solved a little problem

Peter Coomaraswamy

Peter Coomaraswamy

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I thought I would throw this out there, I had allot of trouble finding a sealing gasket for the fuel sending unit that goes in the top of the tank in the trunk. I actually got a BMW part for this but it still leaked and I would occasionally smell gas, especially when I opened the trunk. I found a really good substitute in a spin on oil filter for a V70 Volvo (2004). It's a little thicker but fits perfectly and tightly, though a very thin film of oil will help seat it correctly. So nice not to have that occasional whiff of fuel :-)
 
There are a handful, and then some, places for gas vapors to escape their normal confines.

Here are a few: any hose; where the hose connects to the sender there is supposed to be a plastic sleeve between the hose and nipple on the sender; the evap tank (as mentioned), the gas cap (mit oder ohne luftung), the tank itself and horizontal seam where the two halves are joined; the return hose, if you have one, the short hose between the metal filler to which the cap screws on and the neck of the tank, the vent line under that metal neck under the filler pipe... and so on, more than I can immediately recall.

One way to verify if the tank/sender seal was at fault would be to very nearly fill the tank full of gas, then open the trunk, remove the floorboard over the tank, and rock the car back and forth, looking for wetness around the seal. Otherwise with a full tank, press down on the tank, deflecting it somewhat while looking for wetness.

But if your installation took care of an known leak with certainty, then we're all ears to hear the dimensions of that vovlo seal.

TIA!
 
I will get the dimensions because I tested it thoroughly today and there is no longer any leak at the sender, however, as mentioned below I need to go through every other fitting because the plastic pieces are all missing on my 74. I checked and all the hoses are tight but I still need to triple check. I have the filler neck venting outside the car through a hole next to the tank with a grommet so it should be tight. I have the fume bottle (grey plastic) disconnected and the top tank vent plugged. I also run an electric fuel pump back there but everything looks dry, so it could be my imagination but I'm still smelling a little fuel. I'll keep checking, but the oil filter gasket is really doing its job.
 
After you go through all that's in the trunk, there should be no smell of fuel - from the trunk.

However, up front there's another whole bowl of worms. Start with the crankcase breather, is it still adequately connected to the bottom of the air filter?

Do your carbs leak at allllll, or is there possibly a slight fuel leak in the engine compartment anywhere? It only takes a little bit of gas, just a small drip, and you'll smell it in the seats. How: must make sure the three gutter drains from the winshield wiper area are intact, because smell that gets into the gutter area will enter the compartment through the vents.

The transverse gasket at the forward/top of the gutter, plus the pieces on either side, have to be present and functional. Again if they are leaking, engine compartment smell will come in.

Unlikely, but mentionable... are all the penetrations in the firewall correctly sealed, including for AC hoses, pedals and steering column?

A doctoral thesis could be written on correcting all this, but I won't be the one.

Hope this helps.
 
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