Since selling our awesome Unimog last November, we have put a lot of thought into what we’d like to do next. Obviously, this coronavirus thing has totally changed our plans (like everyone else). We decided that we want another overland project and overland vehicle. This time we opted for something a little smaller that would fit in our shop at home and be primarily intended for local, short trips.
This is our “new” 1974 Pinzgauer 710M. It has portal axles with awesome ground clearance and is fully 4×4 capable with locking differentials. It needs a lot of little things in addition to the overall habitat build, but it’s a great base vehicle.
We’ll be sorting out our plan over the coming weeks with the intent of digging into the build heavily later this summer and fall.
The first line of business with our new overland build is to clean up and inspect the Pinzgauer. Overall, the truck is in quite good shape, but we gave it a good deep cleaning so we could really see what needed worked on. There is basically zero rust on the vehicle. The coatings of the original truck are really high quality. We’ve started making a long list of little things to fix, and we have been making orders on almost a daily basis to collect parts and materials for the build.
1974 Pinzgauer 710M
Front of 1974 Pinzgauer 710M
1974 Pinzgauer 710M Transfer Case
1974 Pinzgauer 710M Engine and Transmission
1974 Pinzgauer 710M Drive Train
The first priority is to fix anything on the truck that needs fixed, but we are also getting right into discussions about upgrades. Based on our experience with the Unimog, we know how small upgrades can really improve the drive-ability and general comfort of an overland vehicle. For that reason, one of the first upgrades we are doing is to install an electronic programmable VDO speedometer / odometer. The one we got is almost identical to the one we put in the Mog 2 years ago. Other than the speedometer being generally important on its own, we found having a reliable odometer is super important for range and fuel management.
We have also started looking into components to upgrade the engine to fuel injection. It would be a relatively expensive and involved upgrade, but it seems like it would really improve drive-ability, fuel economy, and emissions.
Had additional conversations with GoatWerks about fuel injection system
Installed door retaining spring and roller
Removed rifle mounts
Fixed broken tack weld on passenger door
Received composite panels
Received numerous small parts from Swiss Army Vehicles
Received composite material from Aircraft Spruce for making cab hard top
Received felt for hard top lining from McMaster-Carr
Ordered hand cable winch
We are really starting to get to know the Pinzgauer now, and we are getting into overall project planning. It’s been really helpful to receive some parts and materials to aid in the next step of design. We are also making lots of small fixes and improvements to the chassis so the truck is feeling a lot cleaner and more familiar.
New Locking Gas Cap and Seals from Swiss Army Vehicles
Composite Materials for Cab Roof
28mm Honeycomb Fiberglass Composite Panels
Gillespie Primer and Paint
New Pinzgauer Door Retaining Spring and Roller
Installed Pinzgauer Door Retaining Spring and Roller
Drained Oil to Fix Oil Leaks
New Drain Plug, Crush Washer, and Tightened Oil Pan Bolts
Original Pinzgauer Fuel Cap
New Locking Pinzgauer Fuel Cap
Cleaned Up Pinzgauer Battery Tray
Fabricating New Battery Lead
New Battery Lead
New Battery Lead Installed
Fabricating Fiberglass Battery Hold Down
Fabricating Fiberglass Battery Hold Down
Fabricating Fiberglass Battery Hold Down
Finished Fabricating Fiberglass Battery Hold Down
Installed New Pinzgauer Fiberglass Battery Hold Down
This week was another week of collecting our thoughts, getting ready to dig in, and ordering things for the Pinzgauer. The first thing we did was rearrange our shop and move our big milling machine out of our 2-car garage to give better room to work on the Pinzgauer. It’s really convenient that we can work on this project at home. We now have it set up so there is nice walking room all around the vehicle. We also rearranged some power strips and tools to make sure we have easy access to everything we need in the shop. It’s feeling very organized and we are ready to start in earnest.
We are continuing to order small parts and do little repairs to the Pinzgauer. We plan to continuously do upgrades to the chassis as we start designing and laying out the habitat for the back. During the installation of the electronic speedometer, I decided to pull apart the speedometer drive to inspect it. I had done the same thing on our Unimog as just a general inspection prior to the upgrade. Everything was squeaky clean on the Unimog, but unfortunately, the drive gear on the Pinzgauer was pretty much at the end of its life. New replacement parts are on their way.
