Komatsu 830E Shop Manual page 353

Test Set Up Procedure
1. Position the valve in the fixture to allow plungers
to be activated by hand using a lever (refer to
Figure 3-10).
2. Attach the pilot input supply pressure to the pilot
port labeled "PX" on the rear of the valve.
3. Attach the main supply input pressure to the
O-ring ports on the rear of the valve labeled "P1"
and "P2".
4. Attach the tank return line to the O-ring port
labeled "T" on the rear of the valve.
5. Attach the O-ring regulated output ports "B1" and
"B2" to the test lines. Pressure monitoring de-
vices in these two lines must be capable of 3,500
psi (24 132 kPa). Connect all ports. The connec-
tions should be according to the diagram shown
in Figure 3-10. All ports must be used and con-
nected.
All ports must be used. Relieve pressure before
disconnecting hydraulic and other lines. Tighten
all connections before applying pressure.
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.
6. Start hydraulic pump and regulate output pressure
to 3200 psi (22 064 kPa) at pressure gauge (3).
Pressure gauges (7 & 10) should read zero.
7. Set pilot supply pressure on test stand to 3200 psi
(22 064 kPa).
8. Return line pressure during this test is not to
exceed 5 psi (34 kPa).
9. Test the valve with ISO grade hydraulic oil at 120°
±10° F (49° ±3° C).
Brake Valve Output Pressure Adjustment
1. Install the pedal pivot shaft pin in the actuator base
by itself without installing the pedal assembly.
2. By taking a screw driver or pry bar and placing it
under the pivot pin and on top of the threaded
plunger assembly, each circuit can be actuated
individually. Refer to Figure 3-10.
J03022 1/99
3. Gradually apply pressure on each circuit (one at
a time) to check for leaks around the plunger.
Make sure the adjustment collar is screwed all the
way down on the threads.
4. "B1" Adjustment: Adjust the adjustment collar
up (counter-clockwise) starting with one turn in-
crements until the output pressure at port "B1" is
2000 -0/+75 psi (13 790 -0/+517 kPa) with the
adjustment collar contacting the actuator base
(fully actuated). Fine adjustment will require
turning the collar only in 1/8 turn increments.
5. "B2" Adjustment: Adjust the adjustment collar
up (counter-clockwise) starting with one turn in-
crements until the output pressure at port "B2" is
3000 -0/+150 psi (20 685 -0/+1 034 kPa) with the
adjustment collar contacting the actuator base
(fully actuated). Fine adjustment will require
turning the collar only in 1/8 turn increments.
6. Tighten the setscrews in the adjustment collars to
25 - 30 in.lbs. (2.8 - 3.4 N.m) torque. The entire
plunger may have to be rotated to get to the
capscrews.
7. Check pressures again after tightening the set
screws. If the pressures have moved out of speci-
fied range, loosen the appropriate set screw and
re-adjust.
8. Cycle each circuit 50 times using pilot apply. This
is done by closing needle valve (5) and opening
needle valve (4). Read pressure on gauges (7 &
10). Close valve (4) and open valve (5). The
pressure gauges (7 & 10) should read 0 psi.
9. Recheck pressures after cycling. If they have
changed, re-adjust pressures.
Differential Pressure Switch Test
10. Attach ohmmeter lead to connector on differential
pressure switch wire. Attach other lead to valve
body.
11. Insert pry bar under pivot pin to actuate the "B1"
section of valve.
12. Slowly depress plunger while observing the ohm-
meter; switch contacts should close at pressure
shown in Table I.
Table I - Differential Pressure Switch Adjustment
Spring
Color
Red
Green
Brake Circuit Component Service
Pressure - Switch Contacts Closing
"B1" Valve Spool "B2" Valve Spool
250 ±30 psi 375 ±50 psi
(1 724 ±207 kPa) (2 585 ±345 kPa)
600 ±50 psi 1000 ±75 psi
(4 137 ±345 kPa) (6 895 ±517 kPa)
J3-11