Fuel line connector problem

   / Fuel line connector problem #1  

Tibbits

Bronze Member
Joined
Aug 19, 2007
Messages
74
Tractor
L3430 GST, BX1500
The top of the fuel tank of a Kubota L3430 has 2 fuel lines connected - one routes to the injectors and one to the fuel filter. There is a nipple for each hose sticking out of the fuel tank to connect the fuel lines.

Well, I noticed a slow leak on the line that connects to the fuel filter, and when checking it I discovered the nipple is broken (on the fuel tank) and just dangling. The parts diagram seems to show the nipples as part of the fuel tank? I don't want to replace the fuel tank!

Has anyone had this problem and how did you solve it? I'd like to find a way to 'fix' the nipple and connect the hose without a lot of time or money involved. Some type of 'screw in' nipple would seem to fit the bill.

As background, this fuel line does not seem to be needed a lot. I think it exists to relieve excess pressure from the fuel filter. I only notice a small leak when I fill the fuel tank completely full, so I assume some leaks out the broken nipple as the fuel sloshes over it. I'm more concerned about keeping dirt out of the tank than the little bit of fuel that leaks out. Any ideas (other than a new tank!) would be appreciated.
 
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   / Fuel line connector problem #2  
Does it have a cap big enough to get your hand in (or most of the way in) the tank? If so look for a bulkhead connector. Drill the right sized hole, they use a jam nut inside the tank to seal, put the right fitting in to mate to the hose . Make sure the hood will clear.

Plug the old hole with an automotive gasket maker that is diesel resistant.
 
   / Fuel line connector problem
  • Thread Starter
#3  
I like that solution, Argosy. but I'm afraid I don't have enough room with the cap opening to work with. I'll check I'm the morning.
the gasket maker might get me by. since this is just an over flow line and rarely carries fuel, I may be able to glue a fitting to the existing hole with the gasket maker. might work. and if doesn't, no harm done. thanks.
 
   / Fuel line connector problem #4  
I'm a little confused...the line to the filter is the feed, I would think, and the other is the fuel return line.

Hard to believe you won't have to remove the tank, at the least to address this.

If you are looking for a shade tree solution, perhaps you might connect the good nipple to the fuel filter line, block the other nipple, and re-route the return line somewhere into the tank ...say, at the top near the filler.

I'll look at my shop manual (L4330) in a bit and see if that helps ...

still, once the tank off/accessible, there are solutions that can insert a new fitting from one side only
 
   / Fuel line connector problem
  • Thread Starter
#5  
The broken nipple appears to be the 'fuel filter air vent pipe' shown on the diagram. The only time I have noticed any leakage was when the tank was full, so I'm thinking a quick fix may be OK...as long as it doesn't leak and keeps dirt out.
 

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   / Fuel line connector problem #6  
Plastic weld it?
 
   / Fuel line connector problem
  • Thread Starter
#7  
not familiar with 'plastic weld' but I think I might be soon.
 
   / Fuel line connector problem #8  
Permanent repair?If you don't like plastic weld, Have you considered tapping out the hole with a pipe tap and screwing in another nipple for the return line?There will be a few shavings, but use soft grease on the tap and clean it often. Pipe taps match screw in nipple fittings. Just a free thought?
 
   / Fuel line connector problem
  • Thread Starter
#9  
I really think the tap method is best. now, to find a fitting with threads and male connector should be fun!
 
   / Fuel line connector problem #10  
(sorry about my post, above...didn't realize the hose came in at the top...vent/return)

as for tapping, my tank would be too thin to get any/many threads so holding would be a problem ...and, despite some advertisements there don't seem to be any adhesives/epoxies, etc. that are designed both for the plastic and for fuel (at least, gasoline) ...heat welding is how it would be done, but that seems out of the OP's range. Rather than tap, it would be ideal to use a nut on the back-side (i.e., inside) but as currently located, I'm guessing that holding the nut through the filler opening would be problematic.

I might consider patching the current hole (maybe tapping and patching with some epoxy or other fuel gasketing mush and then relocating the fitting to the top of the tank, reachable through the fuel-filler opening ...using a right angle fitting threaded on the inside and with fuel-resistant washers on inside and outside.
 
 
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