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19trax95's 1986 CUCV M1028A1

15451 Views 342 Replies 24 Participants Last post by  19trax95
So I have been looking for a decent square body for some time now. Didn't really have my eyes on anything in particular, but the frame and body needed to be in as good of shape as I could find.

Last week I came across this beast on marketplace up in Massachusetts. It's a 1986 Chevy M1031. Which is the military CUCV service truck.

It is I'm great shape. Frame is rock solid, and the cab has very, very little rust. It is also mechanically sound. A couple little leaks, but that's to be expected.

It has the 6.2 diesel, th400 trans, np205 t case, king pin Dana 60 front axle with a limited slip, 14 BFF rear with locker, and 4.56 gears. The service body is all aluminum. It used to have a PTO driven generator and air compressor, but those have since been removed. The PTO is still on the t case though.

My plans are to keep it fairly original, but add a few creature comforts to suit me better.
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So they are calling for 25-30mph winds tomorrow, so drone is likely out.

However, I have revised my plan slightly. I'm going to use the forklift to remove the service body, since I feel that will be easier and safer given the winds. And then use the wrecker to remove the bed from the trailer and I'm going to attempt my skills to flip the bed with the wrecker and set it right on the truck.

In my head it's going to work great. In practice, we shall see lol. If it doesn't work good, I'll have a handful of other guys in the shop so we'll just do it the old fashioned way. I'll take as many pics as I can during the process. If it wasn't winter I would be cleaning the frame and painting it, but it's a bit cold for paint and I'm short on time. So that'll have to wait until spring unfortunately.
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Pics to follow when I get home. But status update, service body is off, bed is off the trailer, working on flipping it now, and then setting it on the truck.
Here's some pics as promised. I ended up not using thr wrecker. I found a easier and quicker way to flip it.

I stacked pallets in front of the bed, set it on the pallets and stood it up the tall ways. Then tipped it back down onto the forks and went right on the truck with it. Worked like a charm.

The service body came off with zero issues as well.
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Are you going to paint the bed green, or paint the cab/front-end camo?
I've debated going back to the camo on the full truck. But I think as of now, I'm going to paint the bed green to match the cab.
Pretty easy to go camo later if you wanted to.
Yeah there is the military documents for the correct pattern and what colors go where. Either way green is the base, so that would need to go on the bed regardless.
Got the lights all wired up and the connectors installed.

The diagrams were off a little since the M1031 version of the CUCV tech manuals are classified. The rest, M1008, M1009, M1028, and M1010 are available. Reason being (from what I have found) is that the M1031 was also used an an EOD vehicle, so everything regarding it as far as manuals go, is classified still. Doesn't make a ton of sense to me, but that's what I have found reported by numerous sources.

So anyway, the difference was in the harness that goes from tail light to tail light. The reverse wire comes out of the main harness as one wire, then there is a splice and goes to both sides. Same with the brake/turn wire. Was extremely simple to overcome since I just mimicked how it was connected originally. Just found it odd how it was done on the M1031 vs all the others.

But here's some pics. I still need to polish and clear the lenses, but they work now to I can drive it without the trailer hooked up lol. I also really need to get some weight in the back of this truck. I deleted the rear load sensing brake valve, so without the weight of the body on there, the rear tires lock up much easier than I'd like.
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So I ran into a slight issue tonight that I didn't quite think of at the time of installation of the bed.

It seems as though the filler neck from the service body is bent in an opposite angle when compared to the pickup versions. At quick glance I had assumed I could just loosen the clamp and rotate the neck around the bolts line up. But that is not the case. I didn't take note of the angle that the hard pipe section is formed at, meaning when I tried to rotate it, the bend hits the bed and doesn't allow it to fit.

Getting fuel was a slow process due to this lol.

I and going to work more on it this weekend when it's light out. I think I can make it work still, but it'll take a little creativity. I do not want to cut anything since these military style fill necks (different from the civi trucks) are rare and expensive. So if I can help it, I'd much rather not do any modification to the neck itself. The hose I can get for $20, so I'm not too worried about having to trim that a little.
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Does it hit immediately when trying to start rotating it or just cant get it to rotate the full 180deg?

