I dont know. There's no air they've been bled to death and there are no micro bubbles in the reservoir.
I've heard that it's the fluid coming from the PS side and the HB side going into a T fitting before going into the reservoir. I'm hoping a new reservoir with an extra port will cure it.
It's not loud but I find it a little annoying on long trips.
Interesting. I have never seen a stock hydroboost on an 83/84 Turbo Regal. Does that stock setup use a T like we have to when fitting it to an 85+ car?
X3. T'd off of the pcv and had the same problem. Went to vac block and problem went away. I think how you tee off of the pcv (top vs side) determines how well it works.