Radius Arm Ball joint....

[Denis Sweeney]

Hi folks, just putting the front axle together after some modifications involving the removal of the radius arms, as I have stripped it all down I am replacing the brass cups, bolt, spring and nut all with new.
When I dismantled the arms, at the ball joint there was a double nut on the bolt, I assume that one of the nuts was there acting as a lock nut?
However looking at a reprint I have of the twentieth addition "List of Spare Parts" publication 1218 which would cover my ARQ Ruby, there is a picture on page 44 of the radius arms and ball joint part BM123 and in addition what I presume to be the associated Bolt, Castellated nut and Split Pin parts BM120, 121 & 122, but no spring is listed or shown. It also does not tabulate any of these parts numbers. 
However the new set I have comprises a single Bolt, Nut and Spring, but not a castellated nut and no split pin. 
So should there be a castellated nut and split pin? 
My gut feel is that there should be some form of fixing, be it a retaining split pin or lock nut or some other form of preventing the nut form falling off, what have others done here?
But my other concern is just how tight should the ball joint be??
All suggestions gratefully received.
Cheers Denis S

[AustinWood]

I use a Nyloc nut

[Robert Leigh]

I suggest that without a spring, which is how it appears in the parts list, the nut should be fully tightened and then slackened by a 'notch' before the split pin is inserted. It does not show clearly in the list but the bolt is a special and is waisted so that the radius arms and cups can rotate a bit on the ball, with the cups and arms being a close fit on the full diameter parts of the bolt. You rarely find the correct bolt in my experience of dismantling these. David Cochrane and probably other cherished suppliers do have the right bits and can probably advise you more specifically.