Also I never noticed that giant pintle hook, what is it attached too?
I can rotate it all the way around, but the issue is when I go to install it in the bed, it is angled wrong so the neck hits the bed before the bolt holes line up.

I was thinking some more last night and I have some ideas. One of which requires modification to the filler neck, but if I need to do it to make it right I will.
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Oh and the pintle hitch is attached the the bumper. These have extra support bars behind them and are far heavier than the standard bumpers. The parts that the hitches are attached to are a little over 1/4" thick steel plates.
So today we had our big temp drop. Had out Christmas party at work and when I got there st 7am it was 50 degrees. When I left at 2, it was 21⁰ and now its 13⁰. I never got a chance to install the blow heater in the truck so for shits and giggles I may try and fire it up tomorrow morning and record it for you guys to see how hard it starts. I need to run my Christmas gifts over for the Ole lady and kids tomorrow morning so either way one of the trucks will need to start. The duramax will be the backup plan since that has a block heater that I just plugged in.

The low is 8⁰ so so by far the coldest either one has had to start up in as long as I've owned them.
Well I'm feeling mighty dumb lol. I setup my phone to record a cold start video. I planned to use the s pen to start recording. But I forgot to switch it to video instead of photo. So all I got was one picture of the side of the truck lol.

But at the current 7⁰, the truck wasn't too happy to wake up. Took 3 glow plugs cycles and two cranking sessions before it fired up. Honestly not too bad given it's an IDI motor with I don't believe all glow plugs working. After I deliver gifts, I need to tow my buddies cummins since he gelled up hard core and can't get it going.
Well my passenger side alternator (gen 2) decided to give up the ghost. I have a spare that came with the truck, but that is just the old one from when the previous owner replaced it. So now I have two dead ones. I need to order a new one.

They are special since they are an isolated ground (for the 24v system). They are expensive but not horribly so. I can get one for right at $160 from the same place that the previous owner got the driver's side unit.

They aren't open until Tuesday so I'll likely order it Monday night.

In theory I could get a non isolated ground unit and swap the drivers side to the passenger side, and use the standard alternator on the driver's side. But I'd rather just spend the extra few bucks and keep it correct across the board.
So I took some time today while I was seasoning my Blackstone to get the tailgate hardware swapped in. Went pretty easy. New hardware lined up perfectly and works great. Until I went to put it on the truck...

Turns out the passenger side of the bed is pushed in a little. Only about 3/8"-1/2" or so. So the tailgate wouldn't close since the latch hits the bed before it will close. I have temporarily remedied this by using my cargo bar to spread the edge of the bed outwards a little. Once I did that, the tailgate fits and opens/closes nicely.

So tomorrow or at some point this week, I will attempt to pull out on the right side of the bed and for lack of a better term, bend it back, to where it should be. Might use the old come along to a tree method first. If that doesn't work, I'll go to work and use the Porta power and spread it that way.

Also added a front plate because I was gifted it for Christmas and I don't have a front plate mount for the 15, but this one does.
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At first you don't succeed try again
Pretty much lol. New alternator was also ordered last night. I think I'll pickup two rebuild kits and rebuild the now two dead ones I'll have so I have spares on hand. I can get two rebuild kits for around $95. So that sure beats $160 for a new one.
Tomorrow is going to be a (hopefully) productive day for the truck.

In going to do glow plugs and the connectors for them, install a tach, and do some wiring for my radio and light bar. I got a little fuse box that I'm going to wire up with a relay that is ignition triggered so the box is only hot with ignition on. That way I'll have the radio and all wired up to it instead of the fuse taps I'm using now.

Will be a cleaner setup for sure. I also got a shorter belt for the driver's side alternator since the one it calls for is a little long and almost maxes out the adjustment. Not sure if the one I got will be long enough though. It's around 1.25" shorter. So I'll see. New alternator should be here Thursday, it shipped already.
In case anyone reading the thread should find them helpful, here are the diagrams for the CUCV trucks. A lot of these crossover to the squarebody trucks as well, but some of it is unique to the CUCV series. I also have the full service manual for the 1986 model year square body trucks in this folder. It covers all engines, full electrical, diagnostic procedures, drive train, etc.

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