Anyone have any experience rebuilding the seats on a Mercedes van? The seat in my 409d has a rip and I'd like to fix it. The fabric goes over a round tube at the base of the seat then there is a half round metal clip (about 20 of them) that goes over the fabric clamping it to the round tube. Anybody seen these before? How do they come off and on?

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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