saddle tank questions

[veltex]

Do steel fuel tanks need to be treated inside? Does gasoline have anti rust stuff in it? My pickup (68 c20,396)has saddle tanks that I would like to start using (havent been used in years) , I want to have the the filler necks relocated to the inside of the rear fender wells, and will need to have them cleaned before they can be welded on, they look to be dealer add ons(?) just plane steel boxes maybe 15+ gallons each, with a 3way valve in the cab, no senders. So, my dilema is to try to get by with what I've got, on a budget, new aluminum saddles would be a great option but spendy, any thoughts?

[68C15]

you could either;
A. remove tanks & have a radiator shop clean & seal them
B. buy stock in a fuel filter manufacturing company
as far as gas having a anit-rust it is the excact opposite. fuel containing ethanol will remove rust over time & plug filter just when you need it most.
also dont forget about the "varnish" that may well be in there also.
if you want to know the fuel level in tanks that would be easy using a single pole triple throw toggle switch on the brown wire going to senders.

[walker]

After having them cleaned and your new necks put on use a fuel tank sealer kit. It is just some goo that gets sloshed around in the tank and dries, kind of like spray bed liner stuff. As far as the fuel level goes, you fill all three tanks, run on a saddle tank till it runs out, switch to the other saddle tank till it runs dry, than switch to your main tank, which has a gauge.

[lewi]

I have the saddle tanks and relocated the fillers also. The existing fuel gauge sender in each tank will operate the fuel gauge. I took the saddle tanks that hadn't been use in years to a radiator shop for cleaning and installed them, not being much of a mechanic had an electric selenoid installed that switches between tanks with the flip of a toggle switch mounted below the ignition switch in the cab. When the selenoid changes from tank to tank the fuel gauge then reads the fuel level in the tank that is being used. I removed the in-cab tank and have had no problems. .

[vincep]

What do these saddle tanks look like?

[mrein3]

When I bought my truck it had one saddle tank on the drivers side. It leaked. The previous owner said fill it before a long road trip and use it up then switch to the seat tank with the gauge.

I didn't like this setup so I tried to remove the saddle tank. The original fasteners on the bottom of the tank were rusted solid. So I ground off the heads of the long carriage bolts in the bed and lowered the tank to the ground. Be prepared to whack the bolts out with a sledge hammer. Mine were really rusted/mudded in there. Also be prepared to then spend some time cleaning out the holes.

For $50 I had a shop solder the leak shut and coat the inside. I then purchased a JC Whitney sender and gauge and mounted the gauge knee-knocker style.

Since I ruined the original fasteners I just bought some short 1/2 inch carriage bolts and a couple of feet of 1/2 inch threaded rod. I MIG welded the carriage bolts to a piece of the threaded rod long enough to reach throught the tank. The tanks have 1 inch or so pipe that goes through the tank for the bolts to reach through. I just used and ordinary fender washer, lock washer, then nut on the bottom of the bolt to hold the tank up. It has been that way for a couple of years now.

Oh yeah. I also por-15ed the outside of the tank after I got it back from the shop. It should be good for another 30 years.

In the picture the temp gauge is for my automatic transmission I installed in place of the original 3-speed manual. The toggle is for my back-up lights which disengage the brakes on my boat so I can back it in. Then finally the fuel gauge for the saddle tank from JC Whitney.