Cat 941 Fuel Leak

[Rspann]

Cat 941 sn80h2530 which is leaking fuel at the vent hose. Machine runs fine just pouring fuel (approx pint a minute) out vent hose. Problem started after changing filters. Have changed out the vent control knob. Tried adding a shutoff on the vent hose which caused the fuel to leak between the transfer pump and hour meter that attaches back of pump. The fuel system does not have fuel return line back to tank therefore confused how system works for over pressure. Also has no check valve only output is fuel pressure meter. Trying to understand where check valve are located in this design. My first heavy equipment so having to rely on service manual which is vague in this area. Any help would be appreciated

 

[Bob/Ont]

If it didn't leak untill you changed he filter and opened bleed valve to purge air then the bleed valve is likely your problem.
Don't plug tube, you are backing fuel up through the pump shaft seal vent tube. The max fuel pressure relief valve is in the transfer pump. It relieves pressure to the suction side of the pump.
Later Bob

 

[Rspann]

Thanks for the feedback. I changed the valve stem but not the valve body. Will try this next. If that does not fix problem do you know if the transfer pump can be rebuilt or does it have to be replaced?

 

[d9gdon]

Thanks for the feedback. I changed the valve stem but not the valve body. Will try this next. If that does not fix problem do you know if the transfer pump can be rebuilt or does it have to be replaced?

Rebuildable:

 

[Rspann]

Sorry for the late response back. Well finally got around to rebuilding the transfer pump. New seals, plunger, spring, etc... Also replaced the bleed valve and associated seat. Still did not fix the fuel leak. With the engine off still have fuel dripping from the bleed vent hose unless a shut fuel off at the tank. With engine running have stead stream (about pint of fuel/5 min) coming from the bleed vent hose. Dont have diagram of actual fuel flow from tank to injector pump so not sure if I am missing a stuck open check valve. Also was wondering if fuel could be coming thru the manual primer pump and be causing the problem. Loader runs great with the exception of this constant fuel leak. Starting to wonder if might not be easier to pipe the vent hose back to fuel tank and quit worry about the leak.

 

[flmason]

I have same problem with my 941B. Pouring fuel at the vent. Rebuilt transfer pump, cleaned and resealed fuel filter assembly. Still leaking. Help.

 

[Brent Wilson]

Hello I have a 951c 3304 engine doing the exact same thing did you ever find out what the issue was?

 

[kshansen]

Hello I have a 951c 3304 engine doing the exact same thing did you ever find out what the issue was?

Brent,
Might be best to start your own thread on this problem and as always the best thing would be to include a full s/n right up front. Next some idea of when it started and anything you did to the machine before the problem showed up or anything you have tried to fix the problem.

Describe the problem you are seeing and not just say it doing what those other guys machines were doing.

A picture or two of the area where the problem is would also be helpful as many times someone will see something just off to the side that will be a major clue.

 

[Warren Ashley Hall]

Sorry for the late response back. Well finally got around to rebuilding the transfer pump. New seals, plunger, spring, etc... Also replaced the bleed valve and associated seat. Still did not fix the fuel leak. With the engine off still have fuel dripping from the bleed vent hose unless a shut fuel off at the tank. With engine running have stead stream (about pint of fuel/5 min) coming from the bleed vent hose. Dont have diagram of actual fuel flow from tank to injector pump so not sure if I am missing a stuck open check valve. Also was wondering if fuel could be coming thru the manual primer pump and be causing the problem. Loader runs great with the exception of this constant fuel leak. Starting to wonder if might not be easier to pipe the vent hose back to fuel tank and quit worry about the leak.

 

[Warren Ashley Hall]

Did you ever resolve the fuel leak problem? I'M having
the same issue On a 941 B

 

[Warren Ashley Hall]

I have same problem with my 941B. Pouring fuel at the vent. Rebuilt transfer pump, cleaned and resealed fuel filter assembly. Still leaking. Help.

Did you ever fix this problem?

 

[charles walton]

Did you ever fix this problem?

Powder Springs Ga.?