She Ain’t Purty … Yet: Installing an External Fuel Tank in a 67-72 Chevy C10

Day 11:

For some reason, the early Chevy C10 pickup trucks had an internal fuel tank.  Internal as in inside the cab.

The problem with mine was that the internal tank leaked.

Add 10 gallons of gas? Prepare for seepage about 2/3 from the bottom, and gas fumes? Most unpleasant.

The solution: An external gas tank mounted behind the rear axle.

The Parts:

Three items from LMC Truck are pictured above:

LMC part number 32-5929 Gas Tank Kit 17 Gallon (includes the fuel gauge sending unit, seal and tank mounting straps)

LMC part Number 32-3352 Filler Hose – 4″

LMC part number 32-5800 Fuel Filler – Polished – Keyed

Not pictured are:

A Fuel Neck Filler Panel (also from LMC Truck)
Two lengths (60″ and 6″) of 3/8″ steel fuel line tubing.One “standard Chevy” in-line fuel filter
18″ of flexible rubber fuel line
Four 1/4″ – 5/8″ circle clamps
Four sets of bolts, washers, lock washers and nuts in both 1/2″ and 3/8″ sizes.

The picture above also shows the top cross-bar for the spare tire mounting bracket (across the tank).

Step One is to remove the spare tire mounting bar.

I used a cutting wheel on a Milwaukee 4-1/2″ Sander/Grinder (Model 6148-6) to shave off the bottom of the rivets.  A hammer and chisel applied to the top of the bar and the rivets popped loose.

Step Two was to position the new tank into the frame and verify the the filler tube will exit the bed floor at the right location.  To do this,

I supported the tank into position with a large box and an assortment of boards to achieve the right height.

Next,

I measured to mark the center point between the floor mounting strip bolt holes and aligned this point with the center-line of the gas tank filler tube.

And marked the centers for drilling 1/2″ mounting bolt holes.

Step Three was the drill the 1/2 mounting holes into the frame. After drilling, tank was attached to frame with four 1/2″ bolts and measurements were taken to verify placement and wonder if the mounting straps are really necessary?

Step Four was to preform the mounting straps by bending to fit the tank and contact points on the frame.

I used a piece of flat bar with holes to make a template for bending the mounting straps.

I then lowered the tank and placed the bent mounting straps to check the fit.

Step Five was to drill the holes for the mounting straps. The tank was then re-installed with the mounting straps secured at each end with 3/8″ bolts. The 1/2″ bolts were reinstalled on the sides.

Step Six was to install the fuel sending unit and filler cap and hose.

Step Seven was to route the new 3/8″ fuel line and in-line filter.

The final steps needed are to attach the ground wire for the sending unit; remove the old tank from inside the cab (and re-route the gas gauge wire to the new sending unit); locate a tube and check-ball valve for the tank vent.

Including a trip to The Home Depot for bolts and the auto parts store for fuel lines and filters, this took me just under eleven hours to complete. It will be worth every minute to have the gas fumes out of the cab!