WabiSabi Overland Expedition Truck
Wabi-Sabi Overland Expedition Truck

We have often enjoyed the places that 4-wheel drive vehicles can take us. We realized recently that we have owned 8 different 4x4s. Our current expedition vehicle is a 1987 Mercedes Benz 435 U1300L chassis with a custom composite sandwich habitat module that we designed and built.

As we are both design engineers and have a lot of fabrication experience, we designed and built the truck ourselves. We spent a lot of time early in the project sketching, mocking up, CAD modeling, and designing all the components of the truck prior to starting fabrication.

Prior to building our habitat module, we spent a lot of time upgrading our base truck and modifying it for the habitat interface. The truck upgrade process was a significant portion of our project time. The modifications greatly improved the truck’s drive-ability, comfort, and highway performance. In addition to general mechanical upgrades, we fabricated a custom habitat subframe using parts of the original Mercedes Benz 4-point subframe. We also removed the cab rear windows and installed a custom passthrough door from the cab into the habitat. We totally redid the interior of the cab with insulation, sound deadening, and suspension seats.

We built our habitat module using panels and corner extrusions supplied by Total Composites.  Total Composites was able to supply us with lightweight, insulated composite sandwich panels that were cut to our blueprints. We assembled the habitat box using urethane adhesives. The construction and bonding of the box is such that there is no cold bridging in the structure of the assembly. We had integrated hardpoints installed the sandwich panels for mounting to the truck subframe and for mounting the spare tire assembly on the back of the habitat. During habitat assembly, we ran most of the habitat wiring inside the panels and extrusions to produce a clean, durable, and long-lasting systems installation.

A lot of the time spent designing the truck was centered around the layout and comfort of the habitat interior. Because the truck is designed for long duration travel, we didn’t want it to seem like camping. Early in the project we made a list of things that we thought were necessary for being comfortable traveling for a long duration: a permanent bed, comfortable eating area, good standing height / head clearance, a dry dry bath with separate shower, etc. In addition to basic comfort, we also wanted the interior to aesthetically pleasing, bright, and cozy. The habitat interior took a significant amount of time because we had to custom build almost everything.

Integration of systems in the truck spanned the entire project. Sourcing parts and making sure that everything fit together well took a lot of effort through all the phases of the project. Some seemingly simple things like the entry ladder took several iterations to get right, while other seemingly complicated things like the solar charging system have worked well from the beginning. There are simply too many detailed systems topics to do justice in a quick summary paragraph; for more information, see the below specifications.

The truck is super comfortable and lets us get off the beaten path.

Truck Specs

  • 1987 Mercedes Benz 435 (U1300L)
  • Exterior Dimensions (including habitat):
    • 20’11” (251″) [6.38 m] long
    • 7’6.5″ (90.5″) [2.30 m] wide
    • 11’6.25″ (138.25″) [3.51 m] tall
  • Engine: OM366A (170 hp turbocharged engine)
  • Truck comfortably cruises at 60mph
  • Upgraded fuel primer pump
  • Digital exhaust gas temperature gauge on turbo
  • Tires: Continental MPT 81 365/80R20 (5x) with Dyna balancing beads
  • Sandblasted and powdercoated steel rims
  • Fast gear ratio axles
  • Synthetic fluids in hubs, axles, and transmission
  • Block Pre-Heater: Webasto Thermo Top C Diesel Heater 12V 5KW 1311551A
  • 24V electrical system
  • Battery: NAPA BAT 7256 Size: 6TL, (2x)
  • Winch: Superwinch EP 16.5, 16,500lb 24V
  • 2 steel WWII Marston mat sand ladders, sandblasted and powdercoated
  • Custom steel Roof Rack
  • Custom steel roof rack access ladders mounted on cab sides.
  • 2-inch tow receiver in front (with shackle fitting)
  • 5-inch tow receiver in rear (with pintle fitting)
  • Reverse camera
  • Downward facing mirror on passenger side
  • Programable dual unit VDO electronic speedometer
  • LED marker lights
  • LED cab interior light
  • Stereo system with USB input and SiriusXM radio
  • Higher wattage headlights
  • High wattage LED fog / trail lights
  • High volume upgraded front portal hub tanks
  • Regulated auxiliary compressed air take-off on truck pneumatic system
  • ARB electric air compressor for pre-charging truck pneumatic system
  • Driver and passenger mechanical suspension seats
  • Dynamat sound insulation in cab
  • Cab acoustic insulation
  • Atkinson-Vos sound deadening floor mats
  • Locking cab to habitat passthrough door
  • Matching ignition and cab door keys
  • Custom rear bumper with integrated mud/rock flaps

