The whine is usually from sucking air into the fluid. Very few problems with that style pump when I worked at the dealer. What does the fluid resivoir look like? Is it clear or does it have small air bubbles in it? You can make up a modified cap and vacuum the system. This will draw the air out over a period of time.
Doug
I am thinking this may be part of the problem. It doesn’t look as clear as I’d like
The reservoir fluid level is also lower than the high pressure line outlet. When these pumps are setup with an AN adapter and an AN 90° fitting, that line gets pretty high relative to the proper fluid level. Perhaps that isn’t helping with aeration.
I like the idea of vacuum on the cap. I’ll need to think on a solution for that.
