Series 1 - T-21A cavity, buna-N, cartridge seal kit

Sun offers replacement seal kits for all cartridge models. These kits include all of the external seals on the cartridge along with installation instructions. Seal kits are available in Buna-N and Viton for all models, along with EPDM and polyurethane for many models. Please note: Converting the external seals from one material to another does not ensure fluid compatibility with that material due to the existence of internal seals within the cartridge.

• The shelf life for this cartridge seal kit is ten years from date of purchase. This date will be printed on the kit packaging.

What models can this kit be used with?

• CVCV Vented pilot-to-open check valve
• CWCA 3:1 pilot ratio, vented counterbalance valve
• CWCG 5:1 pilot ratio, vented counterbalance valve
• CWCK 1:1 pilot ratio, vented counterbalance valve
• CWCL 2:1 pilot ratio, vented counterbalance valve
• DKDP Normally closed, balanced poppet, logic element - pressure adjustable
• DKDR Normally closed, balanced poppet, logic element - vent-to-open
• DKDR8 Normally closed, balanced poppet, logic element with integral T-8A control cavity - vent-to-open
• DKDS Normally closed, balanced poppet, logic element - pilot-to-open
• DODP Normally open, balanced poppet, logic element - pressure adjustable
• DODR Normally open, balanced poppet, logic element - vent-to-close
• DODR8 Normally open, balanced poppet, logic element with integral T-8A control cavity - vent-to-close
• DODS Normally open, balanced poppet, logic element - pilot-to-close
• DPBM 2-way, pilot-operated, directional valve with drain to port 4 - normally open
• DPBN 2-way, pilot-operated, directional valve with drain to port 4 - normally closed
• DPBO 3-way, pilot-operated, directional valve with drain to port 4 (1 blocked, 2 to 3 open)
• DPBP 3-way, pilot-operated, directional valve with drain to port 4 (1 to 2 open, 3 blocked)
• DRAX 2-way, pilot-to-shift directional valve with drain to port 4 - normally closed
• DRAY 2-way, pilot-to-shift directional valve with drain to port 4 - normally open
• DRBM 2-way, direct-acting, directional valve with drain to port 4 - normally open
• DRBMX 2-way, direct-acting, fixed setting, directional valve with drain to port 4 - normally open
• DRBN 3-way, direct-acting, directional valve with drain to port 4 - normally closed
• DRBNX 2-way, direct-acting, fixed setting, directional valve with drain to port 4 - normally closed
• DRBO 3-way, direct-acting, directional valve with drain to port 4 (1 blocked, 2 to 3 open)
• DRBOX 3-way, direct-acting, fixed setting, directional valve with drain to port 4 (1 blocked, 2 to 3 open)
• DRBP 3-way, direct-acting, directional valve with drain to port 4 (1 to 2 open, 3 blocked)
• DRBPX 3-way, direct-acting, fixed setting, directional valve with drain to port 4 (1 to 2 open, 3 blocked)
• DRBR 3-way, direct-acting, directional valve with drain to port 4 (3 to 4 open, port 2 blocked)
• DRBRX 3-way, direct-acting, fixed setting, directional valve with drain to port 4 (3 to 4 open, port 2 blocked)
• DVBM 2-way, vent-to-operate, directional valve with drain to port 4 and integral T-8A control cavity - normally open
• DVBN 2-way, vent-to-operate, directional valve with drain to port 4 and integral T-8A control cavity - normally closed
• DVBO 3-way, vent-to-operate, directional valve with drain to port 4 and integral T-8A control cavity (1 blocked, 2 to 3 open)
• DVBP 3-way, vent-to-operate, directional valve with drain to port 4 and integral T-8A control cavity (1 to 2 open, 3 blocked)
• FKBA 2-way, pilot-shifted, proportional throttle
• FKBB 2-way, pilot-shifted, proportional throttle with bleed down
• FKCA 2-way, pilot-shifted, proportional throttle, high capacity
• FKCB 2-way, pilot-shifted, proportional throttle with bleed down, high capacity
• FVCA Ventable, fixed-orifice, bypass/restrictive, priority flow control valve
• FVCA8 Ventable, fixed-orifice, bypass/restrictive, priority flow control valve with integral T-8A control cavity
• HVCA Ventable, pilot-operated, balanced piston relief valve - before check
• HVCA8 Ventable, pilot-operated, balanced piston relief main stage with integral T-8A control cavity - before check
• LPDS Normally open modulating element with shuttle
• LRDS Normally closed modulating element with shuttle
• PSDB Direct-acting, pressure reducing/relieving valve with drain to port 4
• PSDL Electro-proportional, direct-acting, pressure reducing/relieving valve with open transition and drain to port 4
• PSDP Electro-proportional, direct-acting, pressure reducing/relieving valve with drain to port 4
• PSDT Direct-acting, pressure reducing/relieving main stage piloted from port 4
• PVDA Pilot-operated, pressure reducing/relieving valve with drain to port 4
• PVDA8 Pilot-operated, pressure reducing/relieving main stage with integral T-8A control cavity and drain to port 4
• PVDB Ventable, pilot-operated, pressure reducing/relieving valve
• PVDD Ventable, pilot-operated, pressure reducing/relieving valve with drilled piston orifice
• QCDA 15%, accumulator sense, pump unload valve with check - pilot capacity
• QCDB 20%, accumulator sense, pump unload valve with check - pilot capacity
• QCDC 30%, accumulator sense, pump unload valve with check - pilot capacity
• QCDD 50%, accumulator sense, pump unload valve with check - pilot capacity
• RVCD Ventable, pilot-operated, balanced piston relief valve with drain to port 4
• RVCD8 Ventable, pilot-operated, balanced piston relief main stage with integral T-8A control cavity and drain to port 4
• XMBA Port 1 to 3 open, ports 2 and 4 blocked, cavity plug
• XMCA All ports blocked cavity plug
• XMOA Ports 3 and 4 or port 5 and 6 blocked, all other ports open cavity plug
• XMOB All ports open cavity plug

• Install back-up rings and O-rings as shown in views.
• See installation variations for models associated with alternative installation views.
• When installing continuous back-up rings, use the same technique and the same care used to install O-rings.
• When installing cartridge - be sure to torque to recommended value.

• Seals: Materials of Construction
• Seal Kit Installation Guidelines
• Sun's Floating Style Screw-In Cartridge (1.06 MB)