Building the Volkshauler

[boulderz]

Not a VW, but period correct inspiration..My favorite vintage car hauler: Lancia Super Jolly

[Gregory Campbell]

[Gregory Campbell]

It looks like I can get about 4.5" of travel with the rear suspension. This seems pretty good although I wish it would drop a little more for unloading. With my 23" dia. rear tires I still have about 2" before the tire hits the inner fender. I may try and tweak this later on in the build.

I worked on the tag axle today. I had an extra bit of a rear frame and torsion tube to work with. This will be spliced in backwards behind the other torsion tube and frame.

Cut off the rusty floor and other sheet metal and cross bars. Also cut off the shock mounts and bump stops and horns. Welded on the new horns. Won't know till later but it looks like the horns might work as a basis for my rear engine mount.

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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

Got my new rear tires today. 205-50-15. I wanted a pretty small tire to keep my gear ratio low. I have a 901 5 speed and one of the issues with this transmission is that the first gears are a little too tall. 5th gears can be interchanged but the typical 5th is also too tall. There is a special 1 year only 912 6:29 ring and pinion which I am also using. Hopefully this will all make that uphill start with a fully loaded truck do-able.

Had to machine the rear hub slightly to fit the 911 brake rotor.

Did a trial fit to ensure my plan for the 7" American Racing Wheel would work. Looks like it should just fit inside the fender!

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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[squareweave]

Looking good. What is the reason to run the rear hub upside down?

[Gregory Campbell]

The rear hub is from a Bay Bus. It is run upside down to get the stock shock mount out of the way of the air bag mount. The new lower shock mount is the hole in the "bag" arm that is closer to the axle. The old shock mount is now redundant but apparently it weakens the assembly if you cut it off.

I have not been posting much in the last few days because I have just been sand blasting prior to welding the frame back together. Nothing too interesting to show when you are sandblasting!
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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

Working on getting the cab ready for blasting. It hurt to cut up a good dash but I am going to put four 52mm gauges in the dash. Two to the left of the speedo and two to the right. I cut some of the radio grills out and will replace with solid metal and then cut the gauge holes. Looking forward to when my work goes from destructive to constructive.

Made a dolly to take the cab out to the sand pit.

_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

As mentioned earlier, I decided on air suspension. This would give me a way to deal with a vehicle weight which would potentially double when fully loaded. I would also help with the loading and unloading because I could lower the rear and raise in front to lower the deck height and increase the loading angle. Air suspension is pretty new to me. My only experience was with an old front wheel drive GMC Motorhome which had tandem axles with airbags in the rear. It worked well but had no fancy controls. It had a 3 position switch; full pressure, travel pressure and no pressure. My recent homework on air systems suggested that the best way to control the bags is with ride height sensors. These systems have sophisticated computer controls to maintain ride height under various conditions. But I had 3 concerns around the tag axle; maintaining drive traction under all conditions, dealing with manoeverability due to the tag axle dragging in tight turns, and ensuring braking grip under all conditions.

The solution I came up with was a “conventional” ride height controlled system for the steering and drive axles and a pressure sensitive system for the tag axle. The idea is to set the tag axle to approximately 20% of the drive axle pressure when there is no load. When the vehicle is loaded the drive axle would be set at 80% of drive axle pressure. I would be able to vary these tag axle percentages as I learn how the vehicle handles.

I also decided only to put brakes on the steering and drive axles and not the tag axle.

Here is a table to check how this idea works under various conditions:

As I said this is all pretty new to me so if any of you have advice I will gladly receive it. And its not to late yet because I have not purchased or installed the control system.

Thanks for following along.
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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[BarryL]

In my opinion it appears you have thought it through. I know the GMC vehicle you are referring to.

[Gregory Campbell]

I though I would provide a bit more details on a couple of the design decisions.

WHY A TANDEM?
As touched on earlier I decided on the tag axle idea because of the aesthetics and load carrying capability . I drew up a bunch of scale drawings with different amounts of stretch and different axle configurations. A bus with a 4’ stretch with just one rear axle looks a little too lanky. I know it might sound crazy to design suspension around aesthetics but I believe in the philosophy that its got to "look right to be right". The other big factor was payload. If you are using low profile tires the load rating is only around 1000 lbs per tire. I am planning on a GVW of around 5000lbs so the truck will easily exceed the tire rating if there is only 4 tires. I need low profile tires in the front to be able to lower the bus without tubbing and having low profile tires in the front and tall tires in the rear wouldn't look right. In addition I would not be able to lower the rear (with the air bags) for unloading because tall rear tires would hit the top of the inner fenders. So tandem axle was the solution.

