Aux. Gas Tanks

[GMC_man]

Looking into buying one of these truck, cause there so awsome, But have a few gas tank related questions. I'v seen the long beds with the steel square door on the side and have been led to belive these are factory installed aux. tanks. I'v also herd these aux. tanks where offerd on both left and right configerations or both(for a totaly of three tanks). Just wondering if anyone know's anything about these tanks such as was it availbe on short beds and could you get it on both left anf right sides for a total of three tanks if desired? also what years where these availbe all years?

Thanks, and sorry about the spelling

[WorkinLonghorn]

Don't know about the short beds but I've seen tons of 3-tank long-bed trucks and I believe the extra ones were added on by the dealer. I have three tanks but can only afford to fill one!

[special-K]

The auxilary tanks were available left/right and for any Fleetside or Blazer,also an aux.was available for Suburbans.They were aftermarket and anyone could install them.Many had dealers upfit when new.In`72 GM offered an auxilary tank in longbed Fleetsides on the driver side with a filler up near the top of bedside.

[Longhorn Man]

there were dealer installed units like you just described, and then there were stock aux tanks.

[hdflstf]

Here's mine with what I understand to be a factory aux tank.

[special-K]

That` a nice GMC.That`s the factory tank I described and only available in`72.

[hdflstf]

Originally Posted by special-K

That` a nice GMC.That`s the factory tank I described and only available in`72.

Thanks. It is a '72.

[YellowDog]

Nice timing on this post...I just bought a 71 Custom Camper/20 w/ 3 tanks. I haven't fiddled with it yet, but which switch position corresponds to which tank? I assume straight up is the main tank, but how about the right/left tanks? I've learned a lot on this forum, so thanks everyone!

[GMC_man]

Thanks for the replys, Anybody know if you can buy repo parts for the three tanks, i havn't seen anything out there on the net other then adding one in the back between the rails. so is it possible to put 2 aux tanks in if i got one of these trucks and it only had one?

hdflstf, where is ur aux. tank located?

later _man

[hdflstf]

Originally Posted by GMC_man

Thanks for the replys, Anybody know if you can buy repo parts for the three tanks, i havn't seen anything out there on the net other then adding one in the back between the rails. so is it possible to put 2 aux tanks in if i got one of these trucks and it only had one?

hdflstf, where is ur aux. tank located?

later _man

In the side yard at the moment

Straight down from the second filler under the bed. I've got some uninstall pix in the "Who Put Paint Thinner In My Tank" thread.
So far, I've located no parts from the vendors. I'm going to make a new gasket for the float assembly and I've found some new 7/16-14 carriage bolts (12") long to replace the badly rusted bolts that were there.

[mrein3]

When I bought my truck the previous owner said the aux tank leaked - use it first.
Well even back when gas was $1.069/gallon I wasn't going to let it go to waste so I decided to pull the tank and have it fixed.

First off the hardware had fused (rusted) together. So I had to grind off the bolt heads in the bed and lower the tank with them still in there.

Then I had to use an 8 pound sledge to get the remaining bolts out of the tank. The bolts pass through a section of pipe, right through the tank. After I got the bolts out I used a drill and other various devices to clean those holes out for an easier install.

The radiator shop I brought it to said that since the tank was made of such heavy material they could fix it. Most 30 year old tanks (I did this 10 years ago) aren't repairable. The soldered it up or something. Then asked if they should 'put a liner in it' which I think means dump in paint like chemicals that cure and seal it. I had that done too.

Then I orded a gas gauge and float from JC Whitney and installed that.

Then I bought a hunk of 1/2"-13 threaded rod and some 1/2"-13 carriage bolts and welded up some long carriage bolts to replace the ones I ground the heads off of.

I used to always run that tank first but now since gas is 4.199/gallon and that gas door locks, I run my seat tank out first. (Gas is cheaper here but some idiot [me] installed a 383 with flat top pistons so it pings with 87 octane).

A couple of years ago I broke the selector handle. It is pot metal and I tweaked it just right and broke it. The next small town over has a hardware store that has stuff on the shelves that is older than me. They had the valve and handle assembly on the shelf. No price tag so he said how does $20 sound? I said perfect.

Regarding which tank is selected by which position on the valve...
Remember these trucks were made and sold when most folks who drove knew a thing or two about the vehicle they drove. There were lots of manual things like this tank selector. You can plumb it to be how ever you want it to be. The only way to know for sure is to look under the valve and follow the lines. The handle points to the selected gas tank feed. On mine I have it plumbed so to use the seat tank the handle points at the seat. To use the rear tank the handle points to the rear. If I turn the handle forward it would select a plugged feed and I would guess rather quickly starve the carb for gas.

[JJA1976]

I wish I could say I had the same luck with my aux tanks. I had two like yours. Ground the heads off and used the 8 pounder like you did with no luck. Then tried to drill them out no luck again. Off to the welding shop, $350.00 later they replaced all four of the pipes and steamed them out, pain in the rearend that is for sure.

[special-K]

For switches,pickups,and sending units type stuff check RV suppliers.That`s who made this type of thing.My`72 GMC system was made by Colorado Liesure Products.Not sure if they`re still around.But,check Coast To Coast.It`s a huge catalog RV shops order from.

Hey hdflstf,what year Fatboy do you have?I have a`90 FLST.Everybody thinks it`s a customized Fatboy.