Dave,

I am about to do your above procedure. I am replacing the o-ring as a last ditch since my vac booster is leaking.

Do I need to fill the MC and bleed the brakes to check if the new o-ring allows the booster to hold vacuum?

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car