Does it knock while braking?  The "knocking" that I've heard under my 
vanagon was rear brake related.  It was quite pronounced when braking 
while backing up out of the drive, but did occur at times while coming to a 
forward stop.

Karl
88 GL (looks just like Joel Walker's)

I inherited an 83 Westy, air-cooled, usa-can model from my father six years
ago. It is a wonderful vehicle. But for two or three years now, it has a
knock coming from the rear, and seemingly more from the left rear. I have had
two mechanics check out a wheel bearing or cv failure, but they both said
they were o.k. It has 68,000 miles. Sometimes I will drive it 20 miles and
not hear it, then another trip will bring out the knock, which seems louder
under load. Turning right or left does not seem to make a difference in the
sound. 
Any suggestions to help me find and correct this will be greatly appreciated.
Bob in Orlando
1953 International pick-up (not for sale)
 1997 Honda Valkyrie (for sale)
 1993 Harley-Davidson full dresser (for sale)