BOLT 2M3530 - Caterpillar

On-Highway Engines:
3126E (S/N: HEP1-UP; CKM1-UP; 9SZ1-UP)
C7 (S/N: SAP1-UP; KAL1-UP; WAX1-UP)
C7 BUS (S/N: C7T1-UP)
C7 TRUCK/BUS (S/N: YPG1-UP)
C9 (S/N: C9S1-UP; 9DG1-UP; ETK1-UP)
Description of Change: The new O-rings that are used on the injector sleeve have been improved. The O-rings are now made with a more rugged material.Adaptable To:
Illustration 1 g01437338
(1) Top O-ring (2) Bottom O-ring (3) Injector SleeveWhen the injector sleeves are replaced, also replace the O-rings. Refer to Table 1 for the proper O-ring for your engine.
Table 1
New O-rings    
Location     Part Number     Sales Model    
Top O-ring     310-7255     C7    
C9
3126
Top O-ring     310-7258     C7 with the S/N:C7S1-UP serial number prefix    
C9 with the S/N:C9S1-UP serial number prefix
Bottom O-ring     310-7257     C7    
C9
3126
Bottom O-ring     310-7259     C7 with the S/N:C7S1-UP serial number prefix    
C9 with the S/N:C9S1-UP serial number prefix Refer to your engine's Disassembly and Assembly Guide, "Unit Injector Sleeve - Install" for the proper installation procedure for the new O-rings and the new injector sleeve.