Preventative Maitnenace:
So, before you start, pour in some nice, hot water into the sump (preferably to the top of the filter). You may wish to add some cooking oil to help with lubrication. Let it set for around 30-60minutes, or more if the machine has sat around for years without usage.
You'll then want to hook the machine up and run through a Cancel/Drain cycle on the time, to ensure the machine can push the water out. Would also recommend installing a standard drain hose rather than a ribbed one at this point if you note drainage issues.
Following that, connect the machine to a hot water supply (at least 120ºF) and run the machine on a lightest cycle (I think Fast) with a little bit of detergent for the Main-Wash to wash away the Cooking Oil and any residual dirt (if any). During this time, I would perhaps put "Saran Wrap" on the front door and trip the door interlock switch so that you can see whether the machine is getting enough water and that the Wash-Arm Support isn't worn out badly. Below are two videos another member on the forum here ("chachp") did of his KDS-21 before and after the New Wash-Arm support.
While the machine runs, check diligently for leaks from the water intake, drain, pump, door and so on.
Before:
After: