Komatsu 830E-AC Shop Manual page 588

FAILURE MODES CHECK-OUT
23. Allow engine to run until low brake accumulator
pressure stabilizes at or above 22,064 kPa
(3,200 psi).
24. Shut engine down. Allow 90 seconds for the
steering accumulator to bleed completely down.
Disable steering pressure switch from the brake
warning circuit by
between circuits 33 and 33F. (This is diode 22
on diode board 1.) Turn key switch ON. After
two minutes, record the low accumulator pres-
sure (LAP1 port). If LAP1 pressure is below
17,927 kPa (2,600 psi), then leakage in the sys-
tem is excessive and the source of the leakage
needs to be identified and repaired.
· Record on data sheet.
25. Slowly open the front brake accumulator bleed
down valve and observe LAP1 pressure. The
Low Brake Pressure lamp and buzzer must
actuate at 15,859 ± 517 kPa (2300 ± 75 psi).
· Record on data sheet.
26. Brake pressures should begin to rise (Auto
Apply) when LAP1 reaches 14,479 kPa (2,100
± 100 psi). Close front brake accumulator bleed
down valve.
· Record on data sheet.
J4-8
unplugging the diode
Brake Circuit Check-Out Procedure
27. Start engine to recharge hydraulic system.
Allow engine to run until low brake accumulator
pressure stabilizes at or above 22,064 kPa
(3,200 psi).
28. Turn engine off. Allow the steering accumulator
to bleed completely down. Turn key switch ON.
Slowly open the rear brake accumulator bleed
down valve and observe LAP1 pressure.
Record LAP1 pressure at set points for low
brake warning lamp and auto apply brake pres-
sures. Also record front and rear brake pressure
after auto apply.
· Record on data sheet.
NOTE: Verify that the low brake pressure lamp and
buzzer, and auto apply set points are within a 690
kPa (100 psi) of those recorded in steps 25 and 26.
29. Close the rear brake accumulator bleed down
valve.
30. Enable the steering pressure switch by plugging
in the diode removed between circuits 33 and
33F.
31. Start the engine to recharge hydraulic system.
Allow engine to run until low brake accumulator
pressure stabilizes at or above 22,064 kPa
(3,200 psi).
32. Shut engine down. Do not allow steering accu-
mulator to bleed down. Make repeated slow,
complete brake applications with pedal until
auto apply comes on. Record the number of
brake applications prior to auto apply.
· Record on data sheet.
33. Remove all jumper wires, and gauges. This
concludes the brake check out procedure.
J04036