I wrote in a couple of weeks ago, about my 580K phase3 and it's badly leaking steering cylinder. I've since had it rebuilt, and it isn't leaking any longer. Prior to the rebuild, I was always constantly adding fluid. Since early summer, I noticed that the hydraulics were getting weak. I chalked this up to the leaking cylinder, since there was a number of times where I was low on fluid. I was at the point were I couldn't lift a full bucket of dirt, unless the pedal was to the floor. Now that it's repaired, it still does the same thing. Also, while it was there, they installed a new filter. My thinking, is that I need a new hydraulic pump. But, before I go and spend that kind of money, is there anything else it could be? Is it possible that the strainer in the tank could be clogged? Or maybe a faulty relief valve? All of the hydraulic functions are slow and weak. Backhoe and loader. Sorry for the long post, I'm trying not to leave anything out. Thanks. John.
Low hydraulics for sure but hitting the source is tricky. I just got my 580K and I note that it is losing hydro fluid as well so will be keen to see how your problem works out. Might be some plugs in the system where you could put in a gauge to check it, but I am just coming to grips with mine and hard to give advice.
Even tho the hydraulic filter was changed the oil flow may still be restricted if the screen on the side of the hydraulic pump wasn't cleaned. You may want take a look at it. You will also find this link to to a lot of good information about the 580K's. The link is to page 12. At the bottom of the page is the index to the entire book. ----> http://backhoedata.com/specifications/case-580k/case-580k-specs-12.php .
Turns out that the hydraulic pump was worn out. I guess after 26 years, the pump had enough.
"since there was a number of times where I was low on fluid. I was at the point were I couldn't lift a full bucket of dirt, unless the pedal was to the floor." All those times you operated the machine low of oil, likely killed the pump.