Tempermental Hydraulics

[beaverplt]

Hi all, First post on this site even though I've owned my Kubota for over 20 years.
I have an L225 Kubota with a Johnson WorkHorse front end loader. My problem is the hydraulics will, on occasion, stop working. It is not just the hydraulics to the loader as the three point hitch won't work either. If I can leave it for a couple hours or a day and it usually will start working again. I'm mechanically inclined, but not very knowledgable on hydraulics. Can anyone point me in the right direction to look for issues? Thanks

 

[cviola2005]

Start with changing the fluid and filter.

 

[North Idaho Wolfman]

Check for a suction leak.

 

[beaverplt]

Well, don't I feel stupid. I only know about the fuel, oil, and air filters. I looked up the hydraulic filter and discovered it's internal. The posts I saw talked about cleaning it. I'm guessing that since I've never done that, I should probably just put in a new one.
Where would I look for a suction leak, the hoses, cylinders, both? Would a suction leak also leak fluid out when the hydraulics are not engaged?
Also, the hydraulics have not worked at all since Tuesday. Should I be concerned about the hydraulic pump?

Thanks so much for the help.