As we are getting into sourcing materials and parts, we are finding that this COVID-19 situation is making things a little bit less available and sometimes significantly more expensive than they were a few months ago. For that reason, we have decided to just go ahead and order most things that we think we will need even if we don’t plan on using them right away. It seems better to just get them here so that they are available (or get on a waiting list sooner). It’s also kind of nice getting hardware early because we can design around actual hardware as we start to lay out our habitat.
We have a pretty nice habitat design going that we will talk about in a few weeks. From the beginning, we knew that we would have to make an adapter between the Pinzgauer cab rear frame and the habitat. The rear frame of the cab is canted forward at the top by 3 7/16″, so in preparation for finalizing our habitat design, we’ve decide to go ahead and fabricate that adapter. The timing actually works out quite well as we’d like to start making a new fiberglass cab roof soon as well.
This week, we dug into some mechanical work on the Pinzgauer. The first line of work was removing the old broken engine mounts and replacing them with fresh, new ones. The old mounts were completely fractured and the engine was unconstrained in the engine bay. Other than just being completely required, hopefully it also helps with overall drive vibration.
The next fix was replacing the speedometer pinion on the front of the differential and replacing the front differential seal. The Pinzgauer chassis is a really neat design with a centralized tube instead of a frame. It’s one of the things that gives a Pinzgauer such remarkable off-road performance, but in this case it meant that we had a lot of hardware to remove to get to the front of the differential in order to replace the pinion. To get to the speedometer pinion, you have to remove the front bumper, forward chassis structure, steering linkages, high/low cable mount, emergency brake pulley, and steering damper. Basically, the whole front end. It’s all fixed up and ready to go now. Once the new speedometer gear arrives, we can finalize the new speedometer installation. Taking the steering apart gave us a good opportunity to verify that the steering damper is healthy and happy.
Another modification was to relocate and rewire the custom reverse light. We also now have a new reverse light switch for the transmission that we will be installing soon.
New Pinzgauer Engine Mounts
Old Pinzgauer Engine Mounts
Installed New Pinzgauer Engine Mounts
Removed Pinzgauer Front Structure
Pinzgauer Front Bumper Assembly Hardware
Pinzgauer Front Differential
New and Old Pinzgauer Speedometer Pinions
Inspected Steering Damper
Pinzgauer Custom Reverse Light
We’ve continued to collect up more parts for the overall vehicle. We are happy to have our habitat entry door to design around. We really liked our military water jerry cans that we used on the Unimog, so we decided to go with the same setup on this vehicle, but we will be carrying 2 instead of the 6 that we had before. We also decided not to mount a dedicated winch to this vehicle, so we went with a cable hand winch. Having a manual winch will allow us to pull forward, backwards, or sideways, which seems like an added bonus for such a small vehicle.
Lots of small mechanical fixes and upgrades to the Pinzgauer chassis this week. We got the installation of a new electronic speedometer finished. It required doing a little bit of machine work on the speedometer gear retaining assembly, but it is all super nicely installed now. The speedometer wiring is finished and everything checks out, so it’s nice to know we will have an accurate speedometer going forward, once we get it calibrated.
While having the dash pulled apart for the speedometer installation, we had the opportunity to inspect and clean up the overall dash wiring, and install the wiring harness for a new electronic tachometer. The wiring is way cleaner now and everything under the dash is organized and secured. In the process, we ended up doing a ton of little electronic fixes (many grounding fixes, fixed wiper motor wiring, fixed faulty tail light…). An electrical upgrade that we are currently working on is adding a switch to the transmission so that the white reverse light on the back automatically illuminates when the transmission is put in reverse. While we had the dash pulled apart, we wired an extra dash light to come on when the vehicle is in reverse. We really liked that the Unimog had transmission gear indicator lights, so it will be nice to have a positive verification when putting the vehicle in reverse.
We continue to do maintenance work on the drive train. The gear shift is fairly tight for the vehicle’s age, but a lot of the little linkage bushings and bearings are worn, so we are replacing all of them. The shifting is getting a lot tighter with each improvement. We also started replacing the transfer case input seal that had been leaking. The truck has been super easy to work on. Sometimes we have to hop on the lathe to true up a part or fix a little damage from previous mechanics.
