Fuel tank vent?

From day one with my van, i've had a fuel smell at the tank. It had a large dent and small hole in the bottom. I had the tank fixed months ago and last weekend i replaced the vent? hose from the top/side of the tank to the fill pipe. The smell was almost gone and i found the cheap locking gas cap was not sealing very well. I went to napa and picked up a 703-1221 cap. I filled it up and the smell was gone, all good until this morning. I found a puddle under the tank from the sending unit not sealing to the tank. I removed the cap and the tank had ALOT of pressure in it.

What am i missing here?? Do i need to add a vent or different cap? Or is the pressure fine and i just need to re-seal the sending unit.

thanks

john

The cap has a spring loaded vent, but it must take alot to open it. I took some wire to stick open the vent and it seems to do the trick. At least this way it won't build up pressure and it's sealed from rain.

I just wanted to make sure i wasn't missing something.

I guess i could put a fitting in the filler neck (up high) and install a used charcoal canister from another car.

john

May want to make sure the vent line isn't blocked. Mine was kinked as it made it's upward bend.

I was just thinking these things have to be an open vent and not spring loaded ,, that would be for rollover protection wouldn't it?

The vans been in the garage all weekend. It's building the pressure just sitting there. The vent is a straight shot from the tank to fill pipe and it's 1/2 inch hose.

I'll go find a charcoal canister and add a vent to it. All that (any) pressure can't be good for a 45 year old already fixed tank!! LOL

It could very well be a rollover valve. Your picture looks like what i have and by that, how would it vent unless it uses the cap. Unless somewhere else on the tank, that i don't see.

yep, thats all there is ,, the chevys are the same way for the most of them, gas cap does little more than keep the dirt and water out.

LOL

thanks guys

Pull the gas pipe- check the vent/ overflow hose=pipe- with Compressed air - remember - you may have a vented type gas cap that isnt venting good - drill a small hole thru gasket & cap into area just under the top - it will ven good then.or u can drill a small hole in top area on gas pipe also just under the cap sealing arae - doesnt take a hole larger that a .030 dia .