it takes to do it.

 

http://www.theminifo...th-radius-arms/

 

Cheers, that'll probably make more sense to me when I remove the radius arms and know what I'm looking at :)

[tiger99]

I did not want to tell you how I did one, in an emergency, way back in about 1969. It lasted for well over 50k miles after bodging it, so maybe my method was not so bad, but I was thinking that with access to a real machine shop there would be a better way, so please do show us how you get on.

 

Anyway, what I did was to leave the needle roller temporarily in place, and make a crude reamer by putting a single groove (two would be better) in the worn end of the old shaft, extending beyond the worn area. I then welded an old wheel brace from a previous car to the threaded end of the shaft, as an easy way of turning it.

 

Winding it in from the needle roller end, the worn part passed through the new bush, and gradually the unworn part entered the bush and brought it to the correct size. I did both arms with the same bodged-up tool. Then I extracted the needle roller and grease tube and fitted the new ones, steel grease tubes in those days.