LT Don reassured me: "If you can tug on the valve and feel resistance when it is being held on only by the MityVac, you're good to go."
So...help me review...There are only two places oil can get into the vacuum system: the vacuum pump and the shut off valve, correct?
If I put the Mity Vac on the currently installed shut off valve, its hold vacuum all day long...now I'm kinda stumped.
Bob Rentfro '77 300D 142K Litchfield Park, AZ
