Komatsu 830E-AC Shop Manual page 583

BRAKE CIRCUIT CHECK-OUT PROCEDURE
The brake circuit hydraulic pressure is supplied from
the steering circuit at the bleed down manifold. Some
brake system problems, such as spongy brakes,
slow brake release, or abnormal operation of the
overhead panel mounted "Low Brake Pressure"
warning light can sometimes be traced to internal
leakage of brake components. If internal leakage is
suspected, refer to Brake Circuit Component Leak-
age Test.
1. Rear Brake Accumulator
2. Charging Valve
3. Front Brake Accumulator
4. Park Brake Pressure Reducer
Valve
5. Hoist Pilot Valve
6. Hoist Pilot Manifold
7. Hoist-Up Limit Solenoid
8. Pilot Operated Check Valve
9. Brake Lock Low Pressure Switch
10. Junction Block
J04036
FIGURE 3-1. HYDRAULIC BRAKE CABINET
11. BF & BR Test Port
(Front & Rear Brake)
12. Stop Light Switch
13. Brake Lock Shuttle Valve
14. Brake Lock Pressure
Reducing Valve
15. Brake Lock Solenoid
16. Park Brake Solenoid
17. Bleed Down Valve
(Front Brake Accumulator)
18. Accumulator Test Port
19. Automatic Apply Valve
Brake Circuit Check-Out Procedure
NOTE: If internal leakage within the steering circuit is
excessive, this also may contribute to problems
within the brake circuit. Be certain that steering circuit
leakage is not excessive before troubleshooting
brake circuit. For Steering Circuit Test Procedure,
refer to Section "L", Hydraulic System.
20. Bleed Down Valve
(Rear Brake Accumulator)
21. Brake Manifold
22. Low Brake Accumulator
Pressure Switch
23. Park Brake Pressure Switch
24. Brake Warning Delay Timer
25. Brake Warning Light Relay
26. Park Brake Test Port
27. Pressure Sensor (VHMS)
J4-3