OK. I have studied the schematics and manual on the 9 1/2 inch Hydrovac. I have a basic understanding how it works.
I am definitely holding atmospheric pressure, with the engine running.
It looks like they call it the control valve, just behind the inlet tube for fresh air.
So have we determined it's inside the hydro and not my MC?
If so, I don't want to go into the hydro. It is new (not a rebuilt one). I think I should get with the place I bought it.
There is a lube plug on the front of it. Maybe they did not put any lube in it? I have not took the plug out yet to check.
Don, I cannot find a vent listed in the breakdown of the parts in the manual.
Last edited by Old GMC Gold; 10/12/2014 3:16 PM.
