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19trax95's 1986 CUCV M1028A1

16060 Views 358 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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I like those wheels and tires. I am assuming you need a bit of lift to run them? The look pretty big.
Yeah most guys say it needs a 4-6 inch lift to clear them.

I'm going with a 4" lift, and then the zero rates are 1" thick, so technically, the total lift will be 5". They are 37" tall by the sidewall size, but measured out, not on the truck, they are 35.5" tall with the 75% tread they will have.

If I didn't mind trimming the fenders, I could get away with a 3" lift but I want to try and trim as little as possible. If I need to cut some, it's fine since the very bottom lips of both fenders have some rust anyway, so if anything, all I'd be doing is cutting the rusted edge off lol.
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Put some better clamps on the exhaust today. The passenger side had a small leak at the clamp since I reused the old ones.

I also finally installed my washer pump. Even though the truck is a 1986, GM used the 1984 spec when building the CUCV trucks. Which means the washer pump is built in to the wiper motor. They are failure prone and just aren't the best. So last year I bought a pump for 86, but it is basically just a generic acdelco washer fluid pump. I drilled a small hole in the bottom of the fluid tank, pressed the rubber seal in, and pushed the pump in there.

I then extended the harness from the original power and ground for the washer pump solenoid, and connected it to the new pump. I had to install a new section of hose since the original was too large for the pump. I had a spare section of fuel line around so I used that.

For now I'm just using the old pump to split it to the two nozzles. It doesn't leak so I'll likely leave it like that unless it presents an issue down the road.
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Got my new bulbs for the cluster this past weekend. Went with some super bright led bulbs. Opted for the COB glass bulb style. Got 4 of the natural white ones for the back lighting, 2 green for the turn signal indicators and a blue one for the high beam indicator.

The rest can stay incandescent for the seat belt, brake, oil pressure, and glow plug. Two two for the alternator lights need to remain incandescent since they are part of the circuit. And one needs to be a 194 and the other a 168. They can not be swapped as it will mess up the exciter circuit to the alternators.

Will post pics once I get time to install them.
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Headed to the junk yard tomorrow after work. Going to see what they got. Mainly after a 88-94 gmt400 steering wheel, a 83-87 tilt column, and maybe a decent bench seat.

As well as anything else I find that's cool lol. Maybe a sliding rear glass. I haven't been there in many years, so I'm not sure what vintage of vehicles they have anymore. But I'll find out lol.
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From my experiences around here, squarebodies and obs trucks in junkyards are getting few and far between.
Yeah last time was at my local yard, gmt400s were fairly prevalent, but usually tore up pretty good. Squarebodies were few and far between, and the ones that were there, may as well have either gone through the crusher, or sat in a salt pit for the last 15 years lol.

But for the bench seat, I have tons of options. I can grab one out of anything full size and GM for the most part. I'd prefer a split bench with console out of a gmt400, but I'll see what I find if anything
Welp, I consider today to be a win.

Spent about 4 hours at the junk yard with my buddy. I left with a bench seat, steering wheel, and rear view mirror.

The GMT400s were plentiful in various states. Most were pretty beat and picked clean. But I found two options for seats. Actually right across from one another. The first was a 1988 c2500 with a bench with armrest. Next option was a 97 crew cab dually with a vinyl bench front and rear seats. I opted for the first truck. There were a bunch of others but none quite as clean as this one. It is red, which isn't my first choice, but I can make it work.

The steering wheels were a dime a dozen. First I found a base model gmc. I pulled that wheel. Then right on the next row I found a silverado with the leather wheel and Chevy horn pad. So I swapped those out.

I then grabbed a mirror out of a random gmt400 I found on the way out.

My buddy got a mint bench seat for his 79 Ford as well as some hvac controls for his car. View attachment 953707
Wheel Motor vehicle Automotive tire Mode of transport Alloy wheel

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Not sure why the pic of the seat won't upload. So let's try it in a separate post. Also, total spent for the seat, wheel, mirror, and admission to the yard was $30.
Vehicle Car Motor vehicle Hood Plant
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I've never seen a bench seat with a fold up armrest. That's cool!

