RichieRoo

Ok... this weeks problem is a fuel leak.

I noticed the smell of petrol as I queued in traffic and when I parked the car
and peered underneath, the fuel was dripping out from beneath the tank at
quite a rate.

By the time I got home (fire extinguisher on my lap all the way) it had lost
1/4 of a tank and it stank.

The leak appears to be the short rubber pipe from the fuel pump.
If you take a close look at the photo you can just make out the hose
has worn down to the braiding.

Any helpful advice on draining the tank, depressurizing the system,
not spontaneously combusting, part numbers etc would be appreciated.

hacked off

newsboy

You need to get to the fuel pump. Before you do anything, pull the DME (fuel pump relay). Get the car up on some jackstands. There is a cover which is held on by 5 or 6 bolts that you have to remove first. After that, remove the 3 hex bolts that hold the fuel pump in place. if your lucky, the banjo fitting may have become loose. You can re-tighten it (the big banjo nut), but it's easier if you pull the pump down(hoses still attached) do do it. I recently had this happen and I decided to pull the inlet hose & drain the gas, as opposed to having the gas drip all over me. There are washers on either side of the banjo fitting, and they should re-seal when tightened. Hopefully, the leak is not in the fuel line to the engine. The pump s encased in a 2 piece rubber enclosure, but it's really not necessary to open it, unless you need to replace the pump.

newsboy

One other thing. It's hard to tell from your picture, where the leak is coming from. It could be the supply hose from the tank to the pump. Loosen the gas cap. If you drain, first clamp the line with a vise grip to slow the flow(ask me how I know), then pull the hose to drain.

RichieRoo

cheers newsboy. I don't suppose you can make it out in the picture, but the cover you refer to is off and the bolt holding the fuel pump are out. Fuel pump is dangling in the foreground.

Thanks for your comments... good to know I'm on the right lines. I'll do as you mention and drain the tank next.

RichieRoo

Do you know if it's possible to detach the brass hose fitting and just replace the rubber hose. Or do you have to buy the hose and fitting?

Indycam

IIRC its an all or nothing sort of deal .

RichieRoo

Thanks Indycam... just took my old pipe into Porsche and ordered a new one.

I removed the fuel tank for a better inspection only to find that not only was
the pipe worn through, but it looks like the connection to the tank has been
bodged as well (see photos). The return fuel pipe appeared to have been
sealed with silicon sealant and the long perforated tube simply slid out out
the fuel tank.

Can anyone describe the fuel tank return fitting should look... I'm guessing that
the perforated tube should be bonded into a threaded plastic plug, which
screws into the hole in the bottom of the tank... is that correct?

Wachuko

Only photo I have... removed tank when I was working with the evaporator...

Wachuko

Looks like they did a nasty patch work on that return line...

RichieRoo

Ah thanks Jamie. That helps.

Yep, that looks the same as mine... 20 gallons of fuel held back by a friction
fit tube which you can slide out with your fingers... marvellous!

I feel a modification coming on.

RichieRoo

This was the solution which I went with in the end:

I fabricated an oversize, aluminum, fuel return tube to replace the original
Porsche one. Welded a thick aluminum shoulder onto it to provide lateral
stability and as an anchor for the resin.

I bonded a short collar of pvc tubing onto the tank using Solvent Weld
and flowed glass fibre resin around the outside edge.

Drilled out the original 10mm hole to a very, very tight fitting 12mm.
The 12mm fuel return pipe was then forced into it creating a watertight seal.
To prevent the pipe moving and act as a secondary seal, I poured resin into
the collar, encasing the aluminum pipe and shoulder.

Once set, I sprayed it matt black to match the tank and fitted the new
Porsche hose. Indycam was right, the brass fittings are bonded on so you
need the whole thing. I also replaced the suction hose from the fuel pump
as a precaution.

I put two litres of fuel into the tank, ran the car and then left it overnight
to check for leaks...

So far, so good.

Thanks for everyones input.

demonfish

impressive work...

Wachuko

Outstanding!!!

demonfish

that said Jaime, that new pipe looks a little wonky...

Wachuko

In the before pouring resin photo they both look aligned. I wonder if it is a photo angle issue or it actually moved while the resin was drying... either way, sure beats having to buy a new gas tank