Manifold And Hydraulic Pumps; Hydraulic Brake Pressure Adjustment - Skyjack SJ40 T+ Service Manual

Manifold and Hydraulic Pumps

5.7 Manifold and Hydraulic
Pumps
5.7-1 Hydraulic Brake Pressure
Adjustment
Maintaining accurate hydraulic brake pressure is
important when it comes to safe MEWP operation.
1. Ensure the MEWP is on a firm level surface and
is in stowed position.
2. Locate the pressure gauge on the brake valve
assembly.
1
3. Remove the wiring from two valves: axle lockout
valve wires 65 and 02, and two speed valve
wires 45A and 02. Mark the valves to ensure
you put the wiring back in the correct positions
later.
CAUTION
Failure to remove the wiring may cause damage to
components downstream.
4. Locate brake system pressure reducing valve
PR1 . Loosen the lock nut and turn the
1
adjustment stem gently clockwise 2 full turns.
WARNING
Valve damage will occur if tightened too much.
WARNING
Ensure that there are no personnel or obstructions
in test area and there is sufficient room for forward
or reverse travel.
SJ40 T+, SJ45 T+
2
5. Start the engine from the platform control
console and extend the boom slightly to achieve
low speed drive.
6. Drive the MEWP forward or reverse. The
pressure gauge reading should be 550 psi. Stop
the MEWP . Follow the next steps for adjusting
the relief valve pressure if needed. If no
adjustment is required continue to step 10.
7. Locate brake pressure relief valve RV5
loosen the lock nut.
8. Turn the adjusting stem on the pressure
relief valve RV5 ¼
a time clockwise to increase pressure or
counterclockwise to decrease pressure. Drive
the MEWP forward or reverse, note pressure and
stop the MEWP .
9. Repeat step 8 until brake pressure is achieved
(550 psi) then tighten lock nut on brake system
pressure relief valve RV5
10. Locate brake system pressure reducing valve
PR1 and turn the valve gently counterclockwise
to the initial position.
11. Drive the MEWP forward or reverse. Pressure
gauge reading should be 500 psi.
12. Stop the MEWP and adjust pressure reducing
valve PR1 1/4 turn at a time by turning
1
either clockwise to increase pressure or
counterclockwise to decrease pressure.
13. Repeat step 11 and 12 until brake pressure is
achieved (500 psi) then tighten lock nut on brake
system pressure reducing valve PR1
14. Reinstall the wiring in the same positions it was
removed from in step 4.
15. Test the brake and two speed functions.
Section 5 – Procedures
and
2
of a revolution at
2
.
2
.
1
238273AAA
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