Repairing & Improving radius arms.

[Peter Laidler]

The reason why is because the bush is a smaller diameter than the bearing - and the tapered plastic sleeve won't fit the other way round. Don't forget that if you have abgrease nipple at each end, the plastic tapered sleeve doesn't direct grease anywhere. It is now just a cover as the grease goes to EXACTLY where it should be

[rich@minispares.com]

The reason why is because the bush is a smaller diameter than the bearing - and the tapered plastic sleeve won't fit the other way round. Don't forget that if you have abgrease nipple at each end, the plastic tapered sleeve doesn't direct grease anywhere. It is now just a cover as the grease goes to EXACTLY where it should be

until it splits, then the arm just fills with grease......

[rolesyboy]

Makes perfect sense. Thanks Peter. (& Rich for the comedy!)

[rich@minispares.com]

Makes perfect sense. Thanks Peter. (& Rich for the comedy!)

mark

i have seen and stripped thousands of core unit radius arms over the years, so have seen every single issue that goes wrong with them

they weigh a ton when they are full of grease!

[Peter Laidler]

It BEGS the question of how - and why does anyone with a modicum of nouse keep pumping the grease gun until it fills the radius arm up? Surely something will be telling them that something's gone horribly wrong somewhere...... or am I missing something? But no matter what, you'll never get the grease between the outer bush and the shaft while it's got a line of lesser resistance at the other end.

[mk1]

The worst example of a rad arm full of grease was when I took a set that Rich had stripped to my powder coater, he put the arms in his oven with about £2000 of other work, turned it on, all the grease ran out of the arm once it was hot & ruined everything else in the oven. I was not a popular bunny that day & have never let Rich forget the incident.

M

[rich@minispares.com]

opps

[canadianminimk1]

Ok, just to clear up my ramblings. It seems that at some point in the life of this car someone turned down one end of the shafts to 0.75" so this is why my new bushings seemed like they were too large.
Anyway, I found a suitable bushing, fitted it and reamed it and all is well. I guess what I thought was a stepped shaft in your article is in fact a worn shaft.
Thanks again and all the best!

Andrew

[wantafaster1]

Many thanks, I've done this mod too, very pleased but they are damned hard to drill.

[69k1100]

The issue with the grease filling the arms (and I have dis assembled several sets with the metal liners still in place) is that there are varying degrees of casting defects inside the bore.

The liners are pressed in, and on more than one occasion they were caught up on a piece of flashing inside the arm, deforming the edge of the sleeve and allowing grease to pass by and enter the arm.

The stupidity of filling the arm with grease isn't the operators fault and certainly not after the car has some miles on it.

The idea is that the Tube makes a sealed chamber around the arm, you pump in grease until the pressure forces grease out either end. This washes any crud that gets in there out (by fresh grease pushing our the old) and should provide fresh grease to both ends (although the needle bearing will receive less due to the distance from the grease hole)

So there is a failing that for the arm that doesn't achieve a good seal with the liner, the first few services will just fill the arm with grease more so when they went to plastic liners.

When I refurbed my arms I used two part instant metal to fill any gaps between the sleeve and the bore, after knocking down any possible obstructions. You could always do this with loctite or epoxy, depends on how good the fit is with your particular arm. I might re-drill the arm as per the guide as well, double sure.

The tubes are still important as even if you re-drill both sides, grease can still leak into the arm if the tube splits, or doesn't make a good seal. Doing some extra prep and careful investigation to make sure the tube is sealed will really improve your chances of greasing things properly.

Cleaning out the grease isn't fun.

[Peter Laidler]

Mmmmmmmmm, 69K emphasises the point that if there's an escape route for the grease in the cover - a line of least resistance - it WILL take it! Liquid is famous for this physical property. And if it's into the arm, then that's where it'll go. But if it's leaking into the arm, guess where it AIN'T goin'. Yep, where you want it.

But if you drill and nipple both ends 69er, as you say, at least the line of least resistance in the FIRST instance, is through the needle roller and the grease grooves machined into the bush. Thereafter it will leech out under the rubber seal at each end. Time to stop pumping.

[69k1100]

yes, the original grease hole location only works if the tube is in place, intact and seals off the cavity inside the arm. If not then you're better off redrilling the feed holes.

people have filled the arms with expanding foam as well to ensure the grease doesn't migrate into the cavity.

[ManyMiniCoopers]

With the MK1 main site being offline, does anyone have the article for modifying radius arms?

[Peter Laidler]

I'm aftraid that I don't have it anymore but did a couple last week for a 998 saloon restorer living nearby/

Incidentally, there aas some conversation about usinf roller bearings in each end. If you do, it's a total waste of time. That's because.......
The swinging arm only rotates through - I seem to remember - about 17 degrees MAX. Then there's the fact that the bearings aren't going to rotate radially around the housing in any case. What they are going to do is that each needke will put a point load onto the housing and shaft. Just what you don't want.

IWhayt you really want is a radial 360 degree bearing. at each end. So you'd be better to have a bronze bush at each end. And then you want a grease nipple to make sure that the grease you inject gets between the bush and the shaft. You don't want grease in the main housing or on the floor or all over the outside. You want it between the fixed bush and shaft at the outer end and between the shaft and the needle roller at the inner end. That's todays rant.

Hopefully someone clever with a bent for computing that can bring the original article up

[gs.davies]

I think I did download this article before the main site closed.

Will check tomorrow and put it on the knack.

[Peter Laidler]

While you're there Gary..... The inboard grease nipple facility has morphed with the other swinging arm modification. That was repairing the inboard stuib axle Helper Spring Support Pin, the HSSP. There were a couple of methods to correct the worn out HSSP. 1) to simply bush it. Pretty successful and 2) take the arm off, cut the HSSP off, drill, tap and replace it. Saves a knackered HSSP and stub axle and a LOT of money too.

Maybe you could find this one too. Shame to loose them

[Dr.Mabo]

I have the article you are looking for.

I have reduced the pdf file to 830 kb. But it's still too large to attach.

I'm open for other options but would prefer ist to upload rather then send it to plenty of interests indiviually.

[mk1]

I sent a copy to Gary this morning, it should be available again shortly.

M

[Peter Laidler]

Thanks - and welcome back.......

[gs.davies]

https://technical.mk1-forum.net/rebuild ... dius-arms/

There you go, more stuff on the technical section