Fuel tank breathers - 1972 car

[RobStan]

I'm sure I'm not the only one, but my car smells of petrol. It's fine when it's running but when you come back to it it smells strongly of petrol.

So I'm just going over the tank and replacing the old pipes and I have a question.
There is a breather pipe on the top of the tank, and another on the underside of the filler cap. These 2 points are connected and in the middle there is a 'T' with another pipe leading out of the car via a small hole in the rear skirt.

Is this all correct? I can't help feel that this other pipe from the T shouldn't be there, and also if I fill the tank surely it'll leak fuel...

Cheers
Rob

[Adrian@]

The T piece is standard.....Try this, add a second J clip to the 2" filler neck of the tank (the opposite way round to the other one and as high as possible) to stop you from putting petrol between the neck and the pipe when , sitting there and draining down into the cabin. Adrian@

[RobStan]

Cheers Adrian, I'd taken your advice on this previously and already added the extra click.

I can't see any sign of leaking which is why I thought, maybe wrongly, it was a vapour problem and therefore related to the breather pipes.

[pumpkin]

It is different on my 78 car.
There are two small pipes brazed to the filler neck. The highest is connected to the overflow/vent that sticks out of the bottom of the car. I had to put a plug with a pinhole in this to stop petrol pouring out on bends during track days and entertaining bored marshals.
The other connects down to the tank and vents the top of the tank into the filler neck. Because the diameter is too small, filling the tank is very slow once the level is high enough in the tank to need this vent (At least the final third of the tank). There is no "T" in this line on my car.
I can't see why your car would not pour out petrol when the petrol level is above the "T" due to filling or cornering

[RobStan]

This is my problem. If I try to put more than half a tank of juice in I start leaving it behind on the forecourt and corners.

I wonder if I can loop the breather pipe off the T in a high U bend so the top of the loop is as high as possible above the tank, the pressure could be released if needed put keep the pettrol in??

Any thoughts?

[threespins]

That's what Adrian advised me to do, running it as long as you can over the near side wheel arch. Worked for me.

[Adrian@]

There you go.....that's the next thing to do.
Adrian@

[RobStan]

Cheers Guys