Long range GU sub tank install

[AJD3671]

Hi All,

Hoping for a little guidance on removing the sug tank in my 09GU wagon. Install instructions from Brown Davis say to remove the filler cover from rear wheel arch and then disconnect filler, breather etc... The problem I see is that even once disconnected wher the instructions indicate it is still connected further along including on the metal pipe section of the filler bolted to the chassis rail. I have removed these two bolts also but there is not enough movement to sugest that the its going to come out.

Any ideas?

[mudski]

I think that pipe you speak of is actually from the front of the tank at the pump and heads to the main tank. Been a while when I did mine...

[AJD3671]

No there is a seperate pipe to the main. This one has two lower brackets bolted to the chassis with another rubber section of hose that goes to the sub tank. There is another clamp but it can't be accessed.

[MudRunnerTD]

Can you post a pic of the instructions and the pipe.

[AJD3671]

So for anyone looking at fitting the Brown Davis 80 LR sub tank to diesel GU wagon take their garbage instructions cut in half, hole punch them and tie them with a bit of string to a toilet roll holder in a public toilet.... More seriously though they say to remove the filler neck and disconnect the fill and breather hoses. I did this and for the life of me could not work out why. I then proceeded to unbolt the fixed section of pipe bolted to the chassis rail to try to get enough flex where they connect to the tank. Again a waste of time and effort as neither of these made any difference until bolting it back together and it was bloody hard to get the pipe lined up to the original mounting bolt holes in the chassis rail. My step by step recommendations and by no means should these be considered perfect are as follows.

1/ Drain or pump out factory sub to main. I found there was still about 5L left after pump cut out.
2/ Get the vehicle safely to a suitable working height and support on stands. I only raised rear but would probably have been easier to raise all four corners if I'd been able to.
3/ Remove sub tank pump guard to allow easier access to front mount bolts and wiring
4/ Disconnect wiring harness at pump
5/ Disconnect wiring harness at rear of tank
6/ Remove front tank mounting bolts 17mm which are top down and tank will be supported on cross member.
7/ Support tank just rear of centre and remove rear mounting bolts again 17mm.
8/ With assistance working the jack push rear of tank as far forward as possible to clear and lower past trailing arm mount. Mine fowled and required a little assistance from a pry bar but not much.
9/ Once clear of trailing arm mount start to move the tank rearward again to allow front mount to clear cross member and come down.
10/ Lower tank far enough to be able to access the main filler hose and fast fill breather and after securing tank disconnect both. You don't have much margin/slack here so take it easy. A torch and inspection mirror make this a lot easier but it required a lot of twisting and wriggling hence the call for another jack or car stand to help keep the tank balanced.
11/ Disconnect wiring connector on top of float along with sub tank pump lines and as above minmal room and slack take your time and use an inspection mirror.
12/ lower tank and remove from under vehicle double checking that everything has been disconnected.
13/ Ensure that the transfer and breather hoses are both swapped for the longer ones included in the kit. This instruction was not included and I missed it taking an additional hour to gut the interior and access from under rear passenger seat.
14/ Assuming the tank is set up with the fittings, the float extension has been completed, the float refitted and the tank has been flushed move the new tank under car ready to lift into place. Don’t underestimate how important flushing the tank is. We did it 3 times and the amount of swarf that came out staggered me and we also found a plastic bung that had somehow made its way in there. Not sure what Brown Davis dispatch inspection entails but suspect it's a tick and flick exercise
15/ Again with assistance start to raise the tank into place while reconnecting the float wiring, main fill line, fast fill breather and sub tank pump lines. If you cannot get your hands up and over to do this as there is very limited room you may find it easier to lift the rear seats carpet etc… and go in through the access cover in under the back seat. This is painful particularly if you have a cargo barrier, draws or a fridge slide as we found having missed fitting the new hoses in the first place.
16/ Working in reverse order slide front of tank up over front cross member before lifting rear of tank and installing rear bolts first. It may be worth while running a tap up through the thread and ensuring the bolts are well cleaned of Loctite while there is no tank in place to prevent in cross threading when refitted. Trust me it is near impossible to run a tap once the new tank is in place.
17/ Install front bolts loosely and get tank into final position before tightening all bolts completely.
18/ Get the car back on the ground fill and check for leaks, pump operation etc…

I found that the new tank was easier to get into place than the factory tank had been to remove. The capacity gain from a usable 27L is about 48L and in an emergency the position of the rear drain would easily allow me to drop the last 5L into a jerry can and T/F to the main. All up at 170Lplus on board I’m pretty happy. I’m not sure how this would apply to other manufactures tanks or to a petrol GU but it may assist. Unfortunately I did not think to take photos as I went but if anyone has questions feel free to ask me.

[AJD3671]

Oh and disconnect your battery to prevent running the pump dry.