Farmall Cub

Can someone identify this plug on the side of the oil pump? And its purpose? Looks like a drain plug but it is at the top of the pump assembly. I couldn't find it in the Parts Manual or the Service Manual. Mostly curious.





Also, must the oil pump be reprimed if the engine and filter have been drained of oil?

Thanks, Dale #2

Been a long time since I have had an A pump in my hands. That said, I believe that the pump is cross drilled through that hole to make the oil passage from the output of the pump proper to the vertical passage that carries oil up to the block. The plug simply caps off the end of the passage.

If you have simply drained the oil for a change, priming the pump shouldn't be needed. If you have removed or disassembled the pump, you need to make sure you have a good amount of oil or assembly grease in the gears of the pump.

Thanks Jim! I hadn't thought about a production-only reason for the plug...makes sense.

Also, didn't think I needed to prime, but since I have been reading more and more of the forum info, including folks getting long-stored tractors running, I got a bit paranoid!!! Have a good day.

Dale #2

You want to be sure the bottom plate of that pump is straight or it doesnt seal properly with the paper gasket. no sealer, as that gasket sets the clearance for the pump gears.

Thanks, guys. I actually only replaced a missing cotter pin on one of the connecting rod nuts, visually checked everything, made sure the pump screen was clean, and since the pan had already been painted with primer, I reinstalled it with a new gasket so I can prime the entire tractor. Hopefully I will then put RED on him so I can start putting components back on. SHOULD I have done anything to the oil pump? This engine was running fine when I started tearing him apart. (We'll see if it ever runs again!!)

Dale #2

it's probably fine, i wouldn't worry if it ran good and carried decent oil pressure before.