I remember using about 24 feet of the stuff. I did the hoses going up to
the rear heater too. If you have a older watercooled vanagon, that 5/8 inch
hose will leak cus of the metal tees. However, there seems to be no other
choice, as I bought the 5/8 inch hose at a foreign car auto parts place
(metric stuff sold there).

 The connector tee is metal in the older vanagons. It is plastic and a bit
thicker in diameter in the later vanagons. Get 2 of these plactic tees and
you will be ok. BD will sell you these(thanks for the parts,fast
shipping!) , or you can slash them from a post 85(cover your eyes first). I
think these plastic tees are another change from the early and late 85
vanaogns, as my  early 85 westy had the metal tees , and the late 85 parts
vanagon I have, had the plastic tees. I say had, as they now reside in the
early 85.

The 5/8 inch hose tightens up to the rear seat heater outlets, just
fine.The 5/8 inch hose will have a problem passing throught the rubber
gromets that go between in the metal body between the engine compartment
and seat area.Get some soap and start struggeling,and they will go through.