Installation Of Brake Pedal Actuator To Brake Valve - Komatsu 830E Shop Manual

13. Insert pry bar under pivot pin to actuate the "B2"
section of valve.
14. Slowly depress the plunger while observing the
ohmmeter; switch contacts should close at the
pressure shown in Table I, "Differential Pressure
Switch Test".
15. Shut down the test bench and relieve all hydraulic
pressure from the lines.
Avoid spillage and contamination! Avoid contact
with hot oil if the machine has been operating. The
oil will be at very high pressure.
Hydraulic fluid escaping under pressure can have
sufficient force to enter a person's body by pene-
trating the skin and cause serious injury and pos-
sibly death if proper medical treatment by a
physician familiar with this injury is not received
immediately.
16. Remove hoses from valve and remove valve from
test stand. Refer to instructions below for pedal
actuator installation prior to final test.
Final Test and Adjustment
The brake pedal actuator must be installed on the
brake valve body prior to final test and adjustment.
Refer to "Installation of Brake Pedal actuator to Brake
Valve"
NOTE: The "Final Test and Adjustment" procedure
can also be performed with the brake valve installed in
the truck. To perform final test with brake valve
mounted in the truck, install valve per instructions in
"Installation". Install 3500 psi (24 132 kPa) gauges at
the BF and BR diagnostic test connectors in the brake
cabinet. Follow steps 18. - 29 below for final test.
17. Reinstall brake valve (with actuator pedal at-
tached) on the test stand following steps 2 through
9. under "Test Setup Procedure".
18. With test stand pump adjusted for 3200 psi
(22 064 kPa) or with engine running and brake
system supply pressure at or above 3000 psi (20
685 kPa), depress the pedal as quickly as possi-
ble. The pressure on the output circuits must reach
the minimum pressure listed below at port "B1"
and port "B2" within 1.0 seconds. Measurement of
time begins the moment force is applied to move
the pedal.
J3-12
19. With "B1" and "B2" plugged into a strip chart
recorder, (if available) check the modulation by
slowly applying pressure until the maximum pres-
sure is reached. Make sure the pressure increase
is smooth and no sticking of the spools is ob-
served. Fully depress the pedal. Pressures must
remain within specification at "B1" and "B2" for 20
seconds.
20. Turn set screw (10, Figure 3-11) out (counter-
clockwise) so that set screw is not touching the
actuator cap. Apply Locktite
ment screw prior to setting the deadband.
21. Set the deadband by placing a 0.025 in (0.635 mm)
thick shim at location (11) between the pedal
structure and return stop boss on pivot structure.
22. Turn the set screw (10) in (clock-wise) just until the
set screw is touching the cap.
23. Continue turning the set screw clock-wise until
pressure begins to rise on one of the brake apply
pressure gauges.
24. Back-off the set screw 1/8 turn (counter-clock-
wise).
25. Tighten the jam nut (9) and remove the shim stock
inserted in step 21.
26. Fully stroke the brake pedal actuator to check that
output pressure at port "B1" and "B2" are within
specifications.
NOTE: If pedal is adjusted properly, the spring and
spring pivots will not interfere with pedal travel.
27. If pressure is not within specifications, re-adjust. If
pressure is within specifications, apply a few drops
of Locktite to the jam nut.
28. Check internal leakage at port "T". Leakage must
be less than 100 cc/minute with the valve in the
released position and system pressure supplied
to the "P1" and "P2" inlet ports.
29. "T" port leakage must be less than 250 cc/minute
with valve pilot pressure or manual applied.
Brake Circuit Component Service
Rear Brake - "B1" ("BR" on truck): 2000 ±80
psi (13 790 ±552 kPa)
Front Brake - "B2" ("BF" on truck): 3000 ±150
psi (20 685 ±1034 kPa)
®
242 to the adjust-
J03022 1/99