Leaky gas cap

[tonymus]

I recently bought a 2 owner '72 shortbed. The 2nd owner replaced the gas tank and repainted it the original color 6 years ago. It's a 350/350 with a posi rear. I love driving it with one exception- while driving, gas will spill out of the filler when the tank is full to half full. I took off the cap that came with the truck as it wasn't an original. I tried an original with no luck and even tried shimming the gasket with another thin gasket. That helped some, but not enough. Anyone else have issues with repo tanks and filler tubes? I've owned a few 67-72 trucks and never had this come up.

[RexDodge]

Is the tank vented properly? If not that could contribute to the problem. How much fall do you have from the filler to the tank? And you know someone is going to ask for pictures

[tonymus]

I will check the vent. The tank is a repo behind the seat tank so I'm guessing the fall is ok.
Thanks.

[1972RedNeck]

Originally Posted by RexDodge

And you know someone is going to ask for pictures

I wasn't going to, but

[jchav62]

My '67 did the same thing. A new gas cap fixed the problem.

[tonymus]

I'm going to Spring Carlisle so I will shop around for a new one then. Thanks.

[twouvakind]

My filler neck has a ding in it from a gas nozzle, it does the same thing. Look carefully at the neck itself. I may try to epoxy it smooth or otherwise fill it.

[dan42]

My '67 did that as well. I replaced the cap with a GM original cap from Classic Industries (wasn't cheap - around 35 bucks) and no problems now. I believe the rim on the tank itself can actually wear and cause leaking too. Unfortunately the repo tanks aren't much better from what I have heard.

[68gmsee]

Sadly, most of these trucks will eventually wind up leaking in this area either through wear, overfilling, defective gas caps and/or from crappy aftermarket tanks. Mine used to leak if I over filled it and/or when parked on an incline with too much gas in the tank. A good cap will help and maybe even a new fuel tank (I bought a Spectra and highly recommend that brand).

But, first thing I'd try is a good, new vented cap as mentioned above and then not fill it past the first click on the pump -maybe even shut the pump off before it reaches the neck area.

[twouvakind]

Try to reduce the right turns you make. Seriously, maybe keep the fuel at 1/2 a tank.

[Lippyp]

Mine also did this when I got it and as the rubber grommet around the filler neck was perished it ran into the cab and stunk me out. A new grommet and new cap sorted it though.

[tonymus]

Thanks to all who gave their ideas. I just picked up a repo cap from a Chevy Truck dealer at Spring Carlisle. I will try it early this week.