This pump contains 3 pistons, for service and replacement of all three pistons seals you need 3 of these kits
Technical information
Contains:
1x part 90.2848.00; position 32
1x part 90.3903.00; position 47
1x part 76.0802.70; position 48
1x part 90.2850.00; position 49
1x part 76.1002.51; position 50
1x part 76.2170.70; position 51
3x part 90.2855.00; position 60