CUCV fuel tank replacement

[Mastiff]

Okay, so my tank straps on my 86 CUCV were rotted through, so dropped the tank to replace them. Turns out the tank is rusted through also and started springing leaks when I wire wheeled it.

So I ordered a new tank fom gastanks.com, plus new straps from LMC. Also tank vent and filler hoses since I had to cut them apart to get the tank down (clamps rotted).

I'm all ready to install everything today, and first thing I notice is that there is no way in heck that the filler hose will fit. The one from LMC is the same diameter on both ends, but my original is much bigger on the filler side. LMC doesn't list a different part for diesel or anything, is this a CUCV thing? For now I have my old one siliconed and duct taped until I find a better solution.

Next thing is the straps. I ordered the set from LMC, and they are both the same length. Looking at the tank, the front one has much less distance to cover than the back. Is this right? I mean, the same length straps? If so, what's the trick to getting the back one to reach? I'm pulling with all my might and I can't get it to reach around. It's about an inch short. Do I have to hammer the seam in on the side of the tank or something?

TIA.

 

[Mastiff]

I can just barely get the strap to reach if I remove all the felt padding stuff and put a nut on the inside part of the threads on the strap so I have something to grab onto with channel locks. With the felt in there, I got it to reach once by using the channel lock trick, but it's super tight and it's only grabbing by a few threads. Any ideas?

The nut I'm prying with is the one from the other side, so I have to take it back apart anyway.

 

[dyeager535]

OK, looking at the '86 fuel tank/sending unit application chart in the parts manual, there are only two fuel tanks listed for a K5, period.

14050685 94 litre tank.
14050684 117 litre tank.

Diesel and gas are the same part number.

Don't ask me why, but '685 says "(6.2c,j) (exc. 40gal ne2, 31 gal nk7)
and '684 says "(602c,j) w/31 gal (NK7)

I wonder why the 40 gallon isn't listed. I suspect bad info in manual.

The tanks are listed for both the suburban and the blazer, so the small one must be the 25 gal. It *appears*, that at least for '86, the suburban with 6.2 could not have a 40 gallon tank. I'm not saying that is truth, just what the manual indicates.

I'd be interested in bouncing those numbers off of a CUCV parts manual.

All the M1009 tanks I've seen in service are NOT 31 gallon, whatever size the military calls them. They are nowhere near the bottom of the skidplate. They may be service replacements, but it's not been only one or two that I've looked at. There are only two K5/burban skidplates listed for '86, 31 or 40 gallon. Only lists two different straps, 31 or 40 gallon. Again speculating based on the parts manual, that means in 1986, only 31 gallon tank was available in K5's whether diesel or gas.

 

[Mastiff]

Damn, sorry to send you down the wrong track, this is for a CUCV pickup, M1008. So my problem is with the driver's side tank, not a center rear.

I eventually got the strap to reach by removing most of the anti-squeak stuff and then finding a spare nut to put on the threads to squeeze against with channel locks. Pretty friggin ridiculous if you ask me, they could just make the strap an inch longer and the job would have been a cake walk.

 

[rugger03]

how many gallon tank is the replacement? stock on a m1008/1028 is 20 gallons, but that shouldnt matter since you got new straps.

I believe the problem with the filler neck might be unique to the CUCV's and not all diesels the civilian diesels i have seen have a small standard size opening, while CUCV's have the jumbo opening. I'm guessing its becuase they have to be able to get fuel from the all in one fuel stops the militray sets up.

 

[sweetk30]

first if the new tank hasnt had the seam bent down flat on the sides it will be a pita to get straps on. and second the smaller one 15 gal can go in where the 20 was on most trucks. just move to the other holes , but who wants less capacity.

 

[Mastiff]

how many gallon tank is the replacement? stock on a m1008/1028 is 20 gallons, but that shouldnt matter since you got new straps.

I believe the problem with the filler neck might be unique to the CUCV's and not all diesels the civilian diesels i have seen have a small standard size opening, while CUCV's have the jumbo opening. I'm guessing its becuase they have to be able to get fuel from the all in one fuel stops the militray sets up.

Yeah, I got a 20 gallon replacement. It looks identical to the original minus the rust. Well, plus that the seam part sticks down at only a 45 degree angle or so where the original was more flat against the tank body. I think that was part of my problem, plus I wanted to put the anti-squeak stuff in there and it takes up space.

 

[sweetk30]

flatten the seam and it will fit much easyer. and to bad you are so far away. i have two comlete setups ready to go 1 left and 1 right. i will let go cheep.

 

[Peglegwillie]

Doing same thing with my 86' M1009. Except not rusted but full of crap! Just as costly to have cleaned and repaired than to replace. Have received new tank , straps and sending unit from LMC truck comparison looks the same will find out during installation. Hope all goes well will file report after completed!
Also installing newer better electric fuel pump with filters mounted before and after to replace ones used !

 

[diesel4me]

You could probably use a hunk of hose that fits the new tanks smaller filler neck tight as a bushing to take up the extra space,so the filler neck hose fits snug...
I've had to do that on radiators before,when the one I got to replace an original had smaller hose size outlets on the upper hose..