CUCV more questions than answers...

[Zen Diesel]

Gentlemen,
I call upon your collective knowledge once again. The usual disclaimer to please excuse my ignorance. I really love my truck (that I still haven't started because I need to work through obvious mechanical issues first). I digress.

I need some help understanding more things about my truck and I did a bunch of google-fu and I am still very lost.


My truck is a 1984 M1008 and it has holes punched in the truck bed for the possibility of mounting 4 antennas on it (or 1 antenna in 4 possible places). Yet I can't find any pictures of documentation of this truck carrying radios of any kind on it. I understand the M1028 did have that capability but from the pictures I have seen the radio antenna is high mounted on an ambulance box and not the body of the truck and looking at the vietnam era through desert storm variants of radios that would use the MX-6707 antenna mast and antenna. Those radios are massive. Massive in the kind of way that your passenger either doesn't have legs or wouldn't mind sitting sideways on the bench in the tiny cab of my truck. I am at a loss. As configured my truck is not a radio truck or an ambulance but it has holes punched in it for options that would be non logical considering how large military radios are. So I am trying to understand why my truck has mounts for 4 masts and additionally why something that was never a radio /comms truck was thus equipped.


Along the same lines I found a port for what I assume was once a 20ish so pin connector in my truck bed. That was apparently "bedlindered" and then put back in place....? This again is a huge question mark. I have limited information about the origin of this truck since it was "demilled" by painting over its previous assignment.

I have not found much information about how these trucks were used outside of some very generic information and 99% of that doesn't have photos. At 29K on a truck of this vintage its basically a lot queen. My wife puts more miles on her car in a year.


I purchased both a military antenna base / tuner and mast (I already have my ham tickets) and the appropriate and a set of *holy cow* expensive pieces of sheet metal to mount said gear to my truck. The *cool location behind the cab * to mount my antennas seems like it is a stupid location to mount them for HF. If I had to guess before mounting them and plugging in my analyzer I would guess the better location would be the holes closest to the tailgate. Which again leads me to a question of even in a NVIS situation why even offer a option for a potentially poor mounting location?


Okay so my next question is less asthetic and more technical. But why in the world would a person do this to a gas tank?


Finally I am trying to understand the markings on my truck. I have cancer in the usual spots and this is going to necessitate a repaint after I correct the rust areas. I am going to try to return the truck to as original paint scheme as I purchased it in. However I would love to understand what some of these markings mean.



Any help is appreciated!

-ZD-

 

[dougco1]

Okay so my next question is less asthetic and more technical. But why in the world would a person do this to a gas tank?
View attachment 777134View attachment 777135
That looks like wood shims and spray foam to keep the steel tank protector from making an annoying rattle at idle. You may want to remove it so it doesn't promote rust.

 

[Zen Diesel]

Okay so my next question is less asthetic and more technical. But why in the world would a person do this to a gas tank?
View attachment 777134View attachment 777135
That looks like wood shims and spray foam to keep the steel tank protector from making an annoying rattle at idle. You may want to remove it so it doesn't promote rust.

*Sigh*
Yeah I am in the process of replacing all of the rubber lines on the truck so I planned to drop the tank. I thought that may have been the case. The funny thing is the anti rattle stuff goes on top of the tank not the bottom.... I guess I am heading to walmart for some cheap gas cans. Thank you sir. I appreciate the feedback.

 

[cucvrus]

The truck you have is an M1008A1. It had a radio rack in the back and a 24volt power cable that connected to the 24 volt buss bar under the hood right side of firewall. It extended under the cab and into the truck bed on the right front corner. The capped connection on the bed wall never had any guts in it. it was for screwing the power cable into when not in use. That is how I bought a few. The shelves made nice book shelves for my office. They were made out of aluminum and very stout. I never had much use for the cables and still have a few stashed in an M1010 body. I agree that the spray foam was to prevent the rattles and also that you should eliminate it. The rattle comes from bent supports and loose mounting. I would recommend removing the bed and doing a complete and through job on the cab corners and rocker panels.
Also it will also allow complete access to the frame and fuel tank and you will be able to do a fantastic job at getting that area all clean and painted. I would also turn the bed over or on end and wash, clean and undercoat the bed floor bottom. A little PM and extra work goes a long way to preserve and slow the decaying process. But do it right the first time. Good Luck and have a Great Day. Be Safe.

