When I bought my 85 westy the end link on one side was missing. I have
since found out that end link failure on early vanagons is common.I have
seen many damaged or missing end links,since.  Those end links are about
$60, and dummy me bought a post 85 end link used from go westy for $40 to
replace it.Course it didnt fit ,and I sent it back.You can get one at a
junkyard for $5.They are called "dog leg" end links,and are cast iorn.Even
the threads are cast iorn, and this is where they break. The late vanagon
end links are called straight end links.They are regular steel.

You can use a sway bar from a post 85 vanagon which is 19mm diameter as
opposed to the 21mm, you got.Only the 4 bushings need replacing to
accomodate this.I think there will be less stressing of the end links this
way.

Also, an early 21mm sway bar can be fitted into a post 85 vanagon by using
a early vanagon sway bar and 4 larger bushings.