Adding An Auxiliary Fuel Tank - M1028

combat jump · Oct 9, 2013

I’ve decided to add an extra fuel tank, just as some stock Chevy trucks came with. So far, I know that in factory original dual 20 gallon tank trucks, both tanks are identical, but use side-specific sending units. Also that LMC Truck carries almost all the parts needed. Finally, that my local wrecking yards are a good place to look for parts cheaply (though its more work).

I am going to share a step-by-step installation. It will probably take some time, so please be patient. When done, I hope to have documented a completed “How-To” that anyone can follow.

I started with the filler door. My M1028 has only one on the left side, of course. This is a part that you can’t just “order”. I don’t like the idea of having to fill the second tank from inside the right rear wheel well. I found a dual tank 1984 Chevy K30 at the wrecking yard, and cut out the entire filler door.

I used a battery drill to make pilot holes to start a hacksaw blade. Despite what the photo shows (some fancy hacksaw blade tool), turns out that the teeth wear quickly (used 18, then 24 TPI). The tool only lets you take advantage of a small section of the entire blade. I ended up holding the blade with pliers. I got the door cut out in an hour, with three blades (but wished I had brought more).

Again, there’s no way to add a filler door unless you cut one out of a donor truck. This would have been a good excuse to buy one of those DeWalt battery angle grinders with a metal cut off wheel.

I haven’t decided how to attach the door to my truck yet. Of course I’ll cut a hole first, then maybe just rivet it into place. Or get fancy, and weld it. I’d like to see how others have done this.

readyman · Oct 9, 2013

combat jump said:
I’ve decided to add an extra fuel tank, just as some stock Chevy trucks came with. So far, I know that in factory original dual 20 gallon tank trucks, both tanks are identical, but use side-specific sending units. Also that LMC Truck carries almost all the parts needed. Finally, that my local wrecking yards are a good place to look for parts cheaply (though its more work).

I am going to share a step-by-step installation. It will probably take some time, so please be patient. When done, I hope to have documented a completed “How-To” that anyone can follow.

I started with the filler door. My M1028 has only one on the left side, of course. This is a part that you can’t just “order”. I don’t like the idea of having to fill the second tank from inside the right rear wheel well. I found a dual tank 1984 Chevy K30 at the wrecking yard, and cut out the entire filler door.

I used a battery drill to make pilot holes to start a hacksaw blade. Despite what the photo shows (some fancy hacksaw blade tool), turns out that the teeth wear quickly (used 18, then 24 TPI). The tool only lets you take advantage of a small section of the entire blade. I ended up holding the blade with pliers. I got the door cut out in an hour, with three blades (but wished I had brought more).

Again, there’s no way to add a filler door unless you cut one out of a donor truck. This would have been a good excuse to buy one of those DeWalt battery angle grinders with a metal cut off wheel.

I haven’t decided how to attach the door to my truck yet. Of course I’ll cut a hole first, then maybe just rivet it into place. Or get fancy, and weld it. I’d like to see how others have done this.

I've used one of them hacksaw blade holders... forever. Till about a year ago when I sprung for a battery recip saw.
I laughed at the battery reciprocating saws when they first came out and said who'd ever have a need for them. But after getting one, I probably use it as much as the drill. Home, yard, farm, garage, anywhere, but it eats blades a lot faster than my hand hacksawing.

Recovry4x4 · Oct 9, 2013

I've cut out 2 of these at bone yards. I did a tool thread on the Milwaukee Hackzall M18 powered. I can cut one of these out in less than 2 minutes. This will be a good thread.

combat jump · Oct 9, 2013

Recovry4x4 said:
I've cut out 2 of these at bone yards. I did a tool thread on the Milwaukee Hackzall M18 powered. I can cut one of these out in less than 2 minutes. This will be a good thread.

I pulled the trigger on a DeWalt 20 volt angle grinder with 4 amp batteries and a metal cut off wheel.

I'm heading back to the wrecking yard again this weekend, and I'll make that donor truck my bitch.

combat jump · Oct 12, 2013

Went to two junkyards today. I found a fuel filler neck from a diesel that I will use. It came from a truck missing the bed, so an easy part to remove. Other parts are elusive: All the fuel tanks are punctured to drain when they arrive. I'll have to buy a new tank. I've also decided to buy the tank holding brackets - the ones I've seen were either damaged or badly rusted.

nyoffroad · Oct 19, 2013

To bad your so far away from me, I have a complete tank setting outside that I would've given you.
I put the dual tanks in 2 other trucks and found that useing metal adhesive was the easiest way of fitting the filler door cut out. I did one and got hit about a week later and the adhesive held up better then the rest of the box side!
I just ground the outside of the doner part and the inside of my box side mixed the glue and and used a couple screws till it was dry, then a little bondo.

combat jump · Dec 9, 2013

nyoffroad,

I appreciate thought - thanks!