And that red...pimptastic! haha
Yeah I was really after either tan, brown, Grey, etc. But the red will work. The door panels are sorta kinda red lol.

And for what I paid for it, I bet I could sell it and double my money. The arm rest is neat. Its missing a bolt so it folds out kinda weird at the moment. But it's nothing special so I'll throw a new bolt in there, swap the bases over, and install it.

Unfortunately tomorrow looms like rain/snow so it'll have to wait
Couldn’t be too much to get it recovered could it?
I looked into it for the original seat. It's pretty pricey around here. Around $500.
I got the new wheel on there. Was going to do the rearview mirror as well, but it's a bit cold fir that. I prefer doing that when it's warm since the glue seems to stick much better.
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Nice scores!
I took my turbo to work and got some new mounting studs and nuts for it. I also removed the two old studs that were in there yet.

Turns out the turbo studs off a maxxforce DT fit lol. It's an m10x1.5 in the turbo flange. Then the new studs are m10x1.0 on the nut side. The old ones were M10x1.5 on both ends.

Only potential issue is the nuts are a flanged 15mm head. So they may hit the manifold. I'll need to test fit it.

If they hit, I have some out of a Cat 3126 that are a 14mm, non flange pinch nut. I know they will clear.

Also the turbo shaft has been soaking in CLP for the last few months. Safe to say the carbon is gone now. Just had to wipe off the remaining little bit. Now I can finally clean up the shaft and center section of the turbo and assemble the new bushings and all. I may paint the compressor housing. If I thought I'd last I'd paint the turbine housing. But there's just too much heat there. And I'm not spending the money to get them ceramic coated.
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What is CLP? How how does the turbine housing get? I painted an exhaust manifold on a project car with some high temp paint and it seemed to hold up. I was actually expecting it to just burn off. It was not this exact product I dont think, but something similar.
Well exhaust temps at the manifolds can reach around 1200⁰+ ideally lower though, especially on these motors lol. My duramax I've hit 1250⁰ on the dyno.

So in theory, a high temp paint like that should hold up. But it has a stainless heat shield that goes over it anyway. So I may just paint that black with some exhaust paint.

CLP is a gun cleaner. It's a oil like fluid that helps soften and remove carbon build up from firearms. But as it turns out it also works for exhaust carbon. Which makes sense because the two are very similar.

I got the turbo all rebuilt and dry fit. I just need to pop the front plate off the compressor side and seal it up, seal and install the compressor cover (after I paint it), and then install the whole thing onto the exhaust housing.

The waste gate will be modified a bit as far as mounting goes. I want to change it so I can manually adjust the PSI at which it opens.

The rebuild kit I got was a bit confusing for two reasons, one of which is the fact I took it apart over the summer and didn't remember exactly how it went back together, and two, it's for all the turbos, GM3 (this one), GM4, GM5, GM6, and GM8. So the seal rings didn't match up exactly. I did reuse one of the old ones. It should be OK, but if not, at least it's on the easier side to remove so I can be done on the truck if need be.
Wood Auto part Font Flooring Engineering
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Got the plow on last night. Now its guaranteed we'll get no snow today lol. Wasn't too fun getting it on there. The foot fell off the pallet I had it on so it was about 4" too low.

I'm also exceedingly close to ordering my lift and picking up my tires. I was actually going to order the lift the other day but the shocks went on backorder. So as soon as those are in stock again, I'm hitting order.

The tires are fairly local so I'll just go and get them to avoid the huge shipping cost. I'm also hoping if I throw the guys an extra $50 they will hand pick the best of the bunch for me lol.
Automotive parking light Car Automotive lighting Hood Vehicle
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That would be nice of them. I tried zooming in but couldn't tell what the date code on the tires were. But they are obviously used, but I don't see any dry rot either like was on my just 4 year old tires. Were these used in service for a short time and replaced well before needing it? These types of tires specifically have a much longer service life I assume, so you wont be worried about getting good life out of them?
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