Fluid Tanks

  • Stock U1300L fuel tank
  • 4 20L Jerry can (mounted under habitat)
  • 18-gallon gray water tank (mounted under habitat)
  • 30-gallon fresh water capacity (in 6 military Jerry cans stowed inside)
  • Airhead composting toilet

Storage

  • 4 removable steel storage lockers/boxes mounted under habitat
  • 2 aluminum military foot lockers mounted on roof rack
  • Large storage areas under bed accessible through locking side hatches
  • Large quantities of cabinet storage inside habitat

Habitat Specs

  • Exterior Dimensions: 137″ long, 86.5″ wide, 83″ tall
  • Interior Dimensions: 82.5″ wide with 6’4″ standing head height
  • Walls are 50mm thick fiberglass composite sandwich panel.
  • The ceiling, floor, forward, and aft wall are 84mm thick fiberglass composite sandwich panel
  • Steel / composite hardpoints embedded in floor and back wall for mounting
  • Habitat is mounted to modified Mercedes torsion free subframe
  • Euro-style double glazed windows and large roof hatch (with integrated blinds and screens)
  • Euro-style door with integrated blind and accordion screen
  • Locking cargo access hatches with matching door key
  • Accordion seal to cab passthrough
  • ARB awning on passenger side of habitat
  • Entry door grab handles
  • Custom lockable folding habitat entry ladder (stows in shower)
  • Custom lockable non-folding habit entry ladder

Habitat Interior

  • Entry shower with draining floor (to gray water tank) doubles as mudroom
  • Dry bath with storage, mirror, and towel racks
  • Fantastic fan vent over dry bath
  • Dometic alcohol stove
  • Stainless steel sink that drains to gray water tank
  • General Ecology Seagull water filtration system
  • Sureflow electric water pump, accumulator, and prefilter
  • Oak kitchen countertop with slide out cutting board
  • Overhead kitchen cabinets, pantry, and under counter drawers and storage
  • Dometic CFX-40 compressor chest refrigerator with under bed slideout
  • 115V ground fault outlet in kitchen with USB charging
  • Antique 48” x 75” Mattress Insider memory foam mattress
  • Froli star ventilated box springs under mattress
  • Overbed steel clothing cabinets
  • Headboard with storage cubbies
  • 115V ground fault power strip in bed area
  • Caframo Sirocco II fan over bed
  • 2 small windows above bed for good cross ventilation
  • Oak table in dinette
  • Dinette seats 2 comfortably, 4 in a pinch
  • Dinette is at same height as countertop for additional counter space
  • Storage under dinette seats; aft storage for water
  • Over dinette cabinets
  • 115V ground fault power strip under table

Lighting

  • LED lighting throughout habitat interior
  • Strip light over kitchen counter
  • Strip light over dinette
  • Lights around main hatch
  • Interior entry light
  • Spotlight over dinette
  • 2 reading lights over bed
  • Lights in storage area underneath bed
  • Exterior LED lights underneath habitat

Electrical System

  • 600 Watts rigid solar panels on roof of habitat
  • Solar panels are each fuse protected
  • Victron solar charge controller
  • Solar and main power marine grade cutoff switches
  • Battleborn Lithium Iron Phosphate batteries (300 amp-hours)
  • Victron battery monitoring system
  • 20 circuit distribution panel
  • 20 circuit switch/breaker panel (using aircraft hardware)
  • Victron 350W pure sine wave inverter
  • External shore power plug
  • 12V power supply for shore power

Habitat Systems

  • Planar 2D diesel air heater
  • Air circulation fans ducted behind cabinets and under bed
  • Heatso calorifier with integrated engine heat exchanger (not installed)

Previous Vehicle Projects

We have previous experience restoring and upgrading several other vehicles. For more information on previous vehicles, see:

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