 

[Zen Diesel]

The truck you have is an M1008A1. It had a radio rack in the back and a 24volt power cable that connected to the 24 volt buss bar under the hood right side of firewall. It extended under the cab and into the truck bed on the right front corner. The capped connection on the bed wall never had any guts in it. it was for screwing the power cable into when not in use. That is how I bought a few. The shelves made nice book shelves for my office. They were made out of aluminum and very stout. I never had much use for the cables and still have a few stashed in an M1010 body. I agree that the spray foam was to prevent the rattles and also that you should eliminate it. The rattle comes from bent supports and loose mounting. I would recommend removing the bed and doing a complete and through job on the cab corners and rocker panels.
Also it will also allow complete access to the frame and fuel tank and you will be able to do a fantastic job at getting that area all clean and painted. I would also turn the bed over or on end and wash, clean and undercoat the bed floor bottom. A little PM and extra work goes a long way to preserve and slow the decaying process. But do it right the first time. Good Luck and have a Great Day. Be Safe.

Cool thanks for the info! Now that I know the designation I can read up more on this variant!

The bed is eventually going to come off. I have a few cancer spots on the bottom that need to be addressed. I ordered a Contour SCT from Eastwood to help make quicker work of the scaly stuff on the frame rails and leaf springs etc... Going to wind up doing a rust converter and then rust encapsulator and then topped off with cosmoline for the lighter stuff and for the cancer its going to get cut out and replaced with new sheet metal. The bottom of the doors on the driver side and the corner on the passenger side are toast. So I have patch panels coming for those, the rockers and cab corners survived the poke test but I will dig into those later. Fortunately I live in the high desert so I have a little more time to work on the rusty stuff later.

The truck bed is coated in roll on truck liner and it is heaviest around the mounting hardware (of course). I'm going to get it running first so I can run up to Harbor Freight and get an engine hoist so I can fab up a bed lift. I want to get under the bed and chemically convert then cosmoline all of that stuff under there. Truck bed has some concerning cancer spots on the bed rails and its not going to be possible to do the repair correctly with the bed in place.

I'm waiting for Summit to open so I can go pick up my cheapo electric diesel lift pump. I need to get this truck pulled into the garage. So I am going to cobble together a diesel IV just to get it moved in. I've been chasing air leaks out of the fuel system. Oh my it leaks everywhere. And I figured out the anti-siphon valve on the mechanical pump is toast. So I am picking one of those up from Summit too. With all the stuff I have to pull to get to that mechanical pump I may as well go ahead and do the harmonic balancer while I am at it. Turns out "just changing the fuel lines" turned into addressing all of the major mechanical issues and PM stuff.

So I have a question about electric fuel pumps. Can I plumb in an electric fuel pump as an aux pump and just draw the fuel through it when its not needed? Will that create any problems with the pump? I am keeping the mechanical pump but since I am doing this work to the fuel system I may as well put in a back up pump just in case I need to prime the fuel system away from home. Also any recommendations for an electric fuel pump? I'm picking up a cheapo pump just to get the truck started and to drain my fuel tank so I can drop it and inspect it. But I am willing to spend a little more coin on a better electric pump for aux purposes.

The only thing I love more than working on old trucks is driving old trucks.
Thanks for the info!

 

[cucvrus]

My advise. Get it running first before going out and spending money on non stock add on stuff. I suspect it could have a bad injection pump if it has been setting a long time. That is $350 + or -. Get the fuel lines replaced, fuel system tight and go from there. The mechanical lift pump is about $40. and be sure to get the $1.00 push rod cover gasket at the same time as the fuel pump. After it starts, drives and runs good you can make updates as needed. I have had great success with good running stock CUCV's. I have never replaced a harmonic balancer just for the sake of replacing one. I have spent the coin on getting the starter rebuilt , AC Delco 13G glow plugs and new batteries after I am sure the engine is worthy of spending more on it. I actually changed head gaskets more than harmonic balancers. But to each him own. The CUCV can quickly snowball into a money pit and there will be no end to spending and time spent doing updates and repairs. Start small, think big, and repair as needed. Up and driving will be the tell all. A 35 year old vehicle has it's own mind set. Don't make it your daily/primary mode of transportation. It will let you down when least expected.I've been there done that when they were 10 years old. Good Luck. This is honest positive advise. I have experienced first hand. Have a Great Day. Be Safe.

