I've got an '81 Vanagon with hot start problems.  Cold, it starts fine.
Warm it cranks slowly.  Summer, highway hot the starter won't crank at all.
Wait 15 minutes and she jumps right on.  

The battery is good, I've replace the starter with a Bosch factory-rebuild,
replaced the starter switch.  Cables and grounds seem good.

The VW dealer in Yakima (WA) says they know there's a "hot start" problem.
They'll add a Ford solenoid to the Bosch which is supposed to increase the
power somehow.  They'll do this for $150, I might add.  A VW mechanic here
(Ellensburg, WA) says he's heard of such, but thinks that there's an
inherent problem in that Bosch starter such that as the wiring gets old and
resistance increases, the Bosch won't hack it anymore.  He's the one, by the
way, who replaced the starter and advised me to replace the switch, all to
no avail.  

I dunno.  It all sounds like so much double talk to me.  Never have heard of
such a thing.

In any event, has anyone out there ever run into this problem?  Is it
discussed in the archives anywhere?  Would appreciate any kind words.

Charlie