Abstract: A package cartridge is provided for use in the maintenance of a packing bore for a plunger-type pump. According to one aspect, a packing cartridge includes: a generally-cylindrical sleeve adapted to be at least partially positioned in the packing bore, a first abutment ring positioned in the sleeve, and a second abutment ring positioned in the sleeve and co-axially spaced apart from the first abutment ring. Telescoping structures are operatively positioned between the first abutment ring and the second abutment ring. According to another aspect, a structure forming a circumferential pressure-ring groove is provided. A pressure ring is positioned in the pressure-ring groove, the pressure ring having at least one smaller external dimension than an internal dimension of the pressure-ring groove, whereby at least one clearance is provided between the pressure-ring groove and the pressure ring.