We are making many little random fixes as we work through everything. We replaced the passenger side window securing strap and probably a half dozen other things we are forgetting to mention here.
Wired Electronic Speedometer for Pinzgauer Ready to Install
Pinzgauer Speedometer Gears
Turning Pinzgauer Speedometer Gear Housing
Pinzgauer Electronic Speedometer Sender Assembly
Rewiring Pinzgauer Dash Electronics
New Wiring for Pinzgauer Electronic Tachometer
Pinzgauer Transmission Shift Linkages
Setting Length of Pinzgauer Transmission Linkage
Installed New Pinzgauer Shift Linkage
Pinzgauer Transmission Access
Pinzgauer Transfer Case Seal Replacement
Cleaning up Bore of Pinzgauer Transfer Case Input Seal Housing
Pinzgauer Transfer Case Input Seal Housing Assembly
Pinzgauer Window Closure Strap
Pinzgauer Window Closure Strap
Fixed Pinzgauer Wiper Motor
We are finding that some decisions are a lot easier to make on this project because of our experience building and using the Unimog. This time we are just immediately picking some of the same components that we spent a lot of time researching previously. This week we got an awesome shipment from Total Composites (now selling products as Expedition Upfitter), with a Planar diesel heater, 2 Eurovision Tern Overland windows, and a box of Korapop 225 adhesive. We also picked up a set of matching key padlocks for the exterior vehicle storage. On the Unimog, we really liked having all the padlocks common keyed, so we decided to do that again.
I feel like our blog posts for the next little while are going to start with, “This week we made good mechanical progress on the Pinzgauer.” It’s totally true, and the reality is that right now we are mostly putting effort into making the Pinzgauer mechanically sound and as reliable as we can.
This week, we focused on finishing the transfer case installation and we finished the complete refurbishment of the shift assembly. Now, every bearing and bushing between the gear shift and the transmission have been replaced. Shifting is nice and tight now, and it feels quite a bit different. When we removed the gear shift assembly, we discovered that the reverse indent pin that controls the shift pattern to get into reverse was completely missing. Apparently at some point in the truck’s life, the pin had somehow fallen out. It was previously really hard to get into reverse, so now that makes sense. I fabricated a new pin out of a tool steel dowel pin and re-reamed the installation hole for a press fit. Luckily, the parts manual has specific sizes of the components, so it was pretty easy to get right. Shifting into reverse is really positive now and you can’t get into reverse by accident.
I also finalized the installation of the reverse indicator switch for the reverse light. The switch works well but required putting the transmission in and out of reverse a bunch of times to break in all the parts. It seems to work well, though.
At the end of the week, we also started another few small things like replacing all the dash vibrex mount fasteners. They are a clever design that uses an expanding rubber plug to quickly secure the dash panel without vibration. All the old rubber had fallen apart years ago. There are 7 of them on the dash assembly, so it was nice to get them fixed up. The lead in work for next week is that I started fabricating and fit checking parts for the cab to habitat adapter. It will be a lot of work, but seems to be going together well.
Making Pinzgauer Transfer Case Seal Installation Tool
Pinzgauer Transfer Case Seal Installation Tool
Reassembling Pinzgauer Transfer Case Input Seal
Pinzgauer Reverse Light Switch and Plunger
Pinzgauer Reverse Light Switch Installed
Pinzgauer Shift Assembly Before Rebuild
Pinzgauer Shift Stick Rebuild Components
Reaming Pinzgauer Reverse Indent Pin
Assembled Pinzgauer Reverse Indent Pin
Finished Rebuilt Pinzgauer Stick Shift Assembly
Pinzgauer Dash Vibrex Fastener
Started Making Components for Cab to Habitat Adapter
Surprisingly, it’s been a month since we last posted. We have actually been working behind the scenes, but haven’t had a lot to share. We have been working hard to get the custom cab roof made. We will share more about that in the next few weeks. The cab roof isn’t very interesting to share in real time as it is just evening after evening of fiberglass work and sanding.
