Dont do this!

[Lone Ranger]

I was going through some older photos on my phone and found this one a few years back. This is my 72 f100 4x4 (sold now). I filled the truck up with fuel and drove it straight home. I must have parked on a slight incline and came out a few hours later to find this.

I was able to sand it all down and repainted it but it made sick to find it like this. My old man said when he was younger he did it to an almost brand new 76 highboy. Don't overfill your tank and park on an incline on a hot day! I've seen many pictures of these trucks with no paint under the tank fill. Anybody else ever done this?

[Ranchero50]

Diesel doesn't do it.

[Lone Ranger]

This is true. I would love to have a cummins in mine. You want to put one in my truck?

[1972hiboy]

oh man that would have made me sick to my stomach too...........

[69Ford]

Been there done that. Its a sad feeling.

[59yblockf100]

been there too,this happens alot,

[jimmy828]

I wonder if that will happen with the modern day paints such as urethanes

[Lone Ranger]

This was a modern paint. I had only painted it a few months prior to this picture. It was just a mid grade paint from my napa store. Can't remember what kind it was tho.

[MadJoe]

I was going through some older photos on my phone and found this one a few years back. This is my 72 f100 4x4 (sold now). I filled the truck up with fuel and drove it straight home. I must have parked on a slight incline and came out a few hours later to find this.

I was able to sand it all down and repainted it but it made sick to find it like this. My old man said when he was younger he did it to an almost brand new 76 highboy. Don't overfill your tank and park on an incline on a hot day! I've seen many pictures of these trucks with no paint under the tank fill. Anybody else ever done this?

That's funny, a couple weeks ago I did exactly that. My entire road is on a slant, and the way I park the truck normally the driver's side is on the lower side. I filled it up one day and parked it as usual not really thinking about it. Well, it was unseasonably warm the next day, so when I came out it was to an active fuel stream gushing down the side of my truck. I just turned it around and cleaned up what I could, and then vowed to never fill it up to the top again because I know I'll forget. I chalked it up to a worn out cap, so I got a locking one. That one was even loser, so I cut a gasket out of chemical-resistant rubber I had laying around and bolstered it. Now I get a suction noise every time I open the cap.

[69Ford]

There are two types of cap's vented and unvented. If you use the unvented cap on a unvented fuel system it will create a vacuum in your fuel tank causing your engine to strive for fuel as it is fighting for fuel against the vacuum. This can be very hard to diagnose. Sometimes with a full tank that was filled with cold gas on a hot day can cause a pressurized condition in the tank forcing gas out of a vented cap. Especially if that cap already has fuel against it. As parking the truck on a slant drivers side lower. I'm not a 100% sure but think the early bumps had an unvented fuel system requiring a vented cap later bumps have a vented fuel system no need for vented cap.

[PetesPonies]

The paint was the problem. I'm betting it was acrylic enamel and without hardener used, right?

[Lone Ranger]

The paint was the problem. I'm betting it was acrylic enamel and without hardener used, right?

I don't remember what type of paint I used. It was a mid grade automotive from Napa. Had hardener in it but no clear coat.

[MadJoe]

There are two types of cap's vented and unvented. If you use the unvented cap on a unvented fuel system it will create a vacuum in your fuel tank causing your engine to strive for fuel as it is fighting for fuel against the vacuum. This can be very hard to diagnose. Sometimes with a full tank that was filled with cold gas on a hot day can cause a pressurized condition in the tank forcing gas out of a vented cap. Especially if that cap already has fuel against it. As parking the truck on a slant drivers side lower. I'm not a 100% sure but think the early bumps had an unvented fuel system requiring a vented cap later bumps have a vented fuel system no need for vented cap.

I am fairly certain the '71's and newer had the venting system, but I can't be absolutely certain. I really need to look and see if my tank has it or not, I've just been being lazy. But, because I'm not sure, I have been pretty good about popping the cap off every time I open the door to get in the truck to normalize the pressure in the tank "just in case". I don't typically drive it long distances, either. Today was a rare exception where I went 30 miles to work because I have an appointment to get a quote on rebuilding the engine after work and they wanted to see it (I think they might think the engine is already out of the truck, so this could be interesting).

And now the paint under my cap is a big mess. Apparently the PO was aware of this potential issue and never allowed it to happen because the truck hasn't been painted since the '80's and that area was fine prior to my screw up.

[PetesPonies]

Acrylic enamel gets reduced with an acrylic reducer, but doe snot need hardener. Many times it is sprayed with hardener which makes it more durable, but it will cure without it.