Fuel leaking from the fuel tank/sending unit on top of the tank

[FlatTwin]

I have a 2002 2500 and the last several months have had a puddle underneath the fuel tank. It appears to be coming from the top of the tank, either one of the connections on the sending unit or maybe the gasket that holds the sending unit on? 

 

Have had the top of the tank off before (pulled the bed) and at that time put the Vulcan 1/2 inch fuel line and draw-straw in the truck. 

 

Anyone ever had an issue with this sort of thing? 

 

After pulling the bed the last time, am thinking of just pulling the tank this time as the bed was not that easy but then I am working in the driveway.... 

 

Ideas or suggestions or anyone ever had this issue before? 

 

Thx, 

 

FT

[YabbaDoo]

The tank isn't hard to drop in the driveway... Just make sure it is close to empty

[rancherman]

take a  floor jack,   and  remove the saddle.    then  cut a  chunk of  2X6  just  shy of  the distance between the  tank mounting straps.     bore a hole in the center of  the 2x6  and  bolt it  to the floor jack... through the   saddle  hole.

 

Then   jack the board up against  the  tank... and  lash the tank down  with a couple of  ratchet straps.     undo  your   plumbing, electrical, and   the  straps and lower away!

 

I've  'freehanded'  it too many times..   and  just a couple  gallons  running to the  low side is  enough  to pitch the whole thing  off  my   'knee scissors  lift'  LOL 

 

If ya got a buddy,  then  this ^^^^   is  probably  overkill,  but  it  works  fine  by myself

[Cowboy]

I currently have this same issue, though the top of my fuel module is very... 'Custom' so I doubt it's the same issue.

 

If you've got a buddy, I take two ropes/straps, hook to the passengers side frame, run them under the tank, and then over the drivers side frame.  Loosen up the tank hold down straps, and tell the buddy to lower her down.  Otherwise I just balance the thing on my knees while laying under it.

 

For finding a leak, you might be able to get away with taking out all the drivers side bed bolts, and loosening all the passengers side bolts about a half dozen turns, unhook the filler neck, and any electrical on that side, then just tilt the bed up till you can see.

[JAG1]

I cut a access hole over the top of the fuel module in the bed. It's really very nice to be able to get in there and have the module out in about two minutes. But..... and I mean a big BUT.... it took me two and a half days of iron metal framework to reinforce what I cut. Plus every bit of design skill/thought to work it out. When I cut the hole, I thought,'Oh! how cool is that! 'but like said before, it was a real brain racker to fix it back strong again. Especially when knowing I cut thru a bed frame support and carry a heavy slide in camper.

The only way I can show how is to actually show it to you and not in a post. Be glad to have anyone come by for coffee too, if you like.

It first takes the right amount of numbness or guts, whichever you prefer, and then some real work/ brain work too work it out.

Maim reason for doing it...... I love a good challenge, had time on my hands and one day age will make things like dropping the tank difficult.

Edited January 25, 2015 by JAG1

[Dieselfuture]

I usually put two straps diagonal in side the bad and use engine hoist extended all the way out passed last hole, few inches in yet. But I do have a short box. I might go get a piece of square tubing that's a foot longer for this job later if I do it again. Obviously safety first

[Dieselfuture]

Here is my module that has draw straw 5 and my own return all in 1/2". I tried 3/8 in return before and pressure fluctuated to much, all in 1/2 1-2psi idle to full throttle.

[JAG1]

So you are saying you got  1 to 2 psi less pressure fluctuation by going to 1/2 inch return lines?..wow!

Edited January 25, 2015 by JAG1

[rancherman]

Nice work  dieselfuture.      I see you  dump your return  clear to the bottom..  right beside the  uptake tube.    

[Dieselfuture]

So you are saying you got 1 to 2 psi less pressure fluctuation by going to 1/2 inch return lines?..wow!

I'm saying my total fluctuation is no more than 2 psi with 1/2 return where before, when I used quick connect that was 3/8 and inside more like 5/16 it would be as much as 4psi. That's what I drilled out and put jic fitting in. here is before and after. That white stuff is JB Weld rated for fuel, didn't need it but put it for support. It bonded pretty good. I got a piece of it in my glass jar with diesel in it along with a piece of hose that I used for lines, just seeing how long before it brakes down, so far solid as rock.

Edited January 25, 2015 by Dieselfuture

[Dieselfuture]

Nice work dieselfuture. I see you dump your return clear to the bottom.. right beside the uptake tube.

Thank you. When it's installed in tank I got about 1/2 gap to bottom, I did a little experiment with it and at first I had it just in the basket, and that made it foam, so I redid it and no more foaming when it's submerged in fuel. I did this test in 5 gallon bucket, tricky part is to cut it to right length, if you pull tank out and set it on floor instead of using straps depth changes a little. When I did mine I had 3/4 of fuel it tank.

Edited January 25, 2015 by Dieselfuture

[JAG1]

That says quite a lot about fuel restriction coming just from the fuel return. Wonder how that affects the overflow valve and VP cooling we all talk about.?

 

Another mod I need to think about as I'm getting about 4-5 p.si. fluctuations with heavy hauling uphills.

 

This good information Dieselfuture.

Edited January 26, 2015 by JAG1

[Dieselfuture]

That says quite a lot about fuel restriction coming just from the fuel return. Wonder how that affects the overflow valve and VP cooling we all talk about.?

 

Another mod I need to think about as I'm getting about 4-5 p.si. fluctuations with heavy hauling uphills.

 

This good information Dieselfuture.

Actually that return line I was talking about is for Air Dog not for VP, VP and Injector return is still in original place with a clip in connector, which is even smaller about 5/16 OD and 1/4 id. But I see your point if a guy can up size that too then maybe it would help VP also. 

[JAG1]

You saying the AD150 has it's own fuel return? I did not know since I have the AD100 without any return.

Is that part of how it regulates pressure dumping excess back to the tank?

Thanks Dieselfuture.

Edited January 26, 2015 by JAG1

[Dieselfuture]

You saying the AD150 has it's own fuel return? I did not know since I have the AD100 without any return.

Is that part of how it regulates pressure dumping excess back to the tank?

Thanks Dieselfuture.

Yes ad150 has return to tank and mine is regulated with ball and spring, It used to be returned to filler neck but I had problem with 1/3 tank sucking air, so I got draw straw 5 and returned it to fuel basket. Some people don't seem to have problems and some do, but I'm not sure if they realize that with nidle valve mostly closed to keep sensors from getting hammered, it won't show up on gauge as easy, to test if you do have problem with 1/4-1/3 tank issues you need to open nidle valve up so it moves instantly. If you notice before and after pictures I already had 1/2 line there, it was the fitting to module that was restrictive. That fitting is original outlet for In tank pump and when you get draw straw 5 they tell you to use it as return. I was on the phone with Vulcan for few weeks and finally did it my way and it worked great, I called them back and said that they need to include another bung fitting with their kit in1/2" so people can return it to fuel basket and won't have these problems, the guy seem to understand what I was saying and say it's only happens with AD150-165 I was like yeah, and... So they know, not sure if they will do anything about it. Edited January 26, 2015 by Dieselfuture