 

[Zen Diesel]

For anyone interested I found a picture of the radio rack and some of the original power equipment as it was on the trucks.

photo credit: http://webhosting.web.com/imagelib/...ilderpictures/IMGP4391.JPG&target=tlx_picqrtw

 

[Zen Diesel]

My advise. Get it running first before going out and spending money on non stock add on stuff. I suspect it could have a bad injection pump if it has been setting a long time. That is $350 + or -. Get the fuel lines replaced, fuel system tight and go from there. The mechanical lift pump is about $40. and be sure to get the $1.00 push rod cover gasket at the same time as the fuel pump. After it starts, drives and runs good you can make updates as needed. I have had great success with good running stock CUCV's. I have never replaced a harmonic balancer just for the sake of replacing one. I have spent the coin on getting the starter rebuilt , AC Delco 13G glow plugs and new batteries after I am sure the engine is worthy of spending more on it. I actually changed head gaskets more than harmonic balancers. But to each him own. The CUCV can quickly snowball into a money pit and there will be no end to spending and time spent doing updates and repairs. Start small, think big, and repair as needed. Up and driving will be the tell all. A 35 year old vehicle has it's own mind set. Don't make it your daily/primary mode of transportation. It will let you down when least expected.I've been there done that when they were 10 years old. Good Luck. This is honest positive advise. I have experienced first hand. Have a Great Day. Be Safe.

Good advice I will take that to heart. I will hold off on the harmonic balancer. I had read it was an issue with these engines but if I can go without changing it I will stick with that. Its easy to get to all things considered. It has been sitting for 2 years so I am hoping the IP is still good. IDK I will find out in a couple hours. My truck isn't stock. The Turbo 400 was replaced with an 4L80E, my IP is turned up and it has the Banks sidewinder on it. Its not a coal roller by any means just more fuel to get the turbo spooled up when hauling. I'm not trying to hot rod this, this is donkey not a racehorse. I live up in the mountains, if I was NA this truck may as well have an AG triangle on the back, we have long hills out here. The starter looks new(er) that which isn't covered in oil. I hope its a good starter and not some questionable Asian market rebuild. The ballast resistors are gone, the "Doghead starter relay mod" is in place and glowplugs have been converted to manual. Previous owner deleted the CDR when the turbo was installed so now its coating the bottom of my truck with anti rust agent. That is next after I get it running. Finally scraped together enough parts to get that CDR back in place.

I'm not looking for extra work I have enough to address and unhack as it is. Its not a daily driver nor will it be. Around town truck and a weekend escape vehicle. As far as a money pit is concerned its cheaper than having kids or an illegal drug habit and its something to do on my days off. I used to own a Unimog. I loved that truck but vintage diesel Mercedes military trucks.... you have to love troubleshooting and working on them and hunting down parts. Fun trucks off road but you really need to haul them wherever you are taking them because they are no fun at highway speeds.

 

[Tinstar]

I would replace the harmonic balancer.
Especially if it’s original.
The rubber on mine was hard and cracked and starting to separate from the Steel.
Not far away from complete failure.

It’s no secret that more than a few 6.2L diesels have broken crankshafts directly related to old and worn Harmonic Balancers.

Acdelco still makes one and it fits and functions perfectly.
Replace your front crankshaft seal while you’re at it.

 

[Terracoma]

Finally I am trying to understand the markings on my truck. I have cancer in the usual spots and this is going to necessitate a repaint after I correct the rust areas. I am going to try to return the truck to as original paint scheme as I purchased it in. However I would love to understand what some of these markings mean.

View attachment 777142View attachment 777143View attachment 777144

NG1EZ3 or NG1EZJ should be your registration number, and it should match the reg number on the data tag in the driver's door jamb... I say "should", because sometimes data tags disappear, or perhaps your truck got another truck's brush guard at some point along the journey.



Modern army unit marking should describe: Command<>Brigade<>Battalion<>Regiment<>Company<>OrderOfMarch

The first photo of the passenger's side bumper seems to show 57BDE-1-1, but there also appears to be the faint bottom half of a "2" after the second "-1"...which would jive with the 1/121 above the driver's door handle in the third photo. So that gives us the Brigade (abbreviated as BDE) thru Regiment of 57BDE-1-121, which translates to 57th Bde, 1st Batt, 121st Reg:

1st Battalion, 121st Field Artillery Regiment, formerly of the 57th Field Artillery Brigade

As for which company within 1/121 and which truck number? Unknown... You'll have to try and remove the demil on the driver's side of the bumper to uncover that info. Hope that helps!

