my new jabsco aqua filta 59000 is leaking through the top of the caseing

[old porkchops]

i have a jabsco par-max 2-+ drinking water pump fitted with a jabsco aqua filta 59000 water filter i replaced the cartridge this year and now the filta unit has starded leaking through the top of the unit . I thought the unit had cracked so i bought a new filter and that one leaks as well also at this time the pump has started to play up it wont shut down when the tap is turned off
ANY IDEA WHAT THE TROUBLE IS AND HOW TO FIX IT PLEASE