Thread: Progress on My Unimog

100% Unimog underneath, chassis lengthened. Engine in original spot. A KW is 'Cab over engine' and it is a lot easier to hide a 180hp Benz motor than a 650hp Cat, in fact the normally huge engine cover between the seats has been reduced in size. Camper body is made from freezer van type composite honeycomb wall panel called 'Monopan', built without a frame so really light weight. The body is mounted on a centre spine to allow the chassis to flex underneath. Weighs only 7.5t dry, 9t with liquids/people/stuff. Can cruise at 105k but nicer at 80-90k where you get 19 litres per 100k.

Thanks - any chance of some photos, I would love to see the engineering that's cone into that monster. Which Unimog was it based on - the wheels looks like six bolt so that would be a U1300/U1450 at the most.

Originally Posted by Capstan

100% Unimog underneath, chassis lengthened. Engine in original spot. A KW is 'Cab over engine' and it is a lot easier to hide a 180hp Benz motor than a 650hp Cat, in fact the normally huge engine cover between the seats has been reduced in size. Camper body is made from freezer van type composite honeycomb wall panel called 'Monopan', built without a frame so really light weight. The body is mounted on a centre spine to allow the chassis to flex underneath. Weighs only 7.5t dry, 9t with liquids/people/stuff. Can cruise at 105k but nicer at 80-90k where you get 19 litres per 100k.

Originally Posted by JohnF

Friend of mine, previously our RFS bush fire brigade captain reckons the Unimog would make a great unstoppable fire truck

Most rural fire brigades in Europe use them - one of the main markets for Unimogs after the military.

Yes but not in our area where we could use something like that, John.

Time for an update on the Mog progress. I have borrowed a cab tilter from a a forum member - I have it until early in January, so I need to get everything done that needs the cab tilted. I will also take a few measurements on the lifting cylinder at various extensions to see how long to make a single ram cylinder.

There is plenty of clearance for the turbo - I'll tilt the cab again and fit the heat shields and a bit more sound insulation. I will also fit up the accelerator pedal and the hand throttle linkages.

I also re-fitted the inner fenders - both refurbished with new home made rubber seals. I also fitted up the power steering reservoir and the steel lines. I have a new hose for the lower return line, but I need to get another two hoses for the upper return line, and the upper supply line. Then that should last for another 25 years.

It looks like there should be plenty of space for the inter cooler - there is 400mm of clear space between the turbo and the power steering reservoir, or if I put it up higher, I have around 700mm to the inlet manifold - I'm sure I can make something work there.

The air tanks also fit quite nicely - glad this time I managed to get all the measurement right. I have charged up the air system, and everything works. I also discovered a design error with the way I plumbed in the wet tank. When the tanks get to max pressure, the divertor valve opens and the compressor goes into free-wheel mode - which means that the wet tank would fully discharge out of the divertor valve - which is not a good idea as when the tanks get discharged, before the compressor would would be recharging the main tanks, it would have to first have to charge up the wet tank. I found this out the hard way - when I adjusted my shop compressor to go about 8.3 bar ( I have two of them rigged up in parallel to speed up the process) when the divertor valve opened - it shot the little silencer off the bottom of the valve, and discharged the entire contents of both 50lt compressor tanks, the wet and and the purge tanks - made on hell of a racket doing so. Anyway, at least I know the divertor valve works.

I have returned to fabricating the camper box again. First the battery box and the box for the diesel heater. I have fitted them both below the floor, and will have two hatches to access them. Another forum member will be making the composite floor - made from 2mm aluminium, 6mm fo foam and 4mm of ply, all vacuum bagged together to make a strong composite floor. I have to make a template out of plywood for each section of the floor - being a civil engineer, tolerances of a centimetre or so are normally pretty good, but here I need to get with a few millimetres. The panels will be quite complicated, as I have to fit around all the bracing and have the joints all hidden. The final wall on part of the floor will most likely be teak.

The main fabrication work this weekend was the two rear seats. It took a fair bit of fitting and engineering, but eventually I figured out how to make it all work. The back part of the seat still reclines using the original electric motors, and the lumbar support still works as well. The seat base is fixed to the frame, and that took a fair bit figuring out. It has to be fairly strong to be able to hold the seat belts.

The space behind the seat back is quite large - should be useful for storing some softer item that don't get used that often. The only way to access the storage will be to wind the seat back right forward. I'll test it out once I get everything sorted. I'll work on it over the next few evenings.

I finished the first seat, but ran out of steel for the second one. Since I've figured out the way to do it, the second one should take less time. Trish has tested the seat, and reckons it will work well - she could see out of the front window and the passenger side window quite easily, and the height was just right for her. I found that the angle in the first seat was a not right for me, I would get a sore neck, but the second seat works a lot better. Anyway, I would not be the one using those seats whilst driving - my seat is the one behind the steering wheel.

Loads of progress over the past month. I decided to find out how much the truck weighs - it has always been one of those things that have been in the back of my mind - what if it is overweight - after all the effort to get the U1250 truck all fixed up, I would have to get something like a U1700 just to carry the extra weight. So I decided to hire a mobile weigh bridge.


