M7040 sudden fuel line separation

[Dave M7040]

In my area a major storm is coming and because my wife is very ill, I was readying the M7040 and blower so I could keep our lane open for medical supplies or an ambulance.
I backed the tractor out of its storage location and was getting ready to drive it into my heated work shop. When I got out of the cab to open the shop door I noticed large quantities of a clear liquid dripping unto the ground from between the rear of the engine and the fire wall. The loader made it impossible to see but I feared something major happened to the steering valve.
When I got the loader off and was able to see, I noticed a fuel line leaving the injection pump had separated from a plastic check valve and fuel was pouring out.
The check valve had no raised portion on its nipples to help the wire clamp hold it in place.
The check valve and inside of the rubber fuel line were cleaned with brake clean and a much more robust spring type hose clamp was installed.
Owners of similar machines may wish to review the condition of the clamps and check valve and avoid a bad scare.

The check valve is used because the return line just dumps into the top of the fuel tank and without the check valve the injection pump could inhale air from the tank when the engine is stopped.
Other tractors I have known have the return line extend to the bottom of the tank so the open end of the return line is always submerged.

Dave M7040

 

[thclimer]

Thanks for the picture and I identifying what you were describing in it, very helpful to understand your issue.

I hope your wife recovers from her illness and is not in need of an ambulance.

 

[thclimer]

If you need a stronger hose clamp they make what are called "fuel line hose clamps"

 

[jonsstihl]

any chance the "Barb" broke off the check valve and thats why you didn't see it. It may be still in the hose.

 

[ruffdog]

Was the separation right before the check valve or right after? I'm just wondering why there would be that much pressure on a return line. Is the line kinked or pinched going back to the tank? Is the tank properly vented? Did the check valve get froze or plugged?

 

[Dave M7040]

any chance the "Barb" broke off the check valve and thats why you didn't see it. It may be still in the hose.

No barb does not exist on these valves. Plastic end was smooth and unbroken.
Judging by the simple wire clamps Kubota uses all along this return line they are not expecting any pressure.
I never have water issues with my fuel but that does not mean condensation coming back from the tank affected the check valve.
I made the post so if another owner is suddenly faced with leaking fluid they dont panic like I did when in the end it was just a simple problem.
I understand from my dealer they have seen this on other M series machines.
The line came off on the IN side of the check valve
Dave M7040

 

[oosik]

Dave - I hope your wife is better soon.

AND - BTW - I had the EXACT same thing happen on my M6040. Kubota uses those worthless spring tension clamps. Service tech came out and replaced the spring tension ones with ones like thclimer pictured. Problem solved.

 

[Dave M7040]

Dave - I hope your wife is better soon.

AND - BTW - I had the EXACT same thing happen on my M6040. Kubota uses those worthless spring tension clamps. Service tech came out and replaced the spring tension ones with ones like thclimer pictured. Problem solved.

Thank you, unfortunately my wife's condition will only get worse.
Dave M7040

 

[rwskinner]

Those little "check valves" have short, smooth, tapered fittings. I fought this and thought I won but then eventually you find all your $$$ diesel is going on the ground.
To fix it, I used new Kubota fuel line, and spring clamps like Briggs and Stratton uses. It was too small for true hose clamps. Never a problem since then.

Fuel line is fuel line, but I tried new fuel line, and it just wasn't gripping the valve very well. The Kubota fuel line fits great.