Leaking petrol tank

[Shaguar]

My early season problems continue, filled up with petrol the other day, on returning home and garaging her there was a strong smell of petrol in the garage. As we have an attached garage it lingered into the house also :x On investigation petrol was leaking from the bottom of the car under the fuel tank area. Removed the tank sealing plate on the top of the tank and the fuel was over the joint of two halves of the tank. Siphoned out some petrol until it was below the joint and it appeared to stop leaking. Is this a common problem My plan is to siphon out the rest and then remove the tank. There also appears to be a filter attachment nut on the end of the outlet pipe but no filter

On a positive note, whilst filling up an old lady approached me and said, "that's a beautiful pussy cat". Makes it all worth the while doesn't it :D

[christopher storey]

A leak from the joint between top and bottom halves of the tank seems unusual to me. There are 3 common sources of leaks/strong petrol smells in my experience .

1. First, and most common, is that one of the top gaskets is leaking ( either the large plate for fuel delivery, or the fuel gauge sender plate). Apparently a trap for the unwary here is that the BA bolts securing the plates can bottom in the bolt holes in replacement tanks, and thus not torque down the plate onto the gasket as designed. Leakage from this source usually betrays itself as a brownish stain on the tank top, and obviously, the fuller the tank, the greater the potential for this type of leak

2. The gasket on the brass sump ( the circular bit which sticks out through the bottom of the boot floor ) has either failed or is missing! There should be a cork/fibre gasket between the two

3. I have kept the nastiest until last : because all fuel contains water, and in winter condensation affects the interior of tanks , the tanks over 40 years can rot at the bottom , usually where the flanges of the internal baffles are spot welded to the bottom of the tank . The metal becomes paper thin and gets pinholed . This is either a case for a new tank ( about ?400 ) or sometimes you can get away with a repair. UNDER NO CIRCUMSTANCES TRY TO GRIND/CUT THE TANK , NOR APPLY HEAT IN THE SHAPE OF WELD/BRAZE/SOLDERING UNTIL THE TANK HAS BEEN STEAMED OUT THOROUGHLY FOR 3 OR 4 HOURS. DON'T LET ANYONE TELL YOU THIS IS NOT NECCESSARY AS THE CONSEQUENCES USUALLY ARE FATAL . Sometimes you can then weld in a patch and treat the tank with an aviation type sealant

The leaks of this type are sometimes intermittent , as yours seems to be , because they depend on hydrostatic pressure exerted by the fuel i.e. the deeper the fuel the greater the leak potential through pinholes

A fourth thing I would check , although it's not common, is that there is not a leak from the filler hose or the drain hose which should drain the filler cap area out through the bottom of the left hand rear wing

Good luck!

[Shaguar]

I've got the tank out and there appears to be no holes or signs of leaks and I'm suspecting number 2 on your list (the sump gasket). With the tank out of the car can I replace the gasket and water test it