Ok, 40 years or older VW Bug that is hard starting hot. Driving for any length of time allows the chassis to heat up and expand. In some cases it also has an effect on the start system where in sufficient ground is not being provided to the starter until the chassis cools and contracts enough to allow ground. What clears up this problem is to connect 2, 10 gauge wires from the negative battery post to the bottom starter mount stud. Clean the contact surface, and with ring connectors large enough to fit over the 10mm stud, install the wires on the stud, replace the nut with a washer and secure it. This will cure many hard start hot maladies, BUT, not all. There are other methods to get around this particular problem. Will deal with them later if there is a need.  Ainokea       

From what you describe it might not be just a ground problem. It could be a faulty ignition switch or maybe resistance in circuit # 30 wiring to the ignition switch that does not provide enough current to terminal # 50 to turn the starter. I would first check the ignition switch for functionality. I do not know the year of your bus so don't know the type of switch you have. But, your trick with the wrench points to the ignition switch. Ainokea

That was my thought with the hot start relay. I have a relay that looks identical to the one you linked to, just haven't done it.

As for the ignition switch, I believe it is working because I turn it to "ON" and the idiot lights come on. Then I turn to "START" and they dim down a little bit, which makes me think that the switch is responding to the change, but there's not enough current getting to the starter. Plus, once it gets jumped like I described, the key works fine for a while.

I'll try the relay and report back. If it works, then we will have solved it. If it doesn't, I'll invest in another 14mm wrench!

In case no one noticed, the post originally related to a type 1 Bug and not to the type II. The assumption is in fact correct that insufficient current is reaching terminal 50 on the starter when the key is turned. In many cases this can be remedied by removing all the fuses, cleaning all the contacts with a small wire brush, tightening the fuse contacts, and fitting new or cleaned up fuses. This simply eliminates all or some of the resistance in the start circuit and may cure some no start situations. A big problem with all VW's is the power circuit # 30 comes from a regulated source, then goes to the light switch, then to the fuse panel, and finally to the ignition switch. When the key is turned to start, the ignition switch powers up circuit # 15, coil and ignition, then sends power to terminal # 50 on the starter. Without enough current reaching the starter, the result is no start. One solution is to cut off the ignition switch power from the fuse panel and run a single strand of 10 gauge from the positive battery terminal directly to # 30 on the ignition switch. On type 1 and 3, it's very much easier than on a bus because of the length and it can be done inside the vehicle not underneath. consequently, a hot start relay does make sense unless you're a VW diehard like me. Ainokea       

This is probably a problem that is unique to 74 and 75 Type 1s with the seat belt interlock system . . . I'm not sure exactly when they started and ended, but I've had a 74 Super and 75 Super Convertible that had the system and I've never seen it on a 73 or 76.  Anyway, they apparently had a sensor in the front seats and a switch in the seat belts.  If someone was sitting in the seat, that belt had to be buckled to engage a relay in the fuse box that was in line with the main power to the switch.  Of course after a few years the seat sensors went bad and the whole system became a big headache.  The common fix back in the day seems to have been pulling out the relay and wrapping wire around the two big terminals then plugging it back in.  But after a few years, the wires corrode and start losing contact . . . sometimes it would start, sometimes it wouldn't do anything.  After a year or so of pulling my hair out I figured out the problem and cut the power wires going into and out of the relay, cut out about a foot of wire, soldered them together and insulated them with heat shrink tubing.  Problem solved.

What ainokea said about cleaning the fuses and connections is good advice for ANY electrical issue on an old VW.  When I bought my Dasher from Rick, I had one dim headlight on one side, one bright on the other, no dash lights or dome light and one tail light.  I cleaned the fuses and EVERYTHING, including the radio started working.  Once you get 'em clean, dielectric grease is your best friend!  It will keep moisture in the air away from the connection and hold off new corrosion for years to come.

A lot of people simply connected the belts and left them on the seat.

A lot of the newer fork lifts we use at work have a seat belt interlock system.  A lot of people would do the same thing, just buckle the seat belt and sit on top of it.  We bought three new Linde brand trucks a while back and their seat belt interlock system required weight on the seat first and then fastening the seat belt.  If you buckle the belt first, the truck won't start.  It's hard for the operator to bypass that system.

Some Rabbits that had the seatbelt connected to the door to complete the start circuit ground, it would quit when the wires between the door and it's front jam would break resulting in a frustrating no start situation.You'd have to cut open or pull the rubber sleeve to access the break to repair. Anyone remember that? Ainokea