2nd fuel tank installation 1985 M1028

[Greenhorn]

I'm considering installing a 2nd fuel tank(rt side). The rt side has been damaged where the angle mounts had been and am thinking about replacing rt bed side. If I do I'll get one with a fuel door. Here is the question. Does anyone know how to and what is needed to plumb the 2nd tank in? I have a 82 1/2 ton gas parts truck with duel tanks but don't think the installation is the same for gas and diesel. I also have a m1008 that I can rob it's tank. As always, thanks.

 

[Crash_AF]

My 1985 Chevy dealer parts manual shows only two part numbers for the tanks, a 16 gal and a 20 gal. No separate part number for left and right or gas and diesel. The only thing that's different is the fuel level sensor. These are gas and diesel in addition to side specific.

I am trying to figure out if the filler neck itself is the same left and right. You might want to pull the two out of the donor gas truck and compare the two necks, if they are the same, you can pull the one out of your 1008. Otherwise you're going to have to find a diesel specific right filler neck or punch the unleaded flapper out of the one you have so the diesel nozzle will fit.

Oh, and take lots of pictures.

Later,
Joe

 

[Greenhorn]

Crash,
Thanks for the info. I plan to use the tank and sending unit as well as the filler neck assy from the 1008. So, as you see it, the plumbing is the same on both gas and diesel installations? What is different with the fuel level sensor and will I need to chg entire assy or just sensor?
Thanks, Green

 

[Crash_AF]

The entire assembly, the fittings point a different direction.

The actual hoses are different too I think, it's just the end that bolts to the bed that's the same (I think). Again, pull the left and right fillers off the gas truck and see if they're the same. If they are, then you can use the ones from the 1008, otherwise you're going to have to mix n match between the 1008 and gas truck. Either way, you're going to have to buy the right side sending unit for a diesel.

I don't know what the exact difference is between the gas and diesel senders, I suppose you could try the gas one and see if it works, but I dunno what problems that might cause down the road.

Later,
Joe

 

[jj]

My experience on a '79 one ton was that the tanks AND the brackets that hold the tanks are interchangeable. The truck was a chassis cab with dual wheels and came with a single tank on the right side. I scrounged another 20gal. tank from somewhere and it fit perfectly on the left side. Later, that left tank leaked, the right side floor needed rust repair, so i moved the original right side tank and relocated it to the left side so i could weld on the rust repair on the right side. There were no fit issues. But, the truck was a chassis cab from the factory, with an aftermarket flat bed. I don't know how the pick-up bedside fuel fillers might affect this. My plumbing on the fill sides and the pump sides was very "homegrown" and probably wouldn't bear examination for your purposes.

 

[Recovry4x4]

Rather than going through all the switching stuff, I'm going to use the right tank as a transfer tank and just pump fuel from that tank to the left tank with a simple pump.

 

[firefox]

This sounds like a good idea. are you still going to set up a fill access, or are you just going to
fill the left tank, then transfer to the right tank and then refill the left tank?
Bruce

 

[wallew]

Back in 'the day', the Chevy's came with a 't-fitting' that allowed you to switch from one tank to the other. When you did that it changed the fuel flow from one tank to the other. Then you just flipped a switch that changed which tank was being read on the dash fuel gauge. The BEST thing about that 't-fitting' is if you turned it to the middle setting you got NO FUEL. Pretty good theft deterrent device, stealthy even. There's just about enough fuel in the lines to let some boob start it up and MAYBE get out of your driveway before it stalls, leaving the thief there for either YOU or the cops to deal with.

I have been considering a right side tank with the fuel filler sticking out of the wheel well. Plus another forty gallon at the rear that the filler neck would also come out at the rear wheel well. I could theoretically could carry 80 gallons. I will add a fuel pump for each tank so fuel delivery won't be an issue regardless the terrain or tilt of the chassis, it will always get at least 6 psi worth of fuel. That way I don't have to use the same fuel pump for three different tanks. And I'll have to mount the spare tire in the bed of the truck. Actually I'm mounting two spares in the bed of the truck.

