Small amount of gas on top of tank

[Nelson and Hudson]

Hello, I noticed a small amount of gas that accumulates on the top of my gas tank near the tubing. After a quick drive >2mi I noticed fresh fluid (a little more than a few drops, no puddles). Should I be concerned? Does this affect my fuel economy?

 

[alwaysFlOoReD]

I would be a bit concerned. Not too likely that sparks will happen but stranger thing have happened. The rubber line with the hose clamp, inspect it closely. If there is enough, cut it back so the clamp is on new hose.

 

[RonD]

Yes it will for sure effect MPG

If tank wasn't full then the leak is in one of the hose connections
The hose with the 90deg fitting is the 35psi pressure hose so most likely to leak

The other hose with the clamp is 0psi but does have "flow", its the return line from the Fuel Pressure regulator on the engine, so can also leak if pipe or hose is cracked

If you dry off the gas then let the engine idle for a few minutes and see more gas then its a hose

If you only see more gas after driving it around then the gasket on the hold down ring is leaking, gas in the tank is sloshing around and splashing out

 

[lil_Blue_Ford]

I’ve also seen rubber hose “pinhole” and leak, seems to be most common to happen to either non fuel rated line or regular fuel line. The “high pressure” rubber fuel line doesn’t seem to experience this problem and I suspect that it has something to do with ethanol gas. My 92 had a section of rubber line on it that was leaking pretty good. I thought it got cut somewhere that I couldn’t get a good look at and when I fished it out, I was surprised to find it looked fine, but a close inspection showed pinholes all through it. Not sure if I saved any, should have taken a picture.

I‘ve also seen a leak at the hold down ring, so definitely something worth investigating

 

[Cees Klumper]

Besides the fire danger your Bronco may not pass CA smog next time if you have an EVAP leak ...

 

[Nelson and Hudson]

If you dry off the gas then let the engine idle for a few minutes and see more gas then its a hose

If you only see more gas after driving it around then the gasket on the hold down ring is leaking, gas in the tank is sloshing around and splashing out

Now that's clever problem solving, thank you!

 

[Nelson and Hudson]

Besides the fire danger your Bronco may not pass CA smog next time if you have an EVAP leak ...

Funny you should mention that, I live in CA and barely passed

 

[JerryC]

If it is the gasket leaking, when you replace the gasket make sure to buy a new lock ring. The lock ring loses it's ability to put tension on the gasket and will work loose. I learned this one the hard way.

It is recommended to use a brass punch on the lock ring so it won't make a spark

 

[Uncle Gump]

It's rare that @RonD gets it wrong. That said... that factory 90 degree fitting is the return line with no pressure. The rubber hose and hose clamp is the pressure side of the sending unit. If your truck has the two pump system (which it probably does) its the low pressure pump supply hose to the frame mounted fuel reservoir. In which case the hose and clamp is probably adequate but certainly isn't a proper fix of the factory lines.

Here is a picture of my sending unit with a high pressure pump mod fir reference.

To me... it sure looks like the sending unit seal is leaking on yours.