I've got an 89 Westy and an 87 bus.  Both with A/C (though they both
malfunction).  The Westy has been R134A'ed and cools fine, except that
condensation drips from front edge of cabinet (so I DO NOT use it).
The 87 is still R12, but it was discharged when I bought it.  Had a buddy who is an HVAC mechanic for commercial buildings charge it and
test for leaks - found it coming from evaporator housing.

Bentley said it didn't need to be discharged to lower housing.  So I
followed procedures and removed ductwork from front to back and then
unscrewed the housing - to learn that the entire unit comes down, not
just the housing!!  I thought the evaporator would be mounted on an
overhead bracket and would stay up with the housing coming down to
access it.  Oh well, it's still easier than working under a hood.

But my Westy - I checked the drain hose valves under the air scoops
and they were clean.  So I'm thinking either the hoses came off the
drip pan, or the pan is cracked.  Who knows, what was done up there
when the PO's A/C mechanic converted to R134A last year ?  But in
the Bentley on page 76.9, it appears that in the Westy, the cabinet
comes down and leaves the evaporator up.  Can anyone who has lowered
their A/C cabinet in their Westy confirm this ?

Thanks
Trying to be cool
Dave L.