Usage:
768C (02X) Tractors;
769C (01X) Trucks;
771C (3BJ) Quarry Trucks
- SUPPLEMENT: 11/22/93
Service Magazine; October 25, 1993; Page 1; "Change In The Assembly Procedure Of The Damper In The Parking And Service Brake Group Provides Greater Reliability" for 768C (02X) Tractors, 769C (01X) Trucks and 771C (3BJ) Quarry Trucks.
The illustration on page 2 calls out a 7D7504 Separator Plate (3). The illustration does not call out the plate being described in the article. The correct illustration is shown below.
8X-9728 Parking And Service Brake Group.--------------- END SUPPLEMENT ---------------
Reference: Service Manual Module, SENR2944, Disassembly And Assembly, 768C Tractor & 769C Truck, Vehicle Systems, Page 88, "Service And Parking Brakes".
Service Manual Module, SENR5651, Disassembly And Assembly, 771C Quarry Truck, Machine Systems, Page 21, "Service And Parking Brakes".
Description of Change: A friction disc at the reaction plate end of the parking and service brake group may move off the end of the brake hub spline teeth. The friction disc then "mills" a larger relief groove creating debris in the brake cooling system.
Install the damper assembly with facing material toward the reaction plate.
Adaptable To: This change is effective with 768C (02X371) Tractor, 769C (01X6169) Truck and 771C (3BJ1) Quarry Truck. This change is adaptable to earlier machines. See illustration.
8X-9728 Parking And Service Brake Group.
Assemble 5D-6328 Damper (4) with the damper material facing 2G-5654 Reaction Plate (5). Assemble a 7D-7504 Separator Plate (3) between 2G-5593 Service Brake Piston (2) and the first 9W-7018 Friction Brake Disc (1).
NOTE: Make this change to the procedure in "Reference".