justagoodolboy

What is the best manner to check for air leaks in my fuel supply lines? Should I litterally start at the pickup tube in the tank? Just trying to form a battle plan for the weekend and did not return much info via searching....

Stihl

Pressurize the fuel tank a little and see if it squirts out anywhere

justagoodolboy

I've always heard there is no such thing as a dumb question so I'll ask - how do you pressurize the tank? I could see a rag mashed around my hose from the compressor to seal it off pretty well, but is that good enough to test for leaks?

Anyone else?

Thanks Stihl!

sdstriper

Maybe someone can expand on this. There is a method to put a vacuum gauge in the fuel line before the lift pump to detect for air leaks. I do not know the exact procedure but thought I would mention it... Hopefully someone can clue us in or correct me if I am wrong!

archer39

yep, that will work.

You can also use clear hose between the lift pump and injection pump. This will allow you to see air bubbles in the line.

wannadiesel

A word of caution when pressurizing the tank - you only want a couple psi, a shop rag wrapped around your air nozzle stuffed in the filler tube and a little pssst is all you need. Put 10 psi to it and you will have a BIG leak.

justagoodolboy

Thanks for all the input. I ended up using a piece of rubber and work clamped it over the fuel hole. Then poked a small hole in it and pushed air in their with my compressor. I was actually suprised as the hole let air in but did not let it out - guess I got the hole "just right".

No leaks found though. Not sure whats going on with my truck.

Trooperthorn

Mine had mostly steel lines. All but a little hose at each end. I took a shot and replaced the 12 or so inched between the hard line and the lift pump and cured my problem (actually the hose at the other end was already brand new). Even upon inspection, I could see no hole or split, only a small point that looked like a dimple. However, air can travel through a passage that oil cannot, and the act of pressurizing could cause a flap of rubber on the inside of an old hose to seal rather than leak.

Replace the hose at the lift pump, at least then you can take it out of the equation.

SUPRDUD

I had one where the steel line had a wear hole in it along side the tank. All full of mud and gravel.....would only leak when the tank was very full and led to a "no start" eventually. Bypassed it with a length of the correct hose and all is happy!

justagoodolboy

Interesting Note - my truck has ALL plastic/rubber black lines. Nothing is steel. Should that tell me anything? They actually looked in good shape.

wannadiesel

The later trucks with the plastic lines tend to leak at the fittings. The o-rings in the quick disconnects get tired and start letting air in.

Taylorm2121

what do you recommend on how to fix issues with the stock plastic fuel lines?