Fuel Caps leak!

Rubber ring seal inside cap can be bought at parts store>

 

I was given the advice to file the very top lip. The neck will get scratchs and dents when the fuel nozzle is put in the tank. The rubber seal is to rigid to comform and fill the little grooves made by fuel nozzle. I decided not to try this because I don't want the fililngs in my fuel. I just wipe the tank everytime I fuel.

 

Put a rubber O ring in the cap

 

I was just thinking of asking the same question and someone beat me to it. Mine has rubber seals and I actually changed them awhile back with only slight improvement. I wish I would have kept the old ones and put two in each cap. Dont know if that would be too thick though.

 

If you have a groove in the neck, there is a square cut o-ring that goes in it. The problem is that the groove gets beaten up over time and wont hold a the o-ring for very long. The caps also have a flat rubber, so if you could make it flat, it seals OK. I've had some limited success filling the grove in the tank neck with JB Weld and filing it flat. It works until the cap chips away at it again. It would last a while for an O/O who is careful, but it only last a few months for our fleet drivers who slam the caps on. Just stuff a big rag in the hold 1st, so you don't get anything in the fuel.

The only other option I know of is to find a welder than can replace the necks. If anyone has a better solution, I'm all ears, I have 4 trucks with this problem.

 

If you have non lockable spring loaded twist on caps there is a cheap fix that works perfect and you can get it in about any auto parts store.....