[5540jd]

Only way to drive pump is by turning flywheel which turns camshaft which turns driveshaft to oil pump. You can unplug spark plug wires and use your electric starter and watch to make sure pump shaft is being turned and nothing slipping. Filter housing can also have holes in it from years of condensation forming, but yours looks pretty good from the pictures I saw. I had to replace mine on my A from to many holes.

 

[5540jd]

Normal wear in the engine and pump will cause oil pressure loss. The main bearings on these tractors have shims on bearing caps to allow adjustment as the engine wears. These are also on the connecting rod caps as well. You’re service manual should cover this in detail. They may need to be looked at to ensure they aren’t getting to loose. You may need to redial oil pressure if you end up removing any shims.

 

[5540jd]

As for your air filter canister, I would clean off the rust best you can and make sure to apply some oil to it. The tractor running and moving should splash enough on it to keep it oil covered and prevent the rust from reforming. Make sure the bowl is filled to the proper level. Not getting tan very much May have caused some of this.

 

[5540jd]

I think you will find that pulling the hood is the best way to get canister off tractor. May not be worth it. You’re probably going to find something else that needs attention. That’s how these projects are. One thing leads to another, and then another. Lol