Ford 841 engine oil pump

[Ddaland]

Recently was running my 841 into town when I completely lost oil pressure- spun a rod bearing. On Disassembly, no obvious signs of damage to the oil pump other than the hex drive shaft had a fair amount of wear on it- I replaced it. The one thing I couldn't check was the pressure relief valve- I assume that it's under the plug.
Replaced the lower end bearings,and reinstalled the oil pump after spinning it up using a drill- definitely pumping oil. Still not reading any oil pressure though.
After pulling the oil filter. Cranked over- it is getting oil to that point.
Interestingly, when the tractor is parked nose downhill it does show 5-10 psi on the guage.
Thinking about replacing the pump unless someone else has a better idea

 

[Bern]

If you had oil pressure one moment and not the next, it is not very likely to be an issue with the pump. If you're getting no pressure now, and yet the pump is moving a good quantity of oil, I would suspect that you lost a cup plug on the end of the oil gallery. At least that's my first thought.

I suppose it's also possible that the relief valve spring inside the pump broke. Seems like a longshot but anything is possible I suppose. I'll assume that when you had the pump off you removed the cover and inspected the gears. With the gears out I believe you can take an angled pick and check to see if the relief valve is under spring tension. If it flops around or shakes like a baby rattle, you have a broken spring.

If it was in my shop I would pressurize the lube system with my remote pump. If it doesn't build any pressure I would lean towards my first idea. If it does build pressure, something is likely wrong with the pump.

 

[Ddaland]

(quoted from post at 18:17:12 08/30/22) If you had oil pressure one moment and not the next, it is not very likely to be an issue with the pump. If you're getting no pressure now, and yet the pump is moving a good quantity of oil, I would suspect that you lost a cup plug on the end of the oil gallery. At least that's my first thought.

I suppose it's also possible that the relief valve spring inside the pump broke. Seems like a longshot but anything is possible I suppose. I'll assume that when you had the pump off you removed the cover and inspected the gears. With the gears out I believe you can take an angled pick and check to see if the relief valve is under spring tension. If it flops around or shakes like a baby rattle, you have a broken spring.

If it was in my shop I would pressurize the lube system with my remote pump. If it doesn't build any pressure I would lean towards my first idea. If it does build pressure, something is likely wrong with the pump.

Sorry, did not make one thing clear- rotary pump instead of Gear driven

 

[Bern]

Doesn't matter, gear or gerotor, my recommendations are the same.

 

[JMOR]

(quoted from post at 08:52:04 08/31/22) Doesn't matter, gear or gerotor, my recommendations are the same.

hat is the possibility that when "nose down hill" that the oil level rises high enough to cover a suction side air leak?

 

[Ddaland]

Before I get tearing things back down this weekend.... Where are the galley plugs located? I assume they must be somewhere under the front cover- since I'm not seeing any oil leaks- or is there any way of seeing from the bottom with the pan off?

 

[JMOR]

(quoted from post at 15:28:33 09/01/22) Before I get tearing things back down this weekend.... Where are the galley plugs located? I assume they must be somewhere under the front cover- since I'm not seeing any oil leaks- or is there any way of seeing from the bottom with the pan off?

ehind the camshaft gear and same position behind flywheel and cam/hyd pump drive gear.

 

[Ddaland]

Guess I better hope if that's the problem it's a front one....

 

[Eman85]

I'd guess if it was the back one oil would be leaking out of the bellhousing drain hole.

 

[JMOR]

(quoted from post at 10:30:32 09/02/22) I'd guess if it was the back one oil would be leaking out of the bellhousing drain hole.

ould be on 8N, but pretty sure the plug in inside the area contained by the hyd pump drive gear cover plate, so it would just flow back into engine oil pan on this engine.