the center spray arm will not rotate in any cycle. it is not frozen, is not clogged as I have taken it off and put it back on. looking to buy a new arm (cheap enough). should I purchase any other parts? the bearing for center arm appears to be a simple washer. am I missing something here? glasses are retaining residue due to this lack of rotation. thanks
Does the upper arm rotate?
You said it is not clogged, did you check that both holes on the bottom, ends of the arm are clear of debris they are what makes it spin.
Check them when the arm is in position.
if you remove the are then junk can move but once the water pressurizes the arm it is pushed and clogs the holes.
FYI: If cleaning sumps etc. always be sure to manually add water to the unit before starting it. Running this pump when dry will burn out the seals.