The results were:

Truck - 4700kg

Parts to go:

Front Winch - 50kg
Sprung Mattress - 50kg
Windows and glass - 50kg
Floor - 75kg
Spare wheel - 100kg
Furniture & Lining - 100kg
Fridges - 50kg
Solar Panels - 40kg
Toilet - 35kg
Stove, Calorifier, water pump etc, 50kg
Roof Rack & Bull Bar - 100kg
Insulation - 100kg
Batteries & Chargers - 250kg

Other stuff:

Fuel - 400lt
Water - 300lt
Food etc - 500kg
People - 4 x 75 = 300kg

Total 7250kg.

That gives me only 250kg up my sleeve, which is not that much but should just be enough. The good new is that the diet has worked, and Mog is on track to come in under the 7.5 ton maximum limit.


I have to finished all the things that need the cab tilted to fit. First the heat shields on the cab itself - the new turbo has moved the exhaust brake a lot closer than the original turbo, but with the heat shield, the ceramic coating and some more insulation, I think that should be enough to keep the heat out.


The next thing to fit was the throttle linkages and the accelerator pedal. I still have to fabricate a few bracket to hold the plastic cover plate in place, but the accelerator and the hand throttle are all fitted.


The main work on the weekend before the flood was on the floor. This is the first stage of my new floor. First I have to cut out the templates for the various floor panels. This took quite a while to get right. I have to make sure I can fit the floor in around all the various bracing and brackets. The joins have to line up with the structure of the subframe. I have to weld in one more support on the joint directly in front of the bed, and then the floor is basically finished.


The next stage is to cut the aluminium to size using the templates as a guide. Then I will send the aluminium over to get the foam and plywood stuck to it and vacuum bagged together. Whilst that is happening, I need to paint the inside of the truck. Everything will be primed using an etch primer, then painted with two pack epoxy paint. Before I can start the painting, I have to finish the window frames. This will be made from aluminium box section, and then glued into position using the Sikaflex. I will also drill all the holes for the wire conduits as well, then spray the inside of the box sections with some cavity wax to keep the rust at bay from the inside as well.


The next thing to figure out is how the shower area is going to work. I have to make sure the floor will slope to ensure the water ends up in the tank. I also need a place for the stairs to fold up underneath. I've seen a lot of designs, and I think I know how it's going to work.


The floods in Brisbane meant that our office was closed. My wife and I went up to help, but got turned away by the centre saying they had too many people already, so I decided to make the most of the time off by progressing the Mog.

First thing was to cut the aluminium for the floor. I made some straight edges from the spare plywood, then trimmed the plywood templates using a top bearing router bit to the exact size allowing for a 3mm gap for the Sikaflex between the panels. I then did the rough cut on the aluminium using the plasma cutter, then using my router and a edging bit, I trimmed the aluminium to an exact match to the plywood. The result was a nice smooth edge on the aluminium and straight cuts (for a change). The photos show the rear section under the bed and the front section under the seats.

I took the aluminium and plywood templates up to a friend who will turn the aluminium into a composite panel. All going well I will get them back next week and I can fit the floor.

I also built the aluminium window frames - made from 38x25mm aluminium they reinforce the aluminium around each of the windows - just in case.

Next was the storage hatches. First the left hand side, which will also include a fold out table. Then the rear hatch, which is the "boot" of the truck, and will hold a fold out kitchen and it will also have a few shelves, but we will sort all the storage out once we get through the first couple of trip, them we will know what we need and what we don't.

Next was to sheet the rear and the storage hatches with the aluminium. If you think you can use a manual glue gun when applying the Sikaflex, then you have forearms like Popeye. The forklift makes a great table for these sorts of things. Gluing aluminium with Sikaflex is a four stage process. First you have to sand the surface with a course grit sandpaper, then using the Sikaflex cleaner. That has be allowed to dry for a minimum of 10 minutes before applying the Sikaflex primer. Then you have to let that dry for 20 minutes, only then do you get to put the Sikaflex 252 glue on.

The photos show the framing and the finished product looks like - all the panels are on, and the infill panels either side of the rear hatch and above the hatch have been glued on.

I decided to to order in a oil and water line kit from Japan for the GT2860 turbo - I ordered it on Friday last week, and it arrived on Tuesday. I needed a few adaptors to fit the oil drain onto the oil pan, and the oil supply line from the block which I ordered from my local hose shop. . I've got some high temperature silicone hose for the water lines from Autobarn - my local car parts place after the specialist hydraulic hose and fitting place did not know where to get it. I will use that to connect the turbo cooling lines into the heater circuit. It must be Japanese efficiency that enables them to supply a high quality hose kit all the way from Japan for 1/3 of the price and in about the same amount of time it took for my local hose place to order in a few adaptors.


I also decided to get the door fabricated by my local sheet metal shop - the guys that have been doing all the cutting and folding of the aluminium for me. I didn't trust my ability to make the door flat enough, and the curved edges were fairly tricky to make. They did a great job, and it fits perfectly - which means I actually managed to measure something correctly for a change.The photo show the guys from Ryan's Sheet metal in Springwood that have helped me out so much. I hung the door using some heavy stainless steel hinges. I will have to slot the holes in the door, to make the final adjustment to align it so that the seals are all tight, but it works fairly well. When I get it all aligned properly, then I will add a third hinge in the middle.


The final bit of sheet metal work this week was the cladding of the side pods and the mudguards. The biggest Hella led lights fit perfectly in the corner - and the look great as well. I'm back to work tomorrow in a temporary building, so I will continue in the evenings and weekends again. The plan is this weekend to the access hatches frame work to the rear pods, and get all the rest of the cladding done on it at well. All going well, next weekend I will be fitting the floor, then it will be on to the interior fit out.

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