Started to de-bush my NB arms for NB subframe swap and noticed that NB2 arms have pre-drilled factory center holes. I assume it was for rubber bushings to prevent twisting. I am unsure whether to fill the holes with brazing or a cap of some kind since I am doing delrin and need zerk fittings in different location.

 

One-piece bushing = don’t bother filling extraneous holes
Two-piece bushing = block extraneous holes since they’ll let grease leak before greasing the sleeve

The spots you’ve photographed use one-piece Delrin bushings, IIRC, so maybe don’t worry about it. But check your kit.

 

So the one piece delrin with the spots open won't get too much contamination? I guess greasing the delrin will still have grease escape there first ?

 

If you drill a sufficiently tight hole in the delrin, grease will never make it to the outer surface of the bushing at all. The bushing itself will just block the extraneous hole.

Drill the delrin small enough that you tap the bushing itself along with the arm bore wall.

Maybe file a longitudinal grease groove. Maybe spiral if you’re feeling particularly saucy.

 

thanks afm. Great advice