The old check valve:
Missing tube and "glued-on" hose:
Old and new:
Rubber grommet: Spot the difference in diameter between new and old!
Final assembly: Another problem solved!
Final remark: After I ordered the valve from Porsche, I found out that the same part number (477 611 933 A) can be purchased from Volkswagen Classic Parts for half the price!
Porsche: 36,39 €
VW Classic : 18,96 €