 

[Zen Diesel]

I would replace the harmonic balancer.
Especially if it’s original.
The rubber on mine was hard and cracked and starting to separate from the Steel.
Not far away from complete failure.

It’s no secret that more than a few 6.2L diesels have broken crankshafts directly related to old and worn Harmonic Balancers.

Acdelco still makes one and it fits and functions perfectly.
Replace your front crankshaft seal while you’re at it.

View attachment 777426

Thanks for the advice. The harmonic balancer is definitely on my list of future projects. But what I was stating with CUCVRUS its a better idea not to get too distracted while I try to chase down the air leaks and take the residential plumbing fixtures out of my fuel system.

I am attempting to replace my mechanical fuel pump but it looks like I have to take the turbo, crossover pipe, turbo exhaust pipe and passenger exhaust manifold off just to get to it. I can barely see the fuel pump with the alternator removed and if I hold my head at a special angle AND hold my tongue in the special way.

While I am at it I am taking notes on other problems I have found on the truck. There is a lot of hack work that has been done on it so I am trying to take care of those problem(s) first while I have half of the engine accessories and exhaust pulled out. As a for instance, a pyrometer was installed on the truck using door bell wire, wire nuts and dollar store electrical tape. All of the wires for my modifications to my truck (boost gauge, pyrometer, tach etc...) were routed through a "rat hole" that looks like it was gnawed through the firewall with a spade wood working bit and no grommet was placed to protect the wires.

The list goes on. Some of this stuff is easier to address now than putting it off so I'm doing that. Its been tempting to try to fix a bunch of things at one time and the harmonic balancer is one of those things [on my bomb proofing list]. As another example I just found the source of 2 of my coolant leaks and I am a little concerned I may have a blown head gasket that has caused the leaks so before I go too far down the rabbit hole on this particular engine I am going to keep my focus on getting the fuel system sorted and the truck started. The deleted CDR has caused a bunch of other problems (oil blowing past the seals on the turbo) rear main leak and the entire oil pan "seal" is leaking so right now my 6.2 is leaking like a cummins. I think the oil pan issue is because the wrong rtv was used and the pressure in the engine took one of the easiest paths out. Not sure. Still investigating and learning. Right now I am cursing in languages I don't speak trying to get these exhaust manifold bolts out and looking up parts numbers so I can order the missing hardware for my turbo (the hack that put it in only put the bolts in that you could see) and replacement bolts for my exhaust manifold for the Banks manifold since it is different than the OEM part.

I'm also re-routing the wiring for my second alternator away from turbo exhaust pipe and re-routing and heat wrapping my glow plug wires on the passenger side. I had planned to go through all of this stuff eventually but again some of its easier to tackle now and just slow down my desire to crank the engine. The more I dig into this truck the more I see things that need to be corrected either because they are hack work or for future reliability.

I love off road camping (I can't call it overlanding its camping not a safari) so these are some peace of mind things for me. Having the fuel problem has been a kind of blessing I didn't expect. It forced me to diagnose the problem and get to learn the truck from the bottom up. I can't wait to get it on the road.

 

[Zen Diesel]

NG1EZ3 or NG1EZJ should be your registration number, and it should match the reg number on the data tag in the driver's door jamb... I say "should", because sometimes data tags disappear, or perhaps your truck got another truck's brush guard at some point along the journey.



Modern army unit marking should describe: Command<>Brigade<>Battalion<>Regiment<>Company<>OrderOfMarch

The first photo of the passenger's side bumper seems to show 57BDE-1-1, but there also appears to be the faint bottom half of a "2" after the second "-1"...which would jive with the 1/121 above the driver's door handle in the third photo. So that gives us the Brigade (abbreviated as BDE) thru Regiment of 57BDE-1-121, which translates to 57th Bde, 1st Batt, 121st Reg:

1st Battalion, 121st Field Artillery Regiment, formerly of the 57th Field Artillery Brigade

As for which company within 1/121 and which truck number? Unknown... You'll have to try and remove the demil on the driver's side of the bumper to uncover that info. Hope that helps!

Wow thanks that is really helpful, I am going to try to see about getting that drivers side bumper paint off! The original paint is showing signs of age and eventually I would like to repaint the truck with its original markings so that will be helpful when I am asked what the history of the truck is.

