A nifty tool for fuel leaks....

[pctrans]

Came up with this idea for all you guys trying to find air leaks in your 800 series truck fuel systems. I know a lot of guys have problems with the IP losing its prime, so just pressurize one of the tanks, and look for leaks in the system. Some are hard to find, but wet hoses/connections make it a lot easier to fix.

 

[Chieftawny]

Nice idea!

 

[KsM715]

I had read about pressurizing the system and was trying to figure out how.

Thanks.

 

[Chief_919]

Came up with this idea for all you guys trying to find air leaks in your 800 series truck fuel systems. I know a lot of guys have problems with the IP losing its prime, so just pressurize one of the tanks, and look for leaks in the system. Some are hard to find, but wet hoses/connections make it a lot easier to fix.

Yep, all the vehicles in my maintenance platoon have caps done like that so we could swap them on a vehicle we needed to troubleshoot.

However, we found that for safety you need to have two things- a valve to release the pressure first, so yhou can release the pressure before removing the cap. Otherwise then the tank is full you risk a spray of fuel. The second is a pressure release valve at about 5-8psi. Without that you risk ovepressurizing the system, and a system designed for low pressure or even to run at a negative pressure can develop a lot more, and larger leaks quite fast with too much pressure.

 

[jcappeljr]

great idea,better than using a rag and a air hose.

 

[pctrans]

Note: the cap is not perfectly airtight. I just put the air chuck on for a couple seconds. That is long enough for any fuel to seep out any cracks. The air in the tank leaks out around the gasket on its own, so no problem with fuel spray.

 

[drgreg]

I think your cap would be a great tool. Just check the pressure before opening, makes sense. Good work.

 

[wreckerman893]

Anybody that has ever ran a two stroke Driptroit out of fuel can appreciate that design.

I carried one for years when I drove a Freightliner with a Detriot in it (not that I ever ran it out of fuel).

 

[stumps]

Anybody that has ever ran a two stroke Driptroit out of fuel can appreciate that design.

I carried one for years when I drove a Freightliner with a Detriot in it (not that I ever ran it out of fuel).

Hey! It's not leaking, it is just marking its parking space.

-Chuck

 

[eldgenb]

I always took off the vent line and stuffed my blow gun to the tank side and it has always worked great.

 

[Hammer]

I always took off the vent line and stuffed my blow gun to the tank side and it has always worked great.

Yup, this is what I do. It won't hold air in the system, but holds it enough while it bleeds out to find the leak.

 

[eldgenb]

Yup, this is what I do. It won't hold air in the system, but holds it enough while it bleeds out to find the leak.

I have a pen style air gun that you twist and has a pencil style nozzle, I twist it so the pressure is low and jam it in the rubber hose. It will keep it under pressure as long as you need. On my 5 ton's I always ditch the selector valve if it has one and replace all the soft lines(cheap insurance for problem free operation) disconnect the line from the ip and blow fuel through the filter and up to the pump before I crank it over. Works great.