Thread: Series 3 Auxilliary Tank

Basically you drill out the spot welds on the front and outside of the base of the seat box then follow the seam up the front and between the outer and middle seat etc. If it is an army LHS tank it will only be 10 gallons (aprox 45 litres). You then need to make a chassis bracket that welds to the side of the chassis and holds the front of the tank. I would be doing the tank project with a second 16 gal (70 kitre) RHS tank and merely fit it on the LHS, that way the chassis bracket is merely a length of angle welded to the back of the chassis outrigger under the firewall. It is a much simpler bracket and gives you 6 more gallons (25 L) of fuel making a total of 140 litres.

In a 1976, I think you will find that an underseat fill is illegal, so you need to plumb the filler neck to the side the same as the fight hand filler neck. If you cant find the rubber for the LHS, get a RHS one, cut the tube in the middle mid-way between the two bends, get a short length of appropriate sized metal tube (exhaust pipe is good) insert it where you cut the tube and rotate the bottom to make a LHS filler tube and clamp up with jubilee clamps.

As Diana says. If all the bolts are easy to undo, I would be inclined to remove the seat box for the job.

John

Originally Posted by Lotz-A-Landies

Basically you drill out the spot welds on the front and outside of the base of the seat box then follow the seam up the front and between the outer and middle seat etc. If it is an army LHS tank it will only be 10 gallons (aprox 45 litres). You then need to make a chassis bracket that welds to the side of the chassis and holds the front of the tank. I would be doing the tank project with a second 16 gal (70 kitre) RHS tank and merely fit it on the LHS, that way the chassis bracket is merely a length of angle welded to the back of the chassis outrigger under the firewall. It is a much simpler bracket and gives you 6 more gallons (25 L) of fuel making a total of 140 litres.

In a 1976, I think you will find that an underseat fill is illegal, so you need to plumb the filler neck to the side the same as the fight hand filler neck. If you cant find the rubber for the LHS, get a RHS one, cut the tube in the middle mid-way between the two bends, get a short length of appropriate sized metal tube (exhaust pipe is good) insert it where you cut the tube and rotate the bottom to make a LHS filler tube and clamp up with jubilee clamps.

Thanks Lotz-a-Landies, Much appreciated. I've checked my machine out using your description and it appears that my toolbox is entirely supported by pop rivets and a few bolts, so the job will be much easier than I had thought.
I understand your comment about the larger tank, but the 45 litre one will give me enough range. I've already acquired a second RHS fuel inlet system, so just need to modify it as suggested to hook it into the tank.
The aim is to simply plumb the tank through a change-over tap (probably located behind the driver's legs on the kick plate, but I haven't checked this out yet). I won't bother with a gauge, I'll just reset the trip meter when I switch to that tank as it will mostly be used on highway stages when consumption can be guessed at with fair accuracy to predict when it will run dry.
Thanks again,
Cheers,

Coop

Originally Posted by Lotz-A-Landies

Basically you drill out the spot welds on the front and outside of the base of the seat box then follow the seam up the front and between the outer and middle seat etc. If it is an army LHS tank it will only be 10 gallons (aprox 45 litres). You then need to make a chassis bracket that welds to the side of the chassis and holds the front of the tank. I would be doing the tank project with a second 16 gal (70 kitre) RHS tank and merely fit it on the LHS, that way the chassis bracket is merely a length of angle welded to the back of the chassis outrigger under the firewall. It is a much simpler bracket and gives you 6 more gallons (25 L) of fuel making a total of 140 litres.

In a 1976, I think you will find that an underseat fill is illegal, so you need to plumb the filler neck to the side the same as the fight hand filler neck. If you cant find the rubber for the LHS, get a RHS one, cut the tube in the middle mid-way between the two bends, get a short length of appropriate sized metal tube (exhaust pipe is good) insert it where you cut the tube and rotate the bottom to make a LHS filler tube and clamp up with jubilee clamps.

If you do use a piece of metal tube between two pieces of rubber tube, just be careful to earth the metal tube to dissipate any static charge build up.

Originally Posted by C00P

... I won't bother with a gauge, ...

Coop

If it is an ex-Army tank it likely already has a fuel level sensor, if it is one of the late SIIa sensors, (will look the same as your original tanks sensor) it is already compatible with the guage in your SIII. All you need to do is get a change over switch, two position if you can get one, otherwise a three position centre off. (On-Off-On)

The center terminal goes to the guage on the dash, then the original fuel tank wire goes to the terminal at one end and you run a new wire from the tank sender to the terminal at the other end of the switch.

Originally Posted by Lotz-A-Landies

Coop

If it is an ex-Army tank it likely already has a fuel level sensor, ....

No it doesn't, but it has the hole where the sensor would fit. I'll think about having a sensor fitted if the change-over switch is that easy to arrange.

Thanks for the info,

Coop

EASIEST WAY TO SEE IF EX MIL ... DOES IT HAVE A DIP STICK?

Originally Posted by digger

EASIEST WAY TO SEE IF EX MIL ... DOES IT HAVE A DIP STICK?

Nope. It Doesn't. After market, maybe?
Landyauxtank.jpg
The white circle covers the fuel level sender hole. The object in front of the filler neck is a dust cover.
Got the seat base out tonight. Got some cleaning up to do, but so far, so good.

Coop