HARNESS AS-ENGINE 2022090 - Caterpillar

Introduction
When the words "use again" are in the description, the specification given can be used to determine if a part can be used again. If the part is equal to or within the specification given, use the part again.When the word "permissible" is in the description, the specification given is the "maximum or minimum" tolerance permitted before adjustment, repair and/or new parts are needed.A comparison can be made between the measurements of a worn part and the specifications of a new part to find the amount of wear. A part that is worn can be safe to use if an estimate of the remainder of its service life is good. If a short service life is expected, replace the part.Reference: For complete Specifications with illustrations, Systems Operation and Testing and Adjusting procedures, make reference to Challenger 65B and 75 Agricultural Tractors Service Manual, SENR4960.Service Brake System and Parking Brake
Service Brake System Schematic
(1) Bleeder valve assembly. (2) Differential steer case sump. (3) Differential steer lube pump (brake boost). (4) Brake pedal. (5) Orifice connector. (6) Booster power cylinder. (7) Brake master cylinder. (8) Multiple disc inboard brake. (9) Pressure switch.The components of the service brake system are: booster power cylinder (6), brake master cylinder (7), Differential steer lube pump (brake boost) (3), brake pedal (4), and multiple disk inboard brake (8) located in the steering differential.The system has two different hydraulic circuits: a brake circuit to operate the multiple disk brake and a brake boost circuit that hydraulically assists the power cylinder to reduce brake pedal effort by the operator. The service brake system is equipped with bleeder valve assembly (1) to remove air from the system. The brake boost circuit is equipped with orificed connector (5) to allow for pump priming in the event of air trapped in the line.When the engine is running, differential steer lube pump (brake boost) (3), fastened to the charge pump, takes oil from differential steer case sump (2) and sends it to brake booster power cylinder (6). Pressure switch (9) in the brake boost circuit turns on a warning light, on the instrument panel, when the brake circuit pressure is below 35 kPa (5 psi). The light goes out when the brake circuit pressure is above 90 kPa (13 psi).When brake pedal (4) is not pushed, booster flow is unrestricted through booster power cylinder (6) and returns to the differential steering unit for lubrication purposes. As the operator pushes brake pedal (4) the booster restricts the output flow which increases the booster pressure that multiplies the force from the pedal linkage connected to booster power cylinder (6). The large and small cylinders in the two-stage master cylinder begin to send fluid to the multiple disc inboard brake (8). When the brake line pressure reaches approximately 930 kPa (135 psi), a bypass valve in the master cylinder opens. This causes the force from the booster power cylinder to work against just the small diameter cylinder. The brake line pressure can then increase to