Diesel Leak

[rloaderro]

I have a pretty bad diesel leak, but not sure where it's coming from. Maybe someone is familiar with where it could be. It's a '79 BJ40 just back from having some work done on the transfer. When I picked it up the mechanic said there was a leak because the hose that connects the fuel line to the tank was deteriorated. He had clipped off the bad part and we didn't see any fuel leaking at the time.

Yesterday arrive at work and lots of diesel is dripping from the underside. There is so much I can't tell where it's coming from. The hose itself and where it connects to the tank is dry. Pretty much everything from the tank to the exhaust on the driver-side of the truck is wet.

My best guess is it's coming from the top of the tank - might have to take the whole thing out . When the engine is off the diesel stops dripping after a while. So, how dangerous is this? I know diesel doesn't burn like gasoline. Also how bad is this - is it going to corrode away the bottom of the truck over the next few days?

I'm not a mechanic and not particularly smart or clever so any advice or suggestions welcome .

 

[dargreg]

Looks like its comeing from the top of the tank maybe your mechanic helped another corroded part of the line to fail. I would asume that it is return fuel though as it would not run if it was suction.Not a big deal to pull the tank.

 

[singletrackjunkie]

diesel won't corrode, if anything it will protect your undercarriage. Try posting on the diesel forum, may have better luck there.

 

[dargreg]

Ya but he doesnt want diesel all over his under carriage ,Air and salt will corode the outside of the fuel line especially up in that area where it never gets cleaned off.

 

[lostmarbles]

When I picked it up the mechanic said there was a leak because the hose that connects the fuel line to the tank was deteriorated. He had clipped off the bad part ...

My guess is that he may have damaged your rubber fuel hose (in your photo) and perhaps had to shorten it to remove the damaged part. ...........Where is the hose clip? ...........Maybe he accidentally left it off in the process?



(I can't see much sign of corrosion under your cruiser. In fact it looks to be in great condition!)

...rrive at work and lots of diesel is dripping from the underside. There is so much I can't tell where it's coming from. The hose itself and where it connects to the tank is dry. Pretty much everything from the tank to the exhaust on the driver-side of the truck is wet....

Well, as I say, maybe your mechanic forgot to put the hose clip back on when/if he shortened that rubber fuel line.

But like dargreg said - It shouldn't really run with a fuel leak there. That is definitely the suction side of your fuel pump (because there is no "return line to the tank" on a BJ40) so by rights it should be admitting air (rather than leaking diesel) and this would normally cause your engine to stall and prevent you from restarting it..... But perhaps your tank is so full of diesel that that area is under pressure instead of vacuum?

..My best guess is it's coming from the top of the tank - might have to take the whole thing out .

I think you need to confirm with your mechanic exactly what he "clipped off". (I suspect he caused the leak.) ...And/or check that hose yourself.

Perhaps the "apparently missing hose clip" may be responsible for your leak. (Check if the clip is missing and whether the hose is tight or loose on the tubing?) If the hose is missing its clip (and perhaps also too short), you will have a simple fix on your hands.





PS. Diesel fuel won't corrode, and is not highly flammable. So "MESS" is the only real immediate problem associated with your leak (unless/untill air enters your fuel line). But you obviously still need to get it fixed ASAP.

PPS. IF a fuel hose is perished, cutting off the leaking section is not a professional/acceptable fix. You need to replace the hose with quality fuel hose of the same length as the original (not shorter). And if you find that hose is perished, replace the ones in the engine bay at the same time because they are likely to be the same age and perished also.

 

[rloaderro]

Thanks lostmarbles and everyone!

I will definitely add a clip to the hose. The mechanic showed me a section of hose about an inch long that he had taken off. I don't think the problem is the hose - if you can see from the photo the hose itself is completely dry - if the diesel was coming out of there some part of the hose would be wet, in fact I would expect fuel to be dripping down the entire line.

The body of the cruiser is in pretty good shape more or less. I worry that the tank may have been rusted and simply painted over when I bought it.... now a few months later the diesel has eaten through the paint and is leaking. Pure stipulation and i've never been right before about these kind of things so...

I'm going to try to wash the undercarriage, let it all dry then take it for a span around the block to see better where it's coming from.

 

[lostmarbles]

Could be that your mechanic broke the metal fuel line (where it exits your tank) when he was fighting with the hose?

Sorry - I don't have too much confidence in someone who shortens a line like that and leaves off a hose clip too.

And when a fault develops straight after recent work - I always associate the two (and am correct MOST of the time - but not all the time).

I suggest you pressurise your tank with someone underneath to check where the fuel comes out.

Here's how I pressurised my tank using an air gun and motorcycle handgrip:

 

[rloaderro]

It turns out the person I bought the cruiser from, had switched out the original bench for a pair of normal seats. In the process of drilling the seats in.... well I bet you can guess where this is going

 

[lostmarbles]

My apologies to your mechanic for pointing the finger at them

It is amazing how many people drill a hole by pushing hard on the end of the drill without holding it is such a way that they can prevent drilling further than intended (which involves "feeling for the break-thru point" of course).

What a PITA to fix!