fuel tank leak

[harry3]

my 6cyl fuel tank is leaking apaarently thru the weld where the return pipe is welded to the bottom of the tank

I have a spare parts car so it seems the easiest way is to swap over the tank, is this straight forward?
the tank would have to come off for any pernmanent repairs I expect??

[VL Berlina 5speed]

it would have to come out but repairs, is very dangerous as metal absorbes petrol particals into the metal structure and when you go to weld it it will be the last job you do on your car, best bet would be swap safer easyer and if u were repairing it you are half way there to swaping it

[Sabbath']

Swapping is quite simple.

What needs to be done (from memory)

Make sure the tank is empty, or, if not only a minimal amount left in there

-Remove all fuel lines to the tank

-Remove all electricals from the tank

-If you have a towbar (heavy duty me thinks) that bolts up near the diff and at the very back, right underneath the plates, there are 4 bolts underneath the back bumper so it has to come off before the towbar will come out

-Undo/Loosen the bolts which hold the straps on

- Get some vaseline and rub it on the filler neck just inside the petrol cap recess. (this will help to pull it through the rubber)

- Fully undo the bolts on the straps and pull like buggery on the tank to get it out.


Refitting is the reverse

Dont know if there is a better way but it worked for me.

Shouldnt take too long


While i had it out i also painted the tank and straps and towbar

[harry3]

thanks, thats what I will have to do, luckily there is no towbar

[prince_dj666]

i have a leak too in my vlt. it leaks on the top weld just under where u fill the tank. i was chasing a drop tank for it....

[seveprim]

arh I once had a leak in the tank it is actualy a trick to it all .. do not weld, but instead silver solder it ..... how you ask....

Tools needed
1. Butane gas blower (about 7 bucks from Dick Smith aka DSE) pencil touch blue catlouge no t1380
2. Butane (DSE)(about 7 bucks)
3.Bunnings (tool department) Kester acid flux paste($30)
4.Bunnings (silver solder) read and get the one for plumber (2% silver)($20)
5.One steel brush and some sand paper
6.Kill rust paint and normal paint
7.4 litre of metholated spirits

How to fix!!!
1.Simple remove said tank (plus any excess fuel and pump/electronics sender)

2. YOU MUST DO THIS STEP !!!!!! FILL TANK WITH WATER !!!!! This is the reason you can do it safely water replaces air without air no fire!!! DO this 3 times before proceeding !!!! EMPTY TANK and move AWAY FROM SLUDGE

3.REFILL TANK(with water) AGAIN IN NEW LOCATION FROM SLUDGE


4.Find hole(s) Clean with sand paper and steel brush (make it shinny even if you must remove more !!!!

5.Apply acid flux in around hole (while tank is still full of water)
Note depending on location you may need to jury rig a plug to stop water escaping !!!

6.Apply ample heat to said hole location and add solder until hole(s) are filled and are fairly smooth.

7. Apply water pressure to the tank via hose and check solder is holding pressure (look for droplets forming from the repaired holes check very carefully for other possible holes too !!!

8. Drain water (if sealed ok ) otherwise retrace steps until seal test ok

9. Remove excess flux and clean area again with sand paper and brush

10. Apply many coates of kill rust paint and top coat of paint of your choice

11. Allow a day in the sun to aid in water removal

12. refit tank+electronics and pump

13. Place 4 liters of metholated spirits in tank and FILL TANK with petrol

The metho forms with the remaining water in tank and allows it to burn safely in engine ..

I did this repair on my VN tank in 2001 and all is fine and has not leak since !!!

Good luck should cost not much more then 50 -60 and a few days (weekend)

[VL Berlina 5speed]

a butane tourch is a bit cutting it close to danger, the reason it is not recomended welding is bcause the tank absorbs little petrol particals into the metal and stores them with the structure, thats why its no reckomneded to weld or crush cars with petrol tanks.

and dont say crushing or weld will cause it to happen to you, a family friend in England was kill years back when he was crushing a semi trailer that was a fuel tanker, was stored for years at this wreakers and then when he crusied it the fuel in the metal compressed to a limit then exploded killing him, so its has happened and could

[Sabbath']

In my opinion its better to be safe than sorry. Just buy a new tank from the wreckers. I mean, if you have to take the tank out to do this, might aswell just whack another one in, cant be too expensive, never priced one up though. Saves the risk of mucking up and hurting or killing yourself

[harry3]

thanks for the advice but since I have a parts car I will swap its fuel tank over, am half way thru the job, got the old tank out fairly easily
my tank seems to have been soldered before where its leaking, suggesting the repair didnt last. the leak is near where a pipe is attached for the fuel return line, which I think, takes the fuel into the swirl pot, which the filter bag of the internal pump is supposed to sit in

re filling the tank with water, I imagine the internal electric pump would need to be removed and the cover part replaced before doing this
but some books say the sedans dont have the internal pump??

I know that an empty fuel container is often more dangerous than a full one due to heat creating a fuel vapour from scregs fuel remaining

finally a frequent cause of garage fires is work on the fuel system without putting out the gas hot water heater pilot light, which can ignite any fuel vapour floating around in the garage

[vk3800]

Just for those that may want to repare their tanks instead of replacing it.
A much safer way to repare the hole is by use a product call JB Weld. It's a two part epoxy that is applied cold. Just clean the area around the hole and apply over holes.
I used it on my tank where it had pin holes in it, Three years later and no leaks.

However, wouldn't recommend repairing the pipe into the tank for the return fuel line as i had nothing but problems after i repaired it. Not from leaking, as the JB Weld held, but from removing the pipe totally to claen the area.

So if you just got so pin holes, use the JB Weld. If it the return line, get another tank.

prince_dj666 - are you sure the weld is broken, it could be one of the breather lines that run across the top of the tank.

[vlv8vic]

sure its the metal leaking? its very common for the hoses around the filler/overflow to fall to bits and leak on VLs. ive replaced mine.

[Holdfast]

I reckon that stuff called "Selleys Knead it" is ripper stuff

It's a epoxy putty that is really easy to use and lasts a really long time; I carry it in my tool kit in the car and the boat.

Check it out

[Sabbath']

sure its the metal leaking? its very common for the hoses around the filler/overflow to fall to bits and leak on VLs. ive replaced mine.

I found that too with mine, before i had the tank out, i noticed a drop of petrol on the drive and went to investigate, put my hand under the gaurd and the hose pretty much crumbled to dust in my fingertips

So i did a quick repair job, and when i say "quick" i mean i didnt take the tank out, just went to the best piece of hose remaining, cut and then put a plastic through connector in to a brand new piece of hose, then when i had the tank out i replaced the lot again followed by the fuel pump.

No more leaks

[harry3]

Ive now got the parts car tank out and there is a collection of clear plastic tubing in very poor condition near the filler pipe that would have been for fuel evaporation control, and originally under the mudguard
this I think would be a cause of petrol smells, the tubing is transparent and seems to have been the wrong type, not able to cope with petrol vapor