Mike, you should not have to slam your slider. Yes, these doors are a
pita! I have only owned one Vanagon with no slider problem. However, I
have never failed in repairing the problem. All the answers you have
gotten are good advice, but, unless I missed it (and I am kind of blind)
all are missing Step 1....that is, follow the slider door adjustment
procedure in the Bentley (this is an easy step which is adequately
described by Bentley.)This is the procedure that describes adjusting the
door so it is square with the rest of the body. Also, adjust the
stationary striker that the rear latches to (this rear latch may be worn
beyond repair, though I have had success with a bit of filing here and
there.)Follow all the lubrication advice and keep that lower track clean.
Happy Camping! Miguel