I'm working on an 80's vintage Mitsui Seiki horizontal mill that has spindle lube issues.
It has an air powered lube pump and an air / oil mixer distribution system with a line to each bearing in the spindle.
There is a Klixon style pressure switch in the oil line that closes at about 150 psi.
The control needs to see this switch closed for about 20 seconds, but we get less than that.
Sometimes a lot less.

I'm unfamiliar with this type of system and to effectively repair it, I need to know how it works.

Can anyone here explain it to me?
Extra emphasis on the air / oil mixer.

Thanks......Rob.