TRANSMISSION ARRANGEMENT 9G6778 - Caterpillar

Torque is based on the diameter of the thread. The torque values are identical for coarse threads and fine threads.Note: The following table has the recommended standard torque value for tapered pipe thread fitting for use on all Caterpillar equipment and Mitsubishi engines. Use Table 1 as a general recommendation only. Actual values may vary due to variations in the material of the connector. Actual values may vary due to variations in the characteristics of the threads.
Table 1
Tapered Pipe Thread Fittings
Diameter of the Pipe Thread (Inch) Standard Torque
Assembly Turns after Hand Tight Torque
1/16 2 10 2 N m (89 18 lb in)
1/8 2 17 3 N m (150 27 lb in)
1/4 2 25 4 N m (221 35 lb in)
3/8 2 40 6 N m (30 4 lb ft)
1/2 2 55 8 N m (41 6 lb ft)
3/4 2 70 11 N m (52 8 lb ft)
1 1 1/2 100 15 N m (74 11 lb ft)
1 1/4 1 1/2 110 17 N m (81 13 lb ft)
1 1/2 1 1/2 120 18 N m (89 13 lb ft)
2 1 1/2 160 24 N m (118 18 lb ft) Note: Use 50 percent of the torque values from Table 1 when fitting, plug, or the port material is nonferrous.
Illustration 1 g06015417
Table 2
Grease Fittings (Zerk Fittings)
Diameter of the Pipe Thread (Inch) Assembly Turns after Hand Tight Torque
1/8–27 PTF Special Short Torque Values Specified in Table 1
1/8–27 NPTF
1/4–28 SAE-LT 8.5 1 N m (75.23 8.85 lb in) 6 N m (53.11 lb in) Note: Torque values listed above are recommended when assembling a steel fitting to a steel port. Other materials require additional validation.
Torque values for tapered external pipe threads (e.g., NPT, NPTF, BSPT) mated with NPSF or BSPP straight internal pipe threads shall use 50% of the value and tolerance shown in Table 1. Values for NPSM connections are shown in Table 1.Note: “Turns After Hand Tight” method shall not be used for straight internal pipe threads.
Apply thread sealant to male tapered pipe threads, unless one of the following conditions exists:
Connector is a lubrication (grease) connector.
Connector is used in non water-cooled exhaust-related engine parts.
On pipe threads which have pre-applied sealants.Connector is mated with an NPSM swivel nut.
Hand-tighten swivel nut/connector to connector/port.
Apply assembly torque by using the "Assembly Turns after Hand Tight" values or the "Dynamic Assembly Torque" values from Table 1.
One clockwise rotation past the "Maximum Assembly Torque" is allowed for orientation.