 

[Recovry4x4]

My plan is to rig a filler inside the rear fenderwell and fill it there.

 

[WARWAG]

I searched and found this thread. I too am planning on a dual tank and have found that both tanks either side have the same part number 2050A. Short bed trucks had 16 gallon tanks and long beds had 20 gallon tanks. 2050A is for the 20 gallon tank. Thats as far as I have gotten. I would like to plumb it in as the factrory did since I want to use the second (passenger side) as a veggie oil tank. Does anyone have a parts list needed to complete such a mod?

 

[Darwin T]

i am on the lookout for a M1028 and i also want to add a 2nd fuel tank. to increase range and ballance the load. was the t valve that cut fuel in the middle a chevy factory piece?

 

[jj]

There was a factory valve for selecting one tank or the other, of course. The last one i bought was dual circuited, that is, it had six ports to accomodate the fuel supply and return lines. In operation the fuel pump drew from and returned fuel to the same tank. This didn't require operator involvement in remembering which tank was full or empty. I found a part number at compnine for this selector valve for a 1987 R-3500. This would be the same body style as the M-1008, i believe. Try 14029228. In the drawings (which ARE the GM parts book drawings) on that website, the part appears to be what i used. The last one i bought was less than $20 American. Compnine says the current GM list price is $180 and some change! WOW! is all i'm gonna say about THAT. There has to be something aftermarket less expensive, even if you had to use multiple valves to make the supply and return plumbing work as intended.

 

[OL AG '89]

My son and I just finished with R&R of both fuel tanks on his '79 K20. LMC had all of the parts. Switches, fuel valve and rubber lines. Don't remember the prices, but had to be done .....

 

[skysix]

Anyone added a blazer or suburban tank in the rear (after removing the spare and crossbar that it hangs from)? Thinking of doing that and making it the primary tank, filled by a transfer pump from the left and right tanks.

 

[DTL]

I'm in the process of adding a second tank to my '84 M1008. I wasn't planning on doing it, but I found a replacement bed (my original was hammered) that had the right side fuel door. I ended up scoring the right side tank, filler and brackets in the deal so I can run both tanks and not have to abandon or cover/fill the unused fuel door. I'm using an aftermarket (pollak) 6-port fuel tank selector valve. I've used them before on several other projects and had good luck with them as far a reliability and durability. The switch the tank sending unit signal along with the feed/return lines so your fuel gauge will accurately report the level of the tank you're running on. I'll try to post a few pictures once I get the right hand tank hung.

 

[WARWAG]

Im heading to the junk yard tomorrow to see if I can score a dual tank bed. If not I may just have to cut me some fuel door panels off the sides of two beds. I want one for a 3rd rear mounted tank since I wont have a spare I might as well have another tank.

 

[DTL]

I thought about doing a rear mounted tank too, until I stumbled across that bed. 3 tanks, now that's just greedy!

 

[skysix]

Greedy - not with #2 diesel at current prices! On the other hand 71 gallons purchased wherever the closest cheap bulk dealer is should cover the cost of the extra miles needed to drive there and less of them as well since 3.5 times more capacity!)

Northwest Metal Products here in Oregon makes a 42 gallon right side tank (if you have a ingle muffler exhaust on the left side of the driveshaft only) or 27 gallon left and right side tanks. They also make a 45 gallon suburban tank. Pricey though.

Better have an A2 or A3 if you're loaded and fuelled with 114 gallons!

 

[WARWAG]

Will that 45 gallon suburban tank fit were the rear spare tire is on the M1028? Or is it strickly a Suburban item?

 

[skysix]

They say it's Suburban only - but I think if you remove the brace the spare hangs from it might fit. Will PM a sketch - you'll have to measure up your rig and get back to us...