> The Auto Stop fill valve is not the same as the pressure regulator. For
some 
> time all non-removable LP tanks on vehicles have required an auto-shutoff
fill 
> valve for good reason - too many accidents when the tanks were overfilled
and 
> the pressure relief valves later had to vent gas (if they weren't jammed
shut 
> - then the tank seams could fail).

This is an important warning.  Shortly after I bought my '89, the propane
stopped working, so assuming it was empty, I went to a local hardware store
to have the tank refilled.  I became suspiscious when it wouldn't accept
any propane, and went to a local propane specialist.  He discovered that
the pressure relief valve was jammed, and the tank had been majorly
overfilled by someone along the way who didn't know how the system worked. 
When he vented it through a fitting, liquid propane, not gas, spilled out,
because of how highly pressurized it was (if I understood him correctly;
I'm no propane expert).  He told me that I had been driving a time bomb;
that if I had not discovered the problem it might have exploded.  So he
vented out the excess propane (he showed me how he could tell when it was
emptied to a safe level even with the valve jammed), and when it does
finally run out I'm going to bring it to him to have it fixed (he is
reasonably certain that he can fix it without needing parts). A major
catastrophe was narrowly averted because I brought the tank to an expert
who knew what he was dealing with.

By the way, this local propane expert was able to repair my old '85's tank
using off-the-shelf generic parts that he had in stock, while I waited, for
about thirty bucks.  This after three big RV specialists and the Dealer had
insisted that only the expensive original-brand parts would fit the tank. 
Of course, this is not to imply that all parts on the tank can be replaced
with off-the-shelf parts, but in my case checking with a few different
places paid off.  (For anyone in the Philly area, the name of the place is
Shaner's Propane, near Pottstown, Pa.  He's not a store, just runs a small
cash business repairing and filling propane tanks.)   

If anyone does need original-equipment propane parts for their Westy, I can
supply them for significanty less than the Dealer.  But I should be your
last resort.  There's at least a chance that a GOOD propane specialist can
save you money, and maybe even save your Westy.

-Ron Salmon
 The Bus Depot
 http://www.busdepot.com