Komatsu 830E-AC Shop Manual page 578

BRAKE MANIFOLD
Removal
If the brake manifold is leaking oil, a single O-Ring or
cartridge can be replaced while the manifold is still
located on the truck. See the DANGER warning
below.
Accumulators maintain high pressure. DO NOT
disconnect any hydraulic line or perform any ser-
vicing on any brake system component(s) until
all hydraulic pressure has been manually drained
from accumulators. Open manual drain valves
located on the brake manifold in the brake cabi-
net to drain pressurized oil. The manual bleed-
down valve for the rear accumulator is identified
as "NV1". The manual bleeddown valve for the
front accumulator is identified as "NV2".
Removal
1. Securely block the wheels to prevent possible
roll-away.
2. Turn key switch OFF and allow 90 seconds for
steering system accumulators to bleed down.
3. Bleed down brake accumulators by rotating the
manual bleeddown valves NV1 (13, Figure 3-
24) and NV2 (11) counterclockwise.
4. Confirm brake accumulators are bled down by
applying the Brake Lock switch (key switch ON,
engine shut down) and applying service brake
pedal. The service brake light should not come
on.
5. Close the bleeddown valves by rotating clock-
wise.
6. Remove the valve guard and Dyna-seal from
top of accumulators.
7. Depress valve core to release gas precharge
pressure from accumulators.
8. If a brake manifold cartridge is faulty or leaking
oil externally, remove the cartridge. Inspect O-
ring and O-ring seat in the manifold. Replace O-
ring or defective part(s).
J3-24
FIGURE 3-24. ACCUMULATORS AND BRAKE
1. Rear Brake Accumulator
2. Charging Valve
3. Front Brake Accumulator
4. Charging Valve
5. Brake Lock Shuttle Valve
6. Brake Lock Pressure Reducing Valve (PR1)
7. Check Valve (CV3)
8. Brake Lock Solenoid
9. Park Brake Solenoid
10. Park Brake Test Port
11. Bleed Down Valve (Front Brake Accumulator)
12. Automatic Apply Valve
13. Bleed Down Valve (Rear Brake Accumulator)
14. Accumulator Test Port (LAP1)
15. Brake Manifold
16. Low Brake Accumulator Pressure Switch
17. Park Brake Pressure Switch
Brake Circuit Component Service
MANIFOLD
J03034