As I had to take out the ALDA (W124 '87 300DT) because of fixing the stop valve, I noticed that it does not hold neither vacuum nor pressure. I took it apart (four philips on the bottom) to see no rubber membranes inside (although I saw hint that once there may have been one). Am I correct assuming that both the top metal membrane and the bottom metal membrane should have a rubber membrane around them?

Thanks,

Greg

__________________
1983 560SL Megasquirted (originally 380SL)

My former Mercedes:
1985 300SD ~190k
1990 560SEL
2000 C220 CDI
1983 380SEC 102k dual-chain conversion
2000 C280 70k (sold)
1987 300DT (W124 - sold)
1972 220D (sold)
1971 220D (sold)

No. They are bare metal.

Don't worry about it not holding vacuum, it will never see vacuum in operation. The ALDA won't hold pressure when it is removed.