Fitting extended range fuel tanks to a discovery 1

Written by ralph on 15/12/2009. Posted in Vehicle modifications

For our trip to Tunisia, Atlas Overland recommend carrying a staggering 200 litres of diesel.  With the standard disco tank holding 80 and my auxiliary (starter) tank holding 20, I was halfway there.

I didn’t fancy carrying a multitude of jerry cans and so I started to look for another option.  Searching the internet only provided one supplier of extended tanks for the disco 1 and that is Safari-equip.

I spoke to them on their stand at Newark earlier in the year and decided to order one of their 32 litre rear wing, fill-through tanks at £255.

Now I need to put things into context before I go on.  The products supplied by Safari equip are very good and their telephone manner very helpful but I’m afraid they did let me down a bit with regard to service.  It did turn out okay in the end and they were very apologetic and offered an excellent deal by way of compensation.  I shall not go into detail but it meant that I ended up getting a replacement (120 litre) main tank as well as the wing tank.  Giving me a total, on board fuel capacity in excess of 170 litres.

One major failing of these tanks is the fact that they are supplied without any fitting instructions.  This leads to a lot of guess work and trial and error.  Hopefully this article will help anyone else who wants to go down this route.

I found it a lot easier to fit the replacement main tank first.

Firstly, remove the boot carpet, sound insulation, and fuel sender inspection cover.  If this hasn’t been removed for a while be prepared to grind these cross head screws off and replace them and the plastic securing pieces.


You will then need to disconnect the electrical connector, the fuel suction and fuel return (two 14mm spanners).  The sender head fittings are marked with arrows to show fuel direction.  Make sure you mark the fuel pipes (I used a piece of yellow insulating tape on the return).

The fuel sender is secured by a plastic threaded collar.  I tapped this loose with a heavy screw driver and gentle taps with a hammer.  It was quite tight.  The fuel sender can then be lifted out, taking care not to catch the fuel float.

You then need to disconnect the filler and breather pipe under the offside rear wing.  It is helpful to remove the ‘splash guard’ to get access and you need this off for fitting the wing tank anyway so now is a good time.

disco 023

The tank is held in by a supporting plate (guard) which is secured by two nuts and bolts at the front and two bolts (captive nuts) at the rear (17mm socket and spanner).  In my case I had an aluminium tank guard but the principal is the same.  If fitted you must also undo the rear anti roll bar upper brackets (17mm spanner) and swing it downwards.

TIP: I found it helpful to stretch a webbing strap between the anti roll bar mounts to support the tank while I undid the securing bolts.  Once undone the tank needs to be slid out at an angle to avoid the filler pipe, the strap allows this to be done gently and by one person .

It goes without saying (although I am) that you want the tank empty for this.  Despite running the car with the fuel gauge well below empty for several miles there was still about 10 litres in the tank when I lifted it out.  If you have trouble you can siphon any residual fuel out of the tank through the sender unit hole.

This picture shows the new tank next to the old.


The sender unit then needs to be fitted to the new tank.


At first I didn’t believe that I could get it to fit until I realised that the black seal around the unit was removable.  Take the seal off, fit this into the new tank aperture and then insert the sender into the seal.  It is a very tight fit.  The sender is secured by a flange plate secured by several bolts (10mm spanner).  I tightened these evenly to ensure a good seal.  Be aware that this plate is below the level of the fuel when the tank is full as the sender is heavily recessed to allow the pickup to reach the bottom of the tank.

TIP: Once the tank is fitted, leave the sender cover off until you fill the tank fully so that you can check for any leaks.  It will be too late once the cover and carpet is back and the boot full of junk.

The old tank is also secured by a metal ‘strap’ which passes over the top and is held on by two bolts (14mm spanner) on each chassis rail.  This must also be removed.  You must also remove the securing bracket on the offside otherwise you can’t get the wing tank in.  So it’s worth doing now.

Tip: This may be the first time (and last time for a while) that you have direct access to the inner side of the chassis rails and the bottom of the boot floor.  I took this opportunity to slap some ‘Kurust’ and underseal on everything I could reach.  It also gives you a chance to nip off for a cup of tea while it dries.

The new tank is just slightly narrower than the gap between the chassis rails.   So by using a trolley jack and my trusty webbing straps it can easily be lifted straight up into position.


Make sure you have fitted the top breather fitting and length of fuel hose onto the top of the tank (14mm spanner for the fitting, 7mm for the jubilee clip).  Route the hose  over the offside chassis rail.

Once in place you can use the supplied nuts and bolts on the front but I had to reuse the existing (captive) bolts at the rear.


It is at this point that (unless you’ve read this of course) you will realise that the anti roll bar will no longer fit.  As you will see in the picture my brackets have been lowered by 50mm to allow for the suspension lift, but even this is not enough.  I will explain later how to solve this..


Now to the wing tank.  Do not underestimate just how much of a ******* of a job this is.  This tank is the specific model which mates with the extended main tank.  If you intend fitting a wing tank only you must get the correct model (I learned this the hard way).


It is an extremely tight fit and you will have to ‘bend’ the bottom of the wing out to get it in.  Tip: it would have been easier to have removed the rear bumper to allow the wing to flex a bit more but it can be done without.

There are 3 threaded holes in the tank (1 balance pipe, 1 main breather, and one additional breather) make sure you fit the main breather fitting (the one with a piece of yellow hose on it) into the hole which aligns with the breather connection ‘spout’ on the new main tank.  All the other fittings can be reached later.


Once again using a trolley jack, 3 house bricks and block of wood the tank can be raised into position.   It will take a bit of wiggling to get in place.


The front of the tank is secured by a removable plate(splash guard) and the rear is secured by two rivnuts drilled into the rear cross member.  I found it easier to leave the tank ‘floating’ on the jack while I fitted the various pipes.  This gave me enough ‘wiggle’ room to make it a bit easier.

The existing main filler pipe(removed earlier) needs to be cut approximately in half (each piece being about 6”).  It is better to measure this up now you have the 2 tanks roughly in the right position relative to each other.  Use the supplied jubilee clips (7mm spanner).  You also need to cut the breather pipe.  You need one piece (about 5”) to join the two tanks and another (about 7”) to attach the wing tank to the end of the breather.   Fitting the breather pipe requires 1″ diameter arms, 14 fingers and Kevlar forearms but it is do-able.  There are no tips I can give here except keep at it, wiggle the tank a lot, have lots of tea breaks and learn to get used to counting to twenty.  I found it easier to fit the pipes between the tanks first.

Once all the hoses are fixed I loosely fitted the front securing plate using the supplied nuts and bolts (14mm spanner).  Then, by jacking up the tank you can see where to drill the cross member for the rivnuts (10mm drill).


You can drill straight through the tank securing holes.  Once drilled, drop the tank slightly.  The 10mm holes will be very tight, I inserted two longer bolts into the rivnuts and tapped (hammered) them into the holes.  The tightness helps hold them still.  Raise the tank again, insert the supplied bolts (14mm spanner) and tighten.


The wing tank does hang down below the wing slightly but is not too obvious.


There is a balance pipe which runs between the bottom of the wing tanks.  On my car it lined up directly to pass through the anti roll bar brackets which will afford it some protection.  Insert the fittings into each tank (14mm spanner) and cut a length of the supplied hose to fit (7mm spanner).


As mentioned earlier the anti roll bar will not fit unless spacers are used.  My brackets were already lowered by 50mm but I needed another 25mm.  I read on a forum somewhere that towbar spacers have the same hole pitch.  So out with the tape measure and off to the local caravan shop and the fact is proven.  Towbar spacers are available in 0.5”, 1” and 1.5” thicknesses and are a perfect fit (they cost about £4 each).


Here is a (bit blurred,sorry) rear view of the finished installation showing how low the tank hangs.


On my car it does not hang below the diff and after a day of off roading the next day I didn’t encounter any problems.  However I don’t think I will be doing any extreme rock crawling with it as it does seem a bit exposed.

It took 2 days for me to complete the job but I had a lot of built-in kit to remove from the boot first.  On top of that I deliberately took my time (to take pictures) and paint everything with underseal.  It is not a job to try and do in a hurry.  Allow yourself plenty of time and make sure you have everything before you start (as you can’t drive to halfords for a bit without a fuel tankEmbarassed ).

So after all that, was it worth it?  I filled the tank with newly filtered vegetable oil and managed to get 160 litres in before I bottled out.  80 litres read half full on the fuel gauge.  One word of caution: the wing tank additional breather pipe is not very long.  This means that it is possible to fill the tank to a point where it can run out of this breather.  I shall be extending mine up the inner wing.

With 160 litres on board, along with my auxiliary 20 litre tank I now have an estimated range of over 1000 miles between fill ups.  At today’s prices it will cost me over £175 to fill Surprised from empty, with diesel,  so I shan’t be doing that too often.

It now means that I don’t need to carry any jerry cans (although I shall probably still take one for transferring) and all the weight is low down.

For an expedition this would seem perfect however there are some drawbacks.  If you carry fuel in jerry cans you can off load them to make the vehicle lighter if you are stuck.  If you suffer contaminated fuel with my tank system, it’s all contaminated rather than just in one can.

So it’s swings and roundabouts which fuel method you choose.

I hope this has been helpful.

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