We did complete the fabrication and installation of the custom stainless steel rear exit exhaust system this weekend. It turned out great. It’s all completely sealed with zero leaks. We think the rear exit will really help minimize exhaust smell.
Exhaust System Seal Hardware
Exhaust Heat Exchanger Air Heater Ducts
Fabricated Stainless Steel Exhaust Hanger
Cutting Tube Bends for Exhaust Pipe
Welding Exhaust Pipe
Finished Custom Exhaust Pipe
Step Drilling Hole for Oxygen Sensor Bung
O2 Sensor Bung Ready to Weld in Muffler
Welding O2 Sensor Bung
Completed Stainless Steel Exhaust System Ready to Install
The old muffler system was original to the truck from 1974. It had actually held up pretty well, but it had developed some pretty serious exhaust leaks. It was also driver side exit, like most military convoy vehicles. We had that same arrangement on our 1943 GPW, LMTV, and our Unimog. It works fine, but we never liked that it blows exhaust directly on people that are talking to you through the driver side window. Last summer, our Unimog side exhaust seemed to really annoy border crossing agents. We also don’t like the smell of gasoline engine exhaust at all. Somehow we have a lot more tolerance for diesel engine exhaust smell. Long story short, we decided to have a more conventional exhaust layout and fabricated a custom stainless steel exhaust duct to deliver the exhaust just past the rear bumper.
For the last few weeks, we have been working hard making a composite hardtop for the Pinzgauer cab. We finally finished all the composite work and trimmed it this weekend, so we wanted to share the process sequence. It still needs painted before final installation, but it’s basically finished.
We started out by bonding a stack of extruded polystyrene foam into a large rectangular block the size of the roof. We then spent a lot of time carving, sanding, and sculpting the foam into the desired roof shape. We then released it with masking tape and packing tape so that the composite would not stick to the form plug.
The composite layup is 6 ounce woven fiberglass cloth and 4 ounce woven Kevlar cloth in epoxy resin. After all the plies were stacked, wet out, and cured, the roof was body worked and primed before being removed from the truck. After trimming away excess composite material, the roof fits very nicely on the cab. Overall we are really happy with the process and it will be a great improvement over the canvas top.
Making Custom Pinzgauer Cab Hardtop – Styrofoam Form Plug
Making Custom Pinzgauer Cab Hardtop – Finished and Shaped Plug
Making Custom Pinzgauer Cab Hardtop – Released Plug and Masked
Making Custom Pinzgauer Cab Hardtop – Dry Fitting Fiberglass Cloth
Making Custom Pinzgauer Cab Hardtop – Epoxy Saturated Fiberglass and Kevlar
Making Custom Pinzgauer Cab Hardtop – Finished Bodyworking and Primed
Making Custom Pinzgauer Cab Hardtop – Removed and Ready for Trim
Making Custom Pinzgauer Cab Hardtop – Final Trimmed
Making Custom Pinzgauer Cab Hardtop – Final Fit Check
We intend to keep as much of the Pinzgauer body as stock as possible, but we did need to fabricate an adapter for the B Pillar assembly on the back of the cab so that there was a nice, flat, vertical surface to interface with the future habitat. It’s also nice because because it adds a little bit of a beef up to the nearly nonexistent Pinzgauer roll bar.
Welding B Pillar to Habitat Adapter
Finished B Pillar to Habitat Adapter
Pinzgauer B Pillar to Habitat Adapter Final Painted
We added the finishing touches to the custom cab hardtop this week. The outside got a nice, glossy coat of white paint and we put speckled texture paint on the inside surface. It looks really sharp. On previous projects, we have really liked using 1/2″ thick wool felt as a headliner material. After cutting the felt to a pleasing shape, we bonded it to the underside of the hardtop using urethane adhesive. It should make a big improvement on temperature and noise in the cab.
Custom Pinzguaer Hardtop Final Painted
Wool Felt For Custom Pinzguaer Hardtop
Bonding Felt Headliner to Custom Pinzguaer Hardtop
Textured Paint on Inside of Custom Pinzguaer Hardtop
We also did a few small general upgrades. We installed the new electronic tachometer and fit checked the new engine cover. It all looked good.