Well, I agree that removal is tricky as you noted. That one nut is awkward !

What matters is how good the diaphram is inside rather than the external appearance.

Try not to overextend that diaphram (stepping on brake pedal all the way to the floor when bleeding).

If you already reinstalled it, then all that is left is to see what happens !

here is a link to same topic, different car...


How did brake fluid get inside my brake booster? - Alfa Romeo Bulletin Board & Forums

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD