An insufficient seal at the outer ends of the upper control arm bushing eld
can cause premature wear to the bushings.  Visually inspect the bushings
as follows to determine if replacement is necessary.

NOTE
When checking the bushings, both front wheels must be on the ground.

* Bolt head or nut/washer must be postioned in center of bonded rubber
  bushing.
* If bolt head or nut/washer comes in contact with supporting ring
  (arrow), wear limit has been reached and bushing must be replaced.

<picture shows the hex-head bolt of the upper control arm, which
passes through the bushings. the 'arrow' seems to be pointing to the
'eccentric washer' which is shown in the Bentley book on page 40.2.>

this same information is also shown on page 40.5a of the July 15, 1991
edition of the Bentley Vanagon Manual.