>How about the earlier Kombi's.  My old 72 bus, the door used to come right
>off.  The 72 I have now will get to that stage too I suppose.  I think it
>may be the plastic thing that goes on the runner!!!  Is that the right
>conclusion???

My '71,'72 and '75 all had two steel bearings, one the served as the load 
carrier, rolling in the bottom of the door track. The other was horizontal, 
and kept the door bracket within the track guides, just under the top of the 
door track. This area gets full of grit, rusts down, and the bearings seize 
then self destruct. The are replaceable, but not via the dealer, who sells a 
new bottom bracket. If the wheels are seized/missing, the door wears and 
falls out readily. Take off the bracket, an Allen key is needed, then try to 
get the bearings off. They're held in by circlips, under plastic caps if 
they are still there. Else by rust. Get the remains and the bracket to a 
bearing supplier and say gimme two like these. They'll usually match you up 
close enough. <$10.00 for both. Check your bracket for corrosion pocks, I 
had one break of completely, not while driving though. We see a LOT of salt 
here in winter.    tim s.