Has anyone ever replaced the outer C from brake line out . With 91 and up to eliminate screw in taper preload sleeve on 1990 and down.

 

I am a little confused here. My impression is that all the D30s in XJs had the type you are wanting to go to. Mine is an 86 and all the pre 91s I have found in the pick and pulls don't have that sleeve.
But setting that aside, why would you want to to the other route? That sleeve means that your upper ball joint has a full ball in it. The others that slide only have a half ball with a stud on the flat upper side. Not nearly strong or wear resistant. I would love to have had that type.

 

Both of my 89 CAD axles have that brass insert, and I have swapped to the newer style knuckle before (not because I was worried about that insert), obviously you'll need new calipers, I think if you use 89 hubs and 89 rotors you can do that, but if you use the newer hubs you'll for sure need the new style rotors. The ball joints are otherwise identical, it's a pretty straightforward swap.

 

Was planning on using whole assembly from ball joint and brake line in. Its not that I dont trust the sleeve. When I did ball joins years back one of my inserts was unmoveable. Planning on new ball joint soon so its easier to find newer than older ones.

 

i have done that, but not to get rid of the sleeve, matter of fact, i don't recall that sleeve.

i did the swap to get rid of the brake caliper brackets. i used moog ball joints and delco premium calipers/pads.