HOW TO BUILD THE TAG AXLE?
The next question is how to configure the tag axle suspension. I have seen quite a few pictures of tandem axle split buses but I don't know how any of them built the suspension. One of the design premises is that as much as possible should be VW or Porsche parts. This was to have a consistent theme but also to use parts which I have and or parts that I am familiar with. A swing axle wasn’t going to work without using a dummy transmission, which seemed impractical. I am not familiar with any solid axle designs or parts so that was out. So it would have to be some kind of IRS. If the tag axle was in the regular orientation then the separation between the tag and the drive axle would be too great. So….why not invert it like Porsche #1? Seems like it should work! All I would have to do was get a second rear frame complete with torsion tube, convert to IRS and weld it in! I hope to be splicing the frame together in a couple weeks.
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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

On the way to the sand pit.

playing in the sand.

_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Jeler]

Interesting thread, thanks.

Here's a short video from Wolfgangs flat bed.

https://www.youtube.com/watch?v=ry_1XjGZHnQ

[Gregory Campbell]

Thanks for sharing that Jeler. Nice to see it in action. There have been a few single cabs built that way. Pretty cool.
_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

Made some exciting progress today splicing the 2 rear frames together. It took a lot of measuring and aligning to get my desired distance between the torsion tubes. I calculated what it would take to give a net distance of 4" between the rear tires. The process was greatly complicated because the rear frame is not originally parallel to the vehicle. It gets wider as you go rearward. So in my case with the tag axle being reversed the frame gets wider up till halfway between the rear axles and then it gets narrower as you go rearward. To further complicate the alignment the frame swoops up to provide clearance for the axles , then back down, then up again for the tag axle, then down but not to the same height as forward of the front torsion tube!

The other issue I had to overcome was that my second rear frame (the one for the tag axle) was not as long as I needed. To span this gap I used the reinforcing plates provided by Creative Engineering to support the air bags. This all worked pretty good but I made me a bit uneasy with all the funny angles.

I felt really good being putting things together after so much destruction in the first phases of the project.

This picture shows the 2 waves in the frame with the rear on the left and the front on the right.

This picture is taken from the rear looking forward.

_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

I am getting ready to go to LA for the Porsche Lit and swap meet next weekend. I thought I had better review my parts needs before I went to the swap meet.

Upon review of all my planned switches and gauges I realized that 2 of the switches I am planning should really be "normally closed" instead of the "normally open" that all split busses have. Specifically I am looking for an ignition switch (to turn off the coil) and a fuel pump switch. These are nice to have for maintenance or testing systems. And all Porsches Carreras had ignition switches so that has got to be cool! I want all the switches to be original looking switches so that was the challenge.

I took a stock wiper switch apart and stared at it for awhile. It looked like if I used a dremel to grind the rivet on the end of the stud then I could flip the brass contact. The next step was to clean up the stud shaft on a mini-lathe. Then drill out the end with a #50 drill. Then tap with 2-56 threads then put it all back together with a loctited bolt. Voila now the switch is normally closed. It all worked really well.

Sorry I do not have more photos I got carried away once I started and didn't stop to document the procedure. No one else will probably want to do this obscure little project but If anyone has questions I can provide more details.
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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Chip]

I hear you ran into my old man at a Porsche event in LA last weekend. Glad to hear you two were able to bump into each other. Progress is looking great!

[Gregory Campbell]

Hi Chip,

Yes, had a great conversation with your Dad. Too bad it didn't work out to bring his Stretched single cab hauler. Would have been really cool to see with his 904.

I need to get back to building mine. Now that I am inspired following my trip to LA and Sand Diego for all things Porsche.
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'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[Gregory Campbell]

Hi Chip,

Yes, had a great conversation with your Dad. Too bad it didn't work out to bring his Stretched single cab hauler. Would have been really cool to see with his 904.

I need to get back to building mine. Now that I am inspired following my trip to LA and Sand Diego for all things Porsche.
_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches

[panel]

See this ?

https://www.thesamba.com/vw/classifieds/detail.php...id=2533904

https://drive.google.com/drive/folders/1m_98GjNVRBehji6_0SEhcSWQWDvu-58C
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My '65-Subaru EJ20 Turbo conversion

[Gregory Campbell]

thanks Panel. Looks interesting. I wish there were more details.
_________________
'62 Volkshauler (current project)
'57 Ghia, Porschized Rally Car (future project)
'67 Double Cab, Porschwagen
bunch of other old Porsches