The little rubber donuts (about 3" in diameter, with four bolt holes)
do wear out.  This is one of the few items that I would really recommend
getting from VW, though.  They want about $15 each (the Vanagon uses three
identical ones, but the one inside the car is less prone to rot).  The 
local auto parts place wants about $2.50 each for their version, which
probably is what Ford uses.  The VW ones are really quite superior, though.
The universal replacements are made of layers of fabric embedded in
rubber, like the soles of cheap Hurachi sandles.  VW takes four steel
bushings (these will be the holes) and winds nylon cord around them in a 
pattern.  They then injection-mold (I'd guess) the rubbery cover.  The
cross-woven strands of nylon cord seem a much better idea -- all of the stress
is along the lengths of line -- than the cheapo way, and they look and
feel way better.

Mine really deteriorated in my '80 Westy, and I got to see this internal
construction up-close-and-personal (no mouse-poop, though).  I bought all
three, but the interior one (near the floor) was like new, so now I have
a spare.  Everybody should check the ones under their cars for deterioration
from time to time (like when you check your brake pads).  I didn't.

malcolm

> On my '87, i have found the sticky feel to the on-center position was the
> u-joints that connect the wheel motion to the rack.  one in particular, the
> forwardmost one, is subject to road spray.  i obtained a little relief by
> squirting penetrating oil up under the grease cover on the joint.  best
> course would be to replace the joint.
> 
> it should be a fairly universal (ha!  get it? universal joint?) application
> that can be matched up with a spec book at a FLAPS.
> 
> -dan
>