Two O-rings and two special washers for the hydraulic tube "standpipe", as well as one O-ring for the top cover. If you remove your tube or top-lid, consider replacing these O-rings and washers. You'll use one O-ring and washer on the top of the pipe; and the other O-ring and washer on the bottom of the tube and the final O-ring for the top cover.
Â
Â