I've been so wrapped up with work that my tank hasn't got the full attention. Here's what I've done lately: Researched for a tank and sending unit - called LMC Truck because their catalog lists almost exact parts/years that I need. They told me their right side sending unit would not fit my year tank. So I found the parts on O'Reilly's web site, and ordered the tank and sending unit. The Sender appears to be for the driver's side, though, as it points the hoses to the right when installed. I will contact them, and maybe send it back, then post updates when I have progress.
Regards,
CJ.

Csm Davis · Dec 9, 2013

combat jump said:
I’ve decided to add an extra fuel tank, just as some stock Chevy trucks came with. So far, I know that in factory original dual 20 gallon tank trucks, both tanks are identical, but use side-specific sending units. Also that LMC Truck carries almost all the parts needed. Finally, that my local wrecking yards are a good place to look for parts cheaply (though its more work).

I am going to share a step-by-step installation. It will probably take some time, so please be patient. When done, I hope to have documented a completed “How-To” that anyone can follow.

I started with the filler door. My M1028 has only one on the left side, of course. This is a part that you can’t just “order”. I don’t like the idea of having to fill the second tank from inside the right rear wheel well. I found a dual tank 1984 Chevy K30 at the wrecking yard, and cut out the entire filler door.

Again, there’s no way to add a filler door unless you cut one out of a donor truck.

I haven’t decided how to attach the door to my truck yet. Of course I’ll cut a hole first, then maybe just rivet it into place. Or get fancy, and weld it. I’d like to see how others have done this.

Well you can do what I did just swap out the whole bed.

combat jump · Dec 9, 2013

CSM Davis,
That's one way to do it! Not my first choice, though. I'd have to find a bed in decent shape first, then remove and unbolt everything from my M1028, re-drill the holes for the shelter tie down hardware, then paint it. I'll do it in small steps instead. I hope to make progress over the Christmas holiday.
Regards,
CJ

Csm Davis · Dec 10, 2013

combat jump said:
CSM Davis,
That's one way to do it! Not my first choice, though. I'd have to find a bed in decent shape first, then remove and unbolt everything from my M1028, re-drill the holes for the shelter tie down hardware, then paint it. I'll do it in small steps instead. I hope to make progress over the Christmas holiday.
Regards,
CJ

That's exactly what I am doing.

xenocath · Dec 29, 2013

i added the tank, Pollack valve, and wiring then auggered out the filler neck from unleaded to diesel sized from my old 3/4 ton 81 chevy but stupid me forgot to cut out the door before the wrecker arrived so I just cut out a square hole to be filled in the future when a door falls into my lap works well so far with a big American flag magnet to cover it up

TVOLLMER · Jan 2, 2014

I am also considering the dual tank. One question I had was about the fuel return lines. Is there a switch/valve to go in the return lines so they return to the tank being used? Can you use the same style switch/valve as you would for the pickup line?

Csm Davis · Jan 3, 2014

Yeah you have a couple options you can use the stock Chevrolet twin tank setup or the manual valve off of a five ton with twin tanks which is probably the direction I will take because I owned a brand new 83 with the stock setup and it stinks!

TVOLLMER · Jan 15, 2014

Ok thanks. I thought I would have to, but was not sure.

combat jump · Jan 20, 2014

Progress Update...

I cut a square hole into the right side of the bed to accommodate the filler door I had previously sawed out of a donor truck at the wrecking yard. Key point here is to carefully measure the location of the main fuel filler door - the auxiliary door will be the same. I cut a hole just large enough for the donor door to drop in flush. I then marked and drilled the door flange for 1/8" medium length steel rivets. I finished with rattlecan desert tan paint, matching what I had painted the rest of the truck a few years ago.

I had considered welding the door into place, and making it all pretty with Bondo, but this installation is closer to what an ambitious motor pool Sergeant would do, and the rivets look right at home on the CUCV.

The fuel tank is from O'Reilly's Auto Parts. I could not tell if it was galvanized, so I painted it with Rustoleum (with a brush).

The sending unit is also from O'Reilly's. This is a different part from the main tank, as when installed, the tube ends point inboard toward the center of the truck.

The six port valve took some research, as what I found on eBay did not seem to be compatible with a 1985 K30. I found this one on Amazon. The 6 port (five useful) plug was a separate purchase. The selector switch I pulled from a donor Chevy truck.

Ok, that's the update. I'll next be ordering tank brackets form LMC Truck.

-CJ.

Csm Davis · Jan 20, 2014

Like the look of the riveted filler door. What do you mean by only 5 ports are useful?

combat jump · Jan 21, 2014

CSM, looking at both the plug and its receptacle on the valve, you can see that only 5 of the 6 ports have a conductor.

Csm Davis · Jan 21, 2014

Okay thought you were talking about the ports on the valve.

1956_4x4 · Feb 6, 2014

I have to admit that riveting that fuel door on to the bed looks a lot better than I thought it would. I'll be watching for helpful tips.

Smitty

combat jump · Feb 6, 2014

1956_4x4 said:
I have to admit that riveting that fuel door on to the bed looks a lot better than I thought it would. I'll be watching for helpful tips.

Smitty

Thanks, Smitty! I've got the correct brackets, and will be doing some more work in it this weekend. I'll post pictures.

Adding An Auxiliary Fuel Tank - M1028

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