(1) If the pump is not leaking, I doubt you require a piston kit.
(2) If the bearing is in good condition, re-grease it using a silicone grease.
(3) You probably require a Valve Kit.
I must admit, that those machines have probably serviced you very well. How old would you suspect they are and when was the last time you serviced the pumps?
Hope this helps
The JAGUAR MX-2 ETM @ cross-american.com