Case Drain Filter Questions - Bobcat - Any experience with this?

This Bobcat S300 has two case drain filters - one under the cab and one behind the rear left side access panel behind the tire. The one behind the tire is easy to get at and only has one hose going into each end of the filter. That should be easy to take apart and to remove the cartridge. But the one under the cab looks a lot tougher - it has a maze of hoses attached to both ends of the filter case and is jammed in under other stuff.



Any tips for changing these filters?



Is is necessary to drain the hydraulic oil tank and system first to avoid having five or ten gallons of oil leak out of the hoses after disconnecting them? Also, can one just clean the filters, or is it necessary to replace them?



Thanks for any help.