I have seen O-rings available but what about the large seal (approx 4cm)on the "plunger"/piston? Any other thoughts - my machine started dispensing coffee into the coffee grinds container rather than out the spout, when I packed out the large seal it started working again therefore I suspect this seal to be the problem! What other maintenance/service parts regularly fail and might be worth changing as it is now approx 10 years old? Many thanks for help.