Engine driven fuel pump IO-540 D4A5

[T Carey]

Have noticed oil leaking from a line connected to the rear of the engine driven fuel pump. The line ends at the bottom rear of the nose gear wheel well, flush with the belly of the aircraft. Does this indicate failure/pending failure of a diaphragm? Should the fuel pump be rebuilt? Or could something else be the culprit? Seems to push more oil when oil level is above 9qts, but rate is excessive regardless, around 1qt/1.5hrs - 9qts or more & 1/2qt./1.5hrs below 9qts. Type of flight is x-country. Not blowing oil from breather tube. Engine = IO-540 D4A5 Any insight appreciated, thanks.

[Ben Ayalon]

Yes, the diaphragm is ailing and it is time to replace the pump.Oil should not come out ofthe pump. I don't know if you can re-build it or not.

Don't wait.

Ben

[T Carey]

Thanks Ben, while reading the service manual I noticed the fuel pump has an o-ring that I suppose, once becomes worn enough allows oil to bypass and then evidently exit through the line. Indicating, as you have stated, it's time for a replacement pump.

Chuck

[Ray B]

The reason for the tube on the engine driven fuel pump is to direct gas out of the engine compartment if the diaphragm starts to fail. It also keeps it out of the engine case/oil sump. In any case DO NOT fly with a questionable/leaky fuel pump (unless your looking for a reason to try out that new fire extinguisher). Ray B