1999/07/05 Caterpillar

Refrigerant Compressor Group Improvements Increase Belt Life and Reduce Guard Cracking {1802,1807}

Usage:

777B (4YC, 3NF),
777C (4XJ, 8JL),
777D (3PR, 2YW),
785 (8GB),
785B (6HK),
785C (1HW, 5AZ),
789 (9ZC),
789B (7EK),
789C (2BW),
793 (3SJ),
793B (1HL),
793C (4AR, 4GZ) Off-Highway Trucks;
776B (6JC),
776C (2TK),
776D (5ER),
784B (5RK),
784C (2PZ) Off-Highway Tractors;
994 (9YF),
994D (3TZ) Wheel Loaders

Description of Change: Many component changes have been made to the refrigerant compressor groups on the 3500 and 3500B Engines in these machines. These changes include:

* New lower pulley has a better fit with the belt

* New rubber spacer added to isolate vibration and increase belt guard life.

* New hardware to lower vibration for increased compressor life

These changes will result in increased refrigerant compressor drive belt service life and increased belt guard service life.

Adaptable To: Chart A identifies which refrigerant compressor groups go with which machines. Chart B identifies the effectivity of the improved refrigerant compressor groups with new engines. Chart C identifies the effectivity of the improved refrigerant compressor groups with remanufactured engines.

Illustrations 1 through 5 and Chart D identify the new components in the 2W-0216 and 123-6863 Refrigerant Compressor Groups.

Illustration 1.
(FRONT VIEW) Identification of new components in the 2W-0216 and 123-6863 Refrigerant Compressor Groups.

103-0880 Pulley Assembly (V).

NOTE: Before adjusting the belt tension, it is very important that the 103-0880 Pulley Assembly (V) is in the full up position and secure. Adjust the belt tension using the 147-0782 Pulley Assembly (9) and 4N-4942 Rod Assembly (6) according to the Belt Tension Chart found in the applicable System Operation, Test and Adjusting module. See Illustration 1.

Illustration 2.
(LEFT SIDE VIEW) Identification of new components in the 2W-0216 and 123-6863 Refrigerant Compressor Groups.

Illustration 3.
(VIEW A-A) Identification of new components in the 2W-0216 and 123-6863 Refrigerant Compressor Groups.

Illustration 4.
(VIEW B-B) Identification of new components in the 2W-0216 and 123-6863 Refrigerant Compressor Groups.

Illustration 5.
(SECTION C-C)

Plate Assembly (W).

Rubber Spacer (X).

Spacer (Y).

Guard Assembly (Z).

NOTE: Be sure the 172-0197 Spacer is used. This spacer provides adequate compression on the rubber spacer to remove resonance conditions.

Illustrations 6 through 10 and Chart E identify the new components in the 1W-8703 and 129-9491 Refrigerant Compressor Groups.

Illustration 6.
(FRONT VIEW) Identification of new components in the 1W-8703 and 129-9491 Refrigerant Compressor Groups.

103-0880 Pulley Assembly (V).

NOTE: Before adjusting the belt tension, it is very important that the 103-0880 Pulley Assembly (V) is in the full up position and secure. Adjust the belt tension using the 147-0782 Pulley Assembly (34) and 4N-4942 Rod Assembly (33) according to the Belt Tension Chart found in the applicable System Operation, Test and Adjusting module. See Illustration 2.

Illustration 7.
(LEFT SIDE VIEW) Identification of new components in the 1W-8703 and 129-9491 Refrigerant Compressor Groups.