Test Set Up Procedure
1. Setup valve on test stand as shown in Figure 3-12.
2. Attach the pilot input supply line to the port labeled
“PX” on the side of the valve.
3. Attach the main supply input pressure line to the
port on the front of the valve labeled “P”.
4. Attach the tank return line to the port labeled “T”.
5. Attach the regulated output ports “B1” and “B2”
to the test lines. Pressure monitoring devices in
these two lines must be capable of 3,000 psi
(20,680 kPa). Connect all ports. The connections
should be according to the diagram shown in
Figure 3-12. 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 2750 psi (18,960 kPa) at pressure gauge (3).
Pressure gauges (9 & 10) should read zero.
7. Adjust pressure regulator (4) to set pilot supply
pressure to 2400 psi (16,545 kPa) on gauge (7).
8. Return line pressure during this test is not to
exceed 0 psi (0 kPa).
9. Test the valve with ISO 32 grade hydraulic oil at
120° ±10° F (49° ±3° C).
Brake Valve Output Pressure Adjustment
1. With pump operating and supply and pilot pres-
sure adjusted as described in setup instructions,
inspect valve for leakage.
2. With 2400 psi (16,545 kPa) pilot pressure applied,
verify the following regulated output pressures:
“B1” port gauge (10) reads 2400 ±75 psi
(16,545 ±517 kPa)
“B2” port gauge (9) reads 2400 ±75 psi
(16,545 ±517 kPa)
3. Close the pilot supply needle valve (5) and open
the pilot pressure release needle valve (6) to
bleed pressure back to the reservoir.
Pilot pressure gauge (7) should drop to 0 psi
(0 kPa).
Regulated output pressure lines “B1” and
“B2” should drop to 0 psi (0 kPa) on gauges
(10) and (9) respectively.
4. Repeat steps 2 and 3 approximately 50 times to
cycle valve from minimum to maximum apply
pressure.
5. Verify output pressure remains within specifica-
tion. If not, the valve must be rebuilt.
6. While observing pilot pressure gauge (7) and
regulated output pressure gauges (9 & 10), apply
pilot pressure slowly and steadily until 2400 psi
(16,545 kPa) (maximum) pilot pressure is ob-
tained.
Pilot pressure and regulated output pressure
must track within 50 psi (345 kPa) after the
pilot pressure reaches 100 psi (690 kPa).
7. Reduce pilot pressure to 0 psi (0 kPa). Apply 2400
psi (16,545 kPa) pilot pressure as quickly as
possible.
Regulated output pressure must increase to
2400 ±75 psi (16,545 ±517 kPa) within 1.0
second after pressure is applied to pilot line.
8. Check internal valve leakage from port “T” with
full supply pressure (port “P”) applied:
With pilot pressure released, leakage must
not exceed 100 cc/minute.
With 2400 psi (16,545 kPa) pilot pressure
applied, leakage must not exceed 150
cc/minute.
9. Adjust differential pressure switch using the fol-
lowing procedure.
J3-20 Brake Circuit Component Service J03019 1/99
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