Thank you for the info!

 

[Tinstar]

Thanks for the advice. The harmonic balancer is definitely on my list of future projects. But what I was stating with CUCVRUS its a better idea not to get too distracted while I try to chase down the air leaks and take the residential plumbing fixtures out of my fuel system.

I am attempting to replace my mechanical fuel pump but it looks like I have to take the turbo, crossover pipe, turbo exhaust pipe and passenger exhaust manifold off just to get to it. I can barely see the fuel pump with the alternator removed and if I hold my head at a special angle AND hold my tongue in the special way.

While I am at it I am taking notes on other problems I have found on the truck. There is a lot of hack work that has been done on it so I am trying to take care of those problem(s) first while I have half of the engine accessories and exhaust pulled out. As a for instance, a pyrometer was installed on the truck using door bell wire, wire nuts and dollar store electrical tape. All of the wires for my modifications to my truck (boost gauge, pyrometer, tach etc...) were routed through a "rat hole" that looks like it was gnawed through the firewall with a spade wood working bit and no grommet was placed to protect the wires.

The list goes on. Some of this stuff is easier to address now than putting it off so I'm doing that. Its been tempting to try to fix a bunch of things at one time and the harmonic balancer is one of those things [on my bomb proofing list]. As another example I just found the source of 2 of my coolant leaks and I am a little concerned I may have a blown head gasket that has caused the leaks so before I go too far down the rabbit hole on this particular engine I am going to keep my focus on getting the fuel system sorted and the truck started. The deleted CDR has caused a bunch of other problems (oil blowing past the seals on the turbo) rear main leak and the entire oil pan "seal" is leaking so right now my 6.2 is leaking like a cummins. I think the oil pan issue is because the wrong rtv was used and the pressure in the engine took one of the easiest paths out. Not sure. Still investigating and learning. Right now I am cursing in languages I don't speak trying to get these exhaust manifold bolts out and looking up parts numbers so I can order the missing hardware for my turbo (the hack that put it in only put the bolts in that you could see) and replacement bolts for my exhaust manifold for the Banks manifold since it is different than the OEM part.

I'm also re-routing the wiring for my second alternator away from turbo exhaust pipe and re-routing and heat wrapping my glow plug wires on the passenger side. I had planned to go through all of this stuff eventually but again some of its easier to tackle now and just slow down my desire to crank the engine. The more I dig into this truck the more I see things that need to be corrected either because they are hack work or for future reliability.

I love off road camping (I can't call it overlanding its camping not a safari) so these are some peace of mind things for me. Having the fuel problem has been a kind of blessing I didn't expect. It forced me to diagnose the problem and get to learn the truck from the bottom up. I can't wait to get it on the road.

Absolutely!
Tackle one issue at a time.

 

[nyoffroad]

Just an FYI, door bottom patch panals are made to fit OVER the existing door skin. I always cut the rust out when useing them but only used door bottoms as a last resort like on a 56 Buick. By the time you buy the panels and cut weld and do all the bondo work even to a semi exeptable state for flat paint your going to have a lot of time and work into them. Have you ever checked the price and availabilty of after market doors? The CAPA certified doors (if available) fit very well and will last years longer then a welded on door bottom. Even non-certified doors would be better.

 

[Zen Diesel]

Absolutely!
Tackle one issue at a time.

Thanks! As I discover new issues that is my mantra, a little chuckle and “one problem at a time”. I’m taking notes and lots of pictures so I don’t have to try to remember everything that needs addressing. I enjoy wrenching but honestly I am a little anxious to fire it up. I need to get it in the garage so I can work indoors in the heat hands get crampy otherwise.

 

[cucvmule]

One thing about Detroit Diesels, they are easy to work on and maintain once you understand the basics of operation. They are dependable and as long as you keep the fuel system tight, airless. Start and operate on a monthly schedule to keep seals pliable and that will reduce repairs also.

Taking the wheel well covers out will make some work easier and the fuel line at the frame to the firewall, rubber hose will need to be replaced anyway. So that will make the fuel pump replacement a little better to do. And I have a habit of using antiseize on body bolts, fender bolts, anywhere that rust can lock them up tight. The sheet metal bolt clips do not last forever but last longer if the paste is used. Exhaust bolts and antifreeze bolts, studs, glowplugs can last longer and are removed easier by the use of antiseize.

And you are spot on by their are a lot of worse habits. Stay lighthearted.