Volks,
In case you haven't noticed yet, the small thumb screw at bottom center of
the P-Trap under the sink is vulnerable to rusting out. When it does you
will have a leak under your sink. The replacement part is sold by Bus Depot
and others for about $40.00!!!
Last fall Harald up on the Olympic Peninsula posted that he had found a
replacement P-Trap at an RV supply place up in Canada for about $C12.00.
Today I found an EXACT replacement (M.A.S. Model DT-151X, NSF-24) at Allied
Trailer (an RV supply place) in Sacramento, CA for $5.95!!!!!!!!!!!!!!!!!!
But I bought the other model for $6.23 (Admiral A-60-C, NSF-24) that seems
less likely to rust with the screw off to the side and out of the water.
With the Admiral you have to pop take the screw out and pop the bowl to
drain it. That's slightly harder than draining through the thumb hold screw
of the stock model, but it will last a lot longer I think.  My threaded
metal strainer holder fit both models.
So look in your local RV Part store for the P-Trap. If they don't have it,
call Allied Trialer and they'll mail it to you.
Thanks to Harald!!!!!!!!!!!!
Bill
90 Westy Syncro
Lake Tahoe

Their phone number is 916-922-3487. They're a good shop. I also bought an
inexpensive water pump from them for my Westy. And they will take phone
orders and mail you the part.