Oily.
DO NOT MESS WITH BRAKE CHAMBERS!! They will take your head off!! I'll find a service manual for you. Believe me, they will kill you.
John,
Firstly, let me say I appreciate you looking out for me. Fortunately, I had called a life long friend (also my dad's youngest brother) who started managing an "on road" service team about 15 years ago with about 6k trucks, now 12k+. I trust his judgement in this area and called him for different reasons re: those air brakes, but got a "talking to" right out of the gate. He had only been stern with me like that one other time, and I was young and dumb and deserved it. I was caught off guard and taken back. I later chalked it up to the seriousness of the matter.
Whatever got me to him at that moment got me there and it scared the crap out of me. I'm very much a "feet first" sorta guy and was on the heels of popping those cans when I called him. The only reason I stopped to call was to make sure I wasn't overlooking something silly before causing myself work.
I suppose all this is to the point I was originally trying to make with the statement. Being the "feet first" sorta guy with all this stuff that is new to me - I have a recognized need to slow down, educate myself through knowledge sources not getting 100% via experience as usual, and get help where needed (whether unclear, risky, or just to large to handle).
And my wife keeps worrying about me choking on the mint I have each night - let's keep it that way :)