George Murphy sells replacement diaphragms. I don't know if they fit that particular module. Search on his name on the forum and his phone number will come up. He doesn't have a website. He could tell you if the diaphragms fit. They are not expensive.
I'd be inclined to use a small glob of Goop to repair the existing one, rather than a tube repair kit.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13