gallon rear petrol tanks came on 109 four door Land Rovers and high
capacity pickups. The two door 109's came with a single 12.5 gallon
petrol tank located under the right front seat. One way to increase
the fuel capacity of a 109 two door without raising the center of
gravity is to add a rear fuel tank.
Mounting the tank
The 109 two door frame already has the rear tank mounting holes
pre-drilled in the rear cross member and the front tank mounting
brackets are welded in place.
However, there were some frame differences that require modifications
to get the tank to fit.
- The second to rear cross member on a two door has a hole for
a rear PTO. The lower part of the cross member bulges down at
this point. The lower bulge was cut off and a flat plate welded
in its place to seal off the cross member and maintain it's strength.
- There was a rear tail pipe hanger bracket that needed to be
cut off the inside of the frame.
- There was a rear flange that needed to be shortened at the right
rear leaf spring hanger.
The rear tank has a rectangular grove along the top to provide
clearance for the second to rear cross member. There is a rubber
tube that goes between the two high areas to equalize pressure.
On the four door models there are two access hatches in the bottom
of the bed. The front hatch provides access to the front equalization
hose connection. The rear provides access to the rear equalization
hose connection, the filler vent hose connection, and the fuel tank
I obtained the access hatch covers from a 109 station wagon being
parted out. I also made measurements of the hole locations and sizes.
There are stiffener ribs on the underside of the bed. Two longitudinal
ribs and one transverse rib provides a resting surface for three
sides of the cover plates.
I cut out the access holes, being very careful not to cut the stiffener
ribs. Next I riveted a sheet of metal to the underside of the fourth
side to create the fourth resting surface.
At this point the rear tank can be mounted to the frame using stock
LR mounting hardware.
The fuel filler
There are a number of ways to set up the filler. The simplest I
have seen is a fitting for a fuel cap welded onto the intake for
the tank, and a hatch door fitted to the side to get access to the
filler. I wanted something that looked Land Rover.
I used the filler system from a 110 Land Rover High Capacity Pickup.
This is a plastic part that fits into the side of the body and holds
the filler. The filler and the connecting hose were also Land Rover
High Capacity Pickup parts.
- First I cut the hole in the bottom of the right rear tool box,
eyeballing alignment from the filler on the tank. I made trial
fittings of the connecting hose to slowly enlarge the hole until
it looked about right.
- Next came the hole in the side of the body. The High capacity
part that fits into the side takes an inverted 'U' shaped cut
that is flat on the bottom. It fits entirely within the rear tool
box. The horizontal lower cut goes at the junction between the
tool box bottom and side.
- I Cut the opening smallish and filed for a snug fit making frequent
trial fittings as I went along.
- I fabricated small aluminum 'L' brackets to hold the plastic
filler against the side.
The High Capacity Pickup filler parts mate properly with the fuel
tank and looks like they came on the car from the factory.
Next, I installed the equalizer hose to the two high spots of the
fuel tank and routed the fuel line to the front on top of the frame
I have a three way brass fuel switch that I purchased from my local
auto parts store. It is mounted on the front of the seat box and
switches among both front fuel tanks and the rear fuel tank.
This installation, along with the second front petrol tank, provided
me with a 42 gallon fuel capacity at frame height protected inside
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