Caterpillar 121-0145 O-Ring Seal – 28.17mm ID – Genuine Cat Replacement

The Caterpillar 121-0145 O-Ring Seal is a heavy-duty sealing component designed for use in Caterpillar engines and equipment. This O-ring provides reliable sealing in static and selected dynamic applications, helping prevent fluid leakage and contamination.

Manufactured to Caterpillar specifications, the 121-0145 features a 28.17 mm (1.109") inside diameter and 0.139" cross-section diameter. The seal material is HNBR and is designed to provide resistance to wear, extrusion, petroleum oils, diesel fuels, coolants, ozone, and other fluids commonly encountered in heavy-duty equipment.

Part Number: 121-0145 / 1210145
Brand: Caterpillar
Part Type: O-Ring / Seal
Inside Diameter: 28.17 mm (1.109")
Cross Section: 3.53 mm (0.139")
Material: HNBR
Hardness: 78A
Dash Size: 216

Applications

Caterpillar lists the 121-0145 for a wide range of equipment and engines, including:

• Caterpillar 3406B, 3406C, 3406E
• Caterpillar C-15 / C15
• Caterpillar C-16
• Caterpillar C-18
• Caterpillar C-9
• Caterpillar 3306B
• Caterpillar 330B excavators
• Caterpillar 966, 972, 980 and 988 wheel loaders
• Caterpillar 770 and 770G trucks
• Caterpillar 740/740B articulated trucks
• Caterpillar 824, 825 and 826 equipment
• Caterpillar D6, D7, D8, D9 and D10 track-type tractors
• Numerous other Cat construction, mining, industrial and engine applications

Always verify the part number and equipment configuration before ordering.

Cross-Reference / Interchange

Known aftermarket references include:

• Interstate-McBee M-1210145
• PAI 131360