door 109 Land Rovers come with a single 12 gallon fuel tank under
the right front seat. There is a tool box under the left front seat.
Rather than mount Jerry cans outside the body where they raise
the center of gravity and are very vulnerable to impact, I decided
to add a fuel tank under the front left seat.
The factory mounted an auxiliary fuel tank in the same location
when they built short wheelbase Land Rovers with dual fuel tanks.
The auxiliary tank has the filler cap attached directly to the top
of the fuel tank. You need to remove the bottom cushion of the front
seat and fill this tank from the inside.
I elected to add a tank that can be filled from outside the car.
My shopping list
I purchased all the parts for a front right fuel tank and filler
assembly including the mounting fixings.
Since the auxiliary tank is a popular option, I was able to purchase
a front left fuel tank outrigger that was ready to be welded to
I purchased a four inch length of two inch diameter steel exhaust
tubing and two hose clamps.
I am using several MGB gauges in my Land Rover. I purchased a second
fuel gauge and a series III sender unit for the new fuel tank. I
purchased a brass fuel selector valve and additional fuel hose from
my local auto parts store.
A critical part of the project was creating a template for making
the hole in the left side of the car. Since my filler assembly was
purchased used, I drew a template on a sheet of paper from the hole
left by the removal of the filler I purchased.
When I drew the outline of the hole, I was very careful to mark
where the body crease was located. This allowed me to vertically
place my template on my car. I measured the distance from the back
of the door opening to the edge of the hole. This provided me with
the horizontal location.
This picture shows the filler for the new left fuel tank (left)
and the 15 gallon water tank (right)
Mounting the tank
First I made the necessary holes in the car. I always find this
to be traumatic. Using my template, I cut out the hole for the filler.
I fitted that in place then drilled the holes for the mounting rivets
using the actual part as the template. I went ahead and pop riveted
it into place. Next I screwed the metal filler tube into place.
The project looked completed from the outside.
Next I cut out the hole in the front right seat box. I measured
the frame spacing on the front right tank, and the dimensions of
the new fuel tank then cut the box. There was a little storage space
left inside the toolbox where I now store containers of fluids for
I checked the hole size and location by offering up the new fuel
tank and lining up the rear mounting holes. This also allowed me
to mark the location for the filler hole behind the seat box.
I cut the filler hole to the same shape as the corresponding hole
on the other tank. I fitted the tank adding bolts to the rear mounts
and propping the front up in its proper location to assure proper
fit. When I was sure that the holes were properly located, it was
time to add the front frame outrigger.
I had a welder perform this step. He offered up the fuel tank,
adding two rear bolts, bolted the new outrigger on top of the front
fuel tank mounting flange (The tank mounts to the underside of the
outrigger) and marked the location for the front outrigger. After
removing the fuel tank he welded the outrigger in place. The weld
The new fuel tank was bolted into place using all the fixings.
This left the filler hose to connect the tank to the outside filler.
I cut a new filler hose in half at the middle of the straight section.
I inserted the four inch steel tube between the two halves effectively
extending the tube about an inch and a half. Next I mounted the
filler hose to the tank and filler tube, adjusting the length at
the middle cut. When it was in place I tightened down all four hose
clamps then added the breather hose.
I placed the second MGB fuel gauge into an auxiliary panel under
the first. One wire was connected to the voltage stabilizer previously
installed for the other MGB Smiths gauges. The other wire was routed
to the series III sender unit. I also added a ground line from the
ground lug on the sender unit to the chassis.
I mounted the fuel selector valve on the front of the seat box
between the two front fuel tanks. I routed hoses to the valve from
both tanks and the fuel pump.
I filled the tank and drove off.
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