Another M105 trailer modification- add Unimog Radio Box

tennmogger

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This project is to put a Unimog 404 radio box on an M105 trailer frame/axle. Maybe the modifications on the M105 will be helpful to others, especially the method used to extend parking brake and service brake linkages.

M105 trailers are nice trailers. M105 beds seem to be favorites for use on 'bobbers' and that has left some orphan rolling chassis available

I camp a lot in a Unimog U1300 with Alaskan camper. There's not much room in these campers so I give my wife preference over radios. With a radio communications trailer behind the Unimog I get to chase that hobby too!

Here are some pictures of the process. The trailer is picked up at SSGR14, thanks to RECKLESS.

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Flipped it over and removed axle supports, drilled new holes, and reinstalled the axle almost all the way to the rear. The exact position places the wheel-wells of the radio box over the trailer wheels. A lot of the weight is transferred to the tongue but that is no problem for the U-1300.

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Painted the bottom then flipped it over again and painted the top. Then the brakes were modified. A piece of heavy Unistrut was cut to bridge across the frame. The Unistrut was mounted on the same bolts as the front spring hangers.

The parking brake cable ends were secured to the Unistrut with Unistrut nuts, two square washers and bolts. This was a direct bolt-up with no piddly work.

Extending the linkage was done with off-the-shelf threaded rod and coupling nuts. The turnbuckle is 3/8-24 threads so rod was bought to match. Got the rod and nuts at Fastenal. Just cut the length you need and screw it all back together. Antiseize paste was applied where I didn't want paint to lock up threads.

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That's the progress so far.

I will add pictures of the box to be installed on the trailer. Then the box will be refitted with the original furniture and goodies.
 
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gimpyrobb

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**** nice project! I'm guessing that crane has to be used stationary, or can you travel with it?
 

tennmogger

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**** nice project! I'm guessing that crane has to be used stationary, or can you travel with it?
The crane is fully mobile. I don't find a picture showing it (to follow) but the boom rotates around and lowers on the guide on the ROPS, the stabilizers tuck up, and it's narrow enough to drive on highway. With the weight up high I usually limit my speed to 35 mph or so.

Bob
 

Recovry4x4

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That is going to be a super nice setup Bob. The mog radio box is perfect. Can't wait to see it. Are we going to see it at the rally in October?
 

tennmogger

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The 1985 Zepellin-built radio box (from a 404 Unimog) went onto the modified M-105 trailer frame yesterday:

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The old but rejuvenated Pitman Polecat hydraulic crane (mounted on a 406 Unimog) handled the box well.

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The black "yard truck" is a 404 Unimog being brought back to life after sitting unused since last century.
 

tennmogger

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That is going to be a super nice setup Bob. The mog radio box is perfect. Can't wait to see it. Are we going to see it at the rally in October?
I'd say the chances are very good :) I still have to renovate and install the furniture into the box, including the front radio table, and left rear side table.

Still on the lookout for a suitable mast for this box, either a telescoping triangular tower (40 ft range) or pneumatic type as used on news-gathering vehicles. Maybe I'll get lucky one day and find the original mast that fits the clamps on the rear door! In the meantime, push poles will work.

Bob WB4ETT
 

Recovry4x4

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Hey Bob, tell me about your spreader bar. It looks like 2 of the drawbars Derek Taylor was selling. Hmm, new idea.
 

tennmogger

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That is the original Unimog "buddy bar" for towing. It links the Ringfeder pintle hitch of the towing vehicle to the standard tow-bar receptacle on the towed vehicle. The use as a spreader is a bonus! It's as if it were made for the job. One day I'll swedge/swage up some cables to replace the chains.
 

tennmogger

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Update on progress.

The front desk is tidied up and installed. Front heater ducting removed (will use portable heater, propane or electric depending on facilities available).

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A PRC-174 transceiver is installed temporarily to test an articulating mount. Works great! These radio boxes are loaded with mounting channels that use 'T' bolts. Very handy! The 'T' bolts can be made from carriage bolts by lopping off two sides.

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This is an Israeli PRC-174 with automatic internal antenna tuner, USB, LSB, AM, narrow and wide CW modes, covering 2 to 30 MHz. This mounting position is easily used from the ground outside the box. It tucks up against the wall when the mount is rotated.

left rear AB-15 and antenna.jpgright rear AB-15 with cover.jpgLeft rear AB-15 grounding solution.jpg

Two of the five antenna portals are populated now (not counting the two rear door masts). The rubber covers are the German waterproofing solution for the AB-15 type mounts. One photo shows a grounding method when the original AB-15 ground strap is missing (heavy copper braid and an alligator clip). I am still looking for 'thumb screw' tubing clamps as originally installed.

Next time there should be more radios installed.

Bob WB4ETT
 

MilChevyguy

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That mod of the trailer frame is a great idea, and adding the box is great......and keeps the wife up front where you can talk!!

Seeing this thread gave me an idea, anyone mount an M1010 box a trailer frame?? Nothing came up in search, but I could be missing some key words.
 

tennmogger

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MilChevyGuy,

Have not seen an M-1010 boxed trailer but that could be a good combination. However, if mounted on an M-105, the M-1010 box would really be up in the air. The '1010 is much taller than the 404 box. Of course that's a good thing for creature comfort but the center of gravity would be getting high.

Do you still have the M-1010 truck and box in your avatar? That looks like a great rig. Why change it?

Bob
 
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tennmogger

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The first outing!

Our local Mil Veh group, Knoxville Military Vehicle Club, set up a stationary display in front of the American Legion in Rockwood, TN, last week. This was the first long tow and event for the comm trailer (now designated M105A404 !).

The trailer towed great and the U-1300 hardly knew it was back there. The longer wheelbase makes it a pleasure to back up, too. I did discover that I can't see the trailer behind me when driving straight ahead but it comes into view with the least turn.

The Vets enjoyed the display and the Town festival.
 

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oilcan

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Thanks for the link to this thread, Bob. I've been offline for a while and missed it.

Bump for updates!
 
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