Leaky gas cap

[OrangeJuice]

Hi everyone,

This has been a problem since I bought my truck. The aft gas cap seems to spill a little fuel from the cap after filling up. The cap is a vented locking cap and I'm thinking the gas is leaking through the vented hole on the back side and not so much around the rubber seal. I'm having to clean the real quarter panel quite often. I try not to top off this tank as it seems to help a bit. Has anyone else experienced this problem with their caps and is there a fix to the problem.

Thank You

[81-F-150-Explorer]

Have you tried buying a new gas cap?

[OrangeJuice]

yes, I have replaced it several times with the same results.

[Ds7776]

Ive had this problem on my 70 F100 with an in cab gass tank its the gas vapors expanding and pushing gas up into the fill hose. Ive had no success in fixing my leak but it seems to help when I park it so that the driver side sits up higher. O reven parking in the shade and not filling up right before parking.

[81-F-150-Explorer]

Originally Posted by OrangeJuice

yes, I have replaced it several times with the same results.

Have you tried putting a non-locking cap on the truck. Locking caps are notorious for leaking through the seal.

Also if your truck is equipped with an evaporation system, check to see if the hoses going to the charcoal canister is in good shape, and also check the vent on top of the tank. Make sure there are no blockages.

Also, it is a good idea, especially with trucks with evaporative systems, not to top off the gas tank. Fill it to the first shutoff only to prevent gas from entering the evap system and blocking it. In California it is ilegal to top off a gas tank for this reason.

Good luck.

[czaroc]

Can you even fill a pre '77 in Calif? I have to drive around to find the "old" style pumps to fill mine. I can't get the new style nozzles to work.

[81-F-150-Explorer]

Originally Posted by czaroc

Can you even fill a pre '77 in Calif? I have to drive around to find the "old" style pumps to fill mine. I can't get the new style nozzles to work.

Yes but it's a pain in the you know where. The evaporation recovery on the gas station nozzle seals too well.

It's the same when you try and fill a gas can. Cant vent the air fast enough.


The best success I've had with my 1973, is to turn the gas nozzle upside down from normal. This keeps the nozzle from sealing 100% on the truck.

good luck.

[OrangeJuice]

Thanks for the help everyone. This leaking problem has never happened with the front gas cap, always the rear. Not sure why. Maybe the design/angle of the front filler tube?....I don't know. I've even seen the fuel spewing out of the rear cap area after filling-up and making a right turn...Yikes! I have not tried a nonlocking gas cap especially now with the high cost of fuel. I guess I could try it, but I'm worried someone would have a field-day with the amout of fuel our trucks hold.

Thanks again everyone.

[Shamus]

It truly sounds like that tanks vents are blocked.

[OrangeJuice]

They may be. I'll have to check that.

Thanks

[Ds7776]

It spews out when you turn could you tank supports straps or brackets be broke or hang lower on one side?