Parking Brake - Komatsu 830E Shop Manual

INITIAL SYSTEM SET-UP
Prior to checking the brake system, the hydraulic
steering system must have proper accumulator pre-
charge and be up to normal operating temperatures.
Refer to Section "L" this manual for steering system
operation procedures and specifications. Also prior to
checking the brake system make sure the parking
brake is properly adjusted. Refer to parking brake
adjustment this section. With the steering system
functioning properly and the parking brake adjusted,
proceed as follows:
1. Turn engine and key switch off.
2. Fully open each brake accumulator bleeddown
valve and precharge both accumulators to 1400
psi (9650 kPa). Allow gas temperature to
approach ambient temperature before complet-
ing precharge process.
· Record on data sheet.
NOTE: For best performance, charge accumulators
in the ambient conditions in which the machine will
be operating.
3. Close both accumulator bleeddown valves.
4. Install pressure gauges at:
a. Front Brake Test Port "BF" (brake cabinet) -
5000 psi (34,475 kPa) gauge.
b. Rear Brake Test Port "BR" (brake cabinet) -
5000 psi (34,475 kPa) gauge.
c. Low Accumulator Pressure Test Port "LAP1"
(brake manifold) - 5000 psi (34,475 kPa)
gauge.
5. Set park brake. Release brake lock.
6. Start engine. Observe rising brake pressures as
system charges. Brake pressure should begin
to fall when Auto Apply Valve releases. Brakes
should release at approximately 2000 psi
(13,790 kPa).
· Record on data sheet.
7. Partially depress brake pedal and bleed air from
bleeders located at each brake.
J4-4

PARKING BRAKE

NOTE: Move one of the pressure measuring
instruments from the BF or BR locations to the PK2
test port above the Park Brake Solenoid.
8. Actuate brake lock. Release parking brake with
9. Measure the lining to disc clearance with feeler
10. Apply parking brake and release brake lock.
NOTE: Return the pressure gauge to the BF or BR
location from which it was removed.
BRAKE SYSTEM CHECK-OUT
NOTE: Unless otherwise specified, perform the
following checks with engine running, park brake set
and brake lock released.
11. VERY SLOWLY depress brake pedal to check
12. Slowly depress brake pedal and check to see
13. Quickly and completely depress pedal and
Brake Circuit Check-Out Procedure
park brake switch. Verify that Park Brake Status
Light indicates parking brake is released. Park
Brake pressure should be 2500 ± 100 psi
(17,238 ± 690 kPa).
· Record on data sheet.
gauge and record the clearances.
· Record on data sheet.
circuit tracking. Rear brake pressure must begin
to rise before front brake pressure. Rear brake
pressure should be between 45 psi (310 kPa)
and 205 psi (1413 kPa) when front brake pres-
sure begins to rise. Force feedback of pedal on
foot should be smooth with no abnormal noise
or mechanical roughness.
· Record on data sheet.
that brake indicator lamp and stop lights illumi-
nate at 75 ± 5 psi (517 ± 34 kPa) rear brake
pressure.
· Record on data sheet.
check to see that front brake pressure reads
3000 ± 150 psi (20685 ± 1034 kPa) and that
rear brake pressure reads 1980 ± 100 psi
(13650 ± 689 kPa) within one second of brake
application and that both pressures remain
above their minimum values for a minimum of
20 seconds.
· Record on data sheet.
J04031