Bill - THANKS!!

This is next on my list of mods. As in your write up, I researched and bookmarked all the previous posts, links, etc. over the past week in preparation to do the mod next weekend. I was very disappointed I could not find any pictures. Your post and your writeup is AWESOME and came just at the right time for me. I assume since you have the FX4 that you had all the skid plates and they were no problem??

I'll try to double rep you - this was an excellent post!

 

Yes, I have the skid plate and I did not have to touch it. It only covers the bottom so it does not interfere.


Thanks for the kind words,
Bill

 

Perfect write-up for a one man show!
I'll just add "IF" you have a couple buddies the bed can be completely removed
by removing those last two bolts and unpluging the tail lights.Then you get unlimited access to the tank while standing straight up. I would guess the bed's weight at around 250 lbs but it's length makes the long bed hard to balance.
2 men could probably do it,3 men can handle the bed with ease, 4 men would be a finger snap.

 

My truck was in the body shop and the bed was off. So I headed over with some tools to do this simple mod.

I marked the ring and plate with a scratch awl.

I use a 3lb sledge and a dull screwdriver to get the ring off.

I had to reach in all the way up to my elbow to clip the two tubes.

The tubes do not float, and I didn't want them to be swimming around in there, so I had to fish them out off of the bottom of the tank (so much for rubber gloves)

Re-threading the ring correctly was the hardest part of the whole thing.

Start to finish, less than 10 minutes.

 

With the bed off can you get to the vent hoses under the cab? When I fill up my tank I get diesel leaking right at the first shutoff. It is leaking from the front of the tank on top. I don't have any jack stands or 2 ton jacks but I do have a couple of neighbors that can help me lift the bed (short box). I figured I will harpoon the tank while I'm at it.

 

You shouldn't have a [problem. The vent and fill tubes are at th rear of the tank, there is a cross over vent tube over the top of the tank which might be loss hence the leak showing at the front of the tank.

There is plenty of room to reach inside the tank, towards the rear of the truck, to clip off the 4" or so that you need to trim. Get a PVC clipper at a hardware store to easiley do the job. They will fall to the bottom of the tank so having as little fuel in the tank as possible helps out here.

Good luck!

 

Yes, you can get to it all if you pull the bed. And you will probably be able to see where it's leaking as well. I don't think it's the tank vents, because they are above the fill point and don't see anything but air when you fill up. I'm betting it's the fill tube or the fill vent tube. They just have hose clamps holding them on.

 

Thank you for the post! I actually have a PVC clipper tool (I've done some landscaping in my time). The leak is strange; if I am parked on flat level ground the leak comes from the front of the tank under the cab. If I am park on an incline with the front of the truck pointing uphill, the leak still comes from the front of the tank under the cab (when it is full). I hope I don't have a crack in it. It only happens if I fill it all the way up, so It won't be until it is fixed.

 

Like I said the vent tubes highest point is at the rear of the tank but it has a connection to the front of the tank as there is a high point there that is vented as well to the back. My guess is the connection there is loose and the leak comes from there when you fill it up and the presure forces it out.

You can't check/see it with the bed off, you will have to try and reach up there to feel around to see if it is loose. It extends pretty far forward under the cab body. Maybe a mirror and a light would work.

Go get em'.

 

I see what you are saying... (little slow this morning!!) I figured it is going to be a PITA to get too, or at least see what I am doing. I have been wanting to harpoon my tank to get that extra 4 to 5 gallons. This way I will tell my wife I have to remove the bed to get to the leak then I will harpoon the tank. She doesn't understand why we work on our trucks when they run fine. I don't understand why they buy shoes when the closet is overflowing with them. Oh well. Thanks for the input!!!

 

Very nice writeup Bill - dont plan to do this but i can appreciate the effort involved in the write up and pics

 

Thank you for your input Bill. I will have the instructions printed out next to me so I don't mess up! I haven't look yet but are their plugs for the tail lights when I remove the bed?

 

Yes, there are plugs in the rear for the tail lights, license plate lamp, and trailer plug. You'll find them easy enough.

I'm not quite following Lonewolf, but that's probably just my slow thinking. So I'll just add my $.02 on top of his.

The top of the tank is kind of like a saddle - high on both ends, and low in the middle. In the low area in the center is the big bung hole with the sending unit and pickup. From your description of the leak it's not leaking there.

On each high end of the tank is a breather vent. They each have a check valve so that air can get in while you use up the fuel. But they don't let air or diesel get out - at least not normally. The vent hose from those goes up under your cab like Lonewold described.

But you said it was leaking from the top and running down the end of the tank. So I don't know what that has to do with the vent lines under the cab. I can see some diesel getting out the breather vents while sloshing around during while driving, but why would diesel come out of the breathers while you are sitting at the filling station? Because of the high ends on the tank, it is impossible to fill up to the point where fuel is coming out the breathers, especially if you have not yet harpooned it. So even if one of the breather vent hoses came off, I don't see it leaking while sitting still. But then, I could easily be wrong about that.

You could have a bad check valve in the breater vents. From memory those looked like they were glued in the tank and not replaceable.

You could have a cracked tank.

Or it could just be a loose connection of the fill tube and fill vent tube.

 

I did this mod about 6 months ago and have yet to have any spills or leakage from filling to pump shutoff or sitting in the hot SoCal sun during the summer (we've had a heat wave this summer). I originally had a concern about fuel spillage and read several posts where they had a friend that had a problem, but I never had anyone tell me (that has done it) that they had a problem. I was already in there for fuel system mods (a common problem on our elderly 7.3s) and took the extra 15 seconds to clip the filler and vent tubes as high as possible. I now go almost 550 miles on a tank before I refill. Well worth the time and effort, although I wouldn't recommend dropping the tank just for that unless you're bored or have PMS as bad as I do.

BTW you can pick up a PVC cutter at Home Depot for $10 or at Harbor Freight for $5. SSSOOO much cleaner to clean up and a nice, tight and clean cut in seconds. I highly recommend using one instead of a hack saw. Just my .02

 

When I crawl under the truck I can see the diesel coming down just to the right of the front strap that holds the fuel tank in place. Unfortunately it is right under the cab and not the bed. You guy's have given me a whole bunch of good info so I can fix it (just have to line up the neighbors to help). I just won't fill it all the way up until I have fixed it. I would rather take the bed all the way off. Do you have to unhook the fuel lines or can you leave them on?