The lower and upper o-rings and o-ring carriers for the mounting post and piston-cylinder assembly are the same size and general shape. It is very important that they are in the correct positions (upper or lower) and orientation.
Upper o-ring is orange silicone
Part number: 3142761
Description: 103621,O-RING,SILICONE,2-128
Upper o-ring carrier
Part number: 3147530
Description: 123091,CARRIER,ORING,TOP,FPG CYL
Lower o-ring is Brown Viton
Part number: 3143241
Description: 103692, O-RING, VITON, BRN, 2-128
Lower o-ring carrier
Part number: 3147137
Description: 122930, CARRIER, ORING,BTM, FPG CYL
Kit
Part Number: 3127278
Description: 402293, KIT, CARRIERS/O-RINGS, FPG
Includes these parts
PN Qty Description
3142761 1 103621, O-RING, SILICONE, 2-128
3143241 1 103692, O-RING, VITON, BRN, 2-128
3147137 1 122930, CARRIER, ORING, BTM, FPG CYL
3147530 1 123091, CARRIER, ORING, TOP, FPG CYL
Same info above is in attached file below.
The o-ring that seals the upper and lower mounting post is here,
Part Number: 3139134
Description: Silicon (orange), 2-151; Parker 2-151-S0899-50
Parts can be quoted or ordered from orders@flukecal.com or by calling 877-355-3225. Contact Pressure Technical Support at the same phone number or at the link below.