Komatsu 830E-AC Shop Manual page 587

BRAKE SYSTEM CHECK-OUT
NOTE: Unless otherwise specified, perform the
following checks with engine running, the directional
control lever in PARK and brake lock released.
12. VERY SLOWLY depress brake pedal to check
circuit tracking. Rear brake pressure must begin
to rise before front brake pressure. Rear brake
pressure should be between 310 - 1413 kPa
(45 - 205 psi) when front brake pressure begins
to rise. Force feedback of pedal on foot should
be smooth with no abnormal noise or mechani-
cal roughness.
· Record on data sheet.
13. Slowly depress brake pedal and check to see
that brake indicator lamp and stop lights illumi-
nate at 517 ± 34 kPa (75 ± 5 psi) rear brake
pressure.
· Record on data sheet.
14. Quickly and completely depress brake pedal
and check to see that front brake pressure is
20685 ± 1034 kPa (3000 ± 150 psi) and that
rear brake pressure is 10894 ± 517 kPa (1580 ±
75 psi) within one second of brake application.
Both brake circuit pressures must remain above
their minimum values for a minimum of 20 sec-
onds.
· Record on data sheet.
15. Release pedal, and within two seconds, assure
that each circuit's pressure is zero.
· Record on data sheet.
16. To check pedal free play, refer to the procedure
"Additional Testing and Adjustment (With brake
pedal installed)" in this Section J of the service
manual.
NOTE: Free play is defined by the gap between the
setscrew (in the pedal structure) and the actuator
cap. There must be a gap to prevent brake drag.
J04036
BRAKE LOCK
17. Disconnect wire harness from brake lock sole-
18. Apply brake lock. Brake degradation switch
19. Depress brake pedal until warning stops, then
20. Connect brake lock solenoid to wire harness.
21. Cycle brake lock several times to assure crisp
22. Apply brake lock and read brake pressures.
Brake Circuit Check-Out Procedure
noid, located on brake manifold in hydraulic
cabinet, and to the right of the PK2 port.
should activate the warning buzzer and low
brake pressure warning light.
very slowly release the brake pedal until warn-
ing resumes. Brake lock degradation switch
should sound alarm when BR pressure drops to
6895 ± 172 kPa (1000 ± 25 psi).
· Record on data sheet.
shift of solenoid valve and release of oil pres-
sure.
Front pressure should be zero and rear pres-
sure should be 10343 ± 690 kPa (1500 ± 100
psi).
· Record on data sheet.
J4-7