(quoted from post at 17:22:38 01/23/13)
(quoted from post at 04:45:04 01/23/13) That number sounds to me like an air filter.
The 12" paper filter is 86546604 and comes with the base gasket. The 9" composite filter is 290417 and the 290397 gasket is sold separately. The paper filter is probably what you have. 730 system capacity is listed @ 10.5 gallons, but unless you purge all the cylinders you won't need much more than 5 or 6. Full level is 12" below the fill/breather cap.
I know that three and a half years have passed since you all had the above exchange about hydraulic filters in a Ford 730 loader. Today my local NH dealer told me that he might be able to get the composite filter, 290417, for me for $107 - but he wasn't certain it was still available. PartsSpring and Messick's both list it as discontinued/unavailable - so I cleaned mine as well as I could with some kerosine and put it back into service with new hydraulic oil. Clearly, this is a short-term play. If the composite filters are now unavailable, I need to convert to another filter type.
One option is to buy the parts to convert to the paper filter 86546604, but if I could get them I would pay at least $170 (from Messick's, if they have all the parts). Another option is to discard the original filter, and plumb a spin-off filter between the sump and the pump, maybe hanging it off a bracket that I could weld onto the left loader post. Has anyone done the latter? Can anyone offer advice about doing this? I worry that I would have to put the filter up high to prevent it from getting knocked when moving over debris or rough ground, but too high and the pump might be hard-pressed to pull enough fluid up to it from the sump?