Skyjack SJ4732 - Hydraulic System; Platform Does Not Lift

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SJ3220, SJ3226, SJ4720, SJ4726, SJ4732 223198ABA
Hydraulic System Section 4 – Troubleshooting Information
4.3 Hydraulic System
4.3-1 All Functions Inoperative
1. Electric Motor DCM1 not engaged. Refer to electrical troubleshooting.
2. Pump P1 defective.
Check system pressures and Pump P1
functionality. Replace if defective.
4.3-2 All System Sluggish
1. System Relief Valve R1 defective or not adjusted
properly.
Adjust valve. Replace if defective.
2. Hydraulic pump P1 worn.
Check system pressure and ow from Pump P1.
Replace if defective.
4.3-3 Platform Drifts Down
1. Defective Lift cylinder seals at the gland.
Replace if damaged.
Note: There are no piston seals, just wear rings.
2. Combination of stuck or defective Holding valves
2H-13-1 and/or 2H-13-2 and defective Relief
valves R3 and/or R4, if equipped.
Check valves. Replace if defective.
4.3-4 Platform Lifts Slowly
1. Defective Lift valve 3H-14. Check valve. Replace if defective.
2. Lift Relief valve R2 is set incorrectly. Check pressures. Replace if defective.
3. Defective Holding valves 2H-13-1 and/or 2H-13-2.
(If equipped)
Check Holding valves 2H-13-1 and 2H-13-2.
Replace if defective.
4. Defective or plugged Lift Orices O2 or O3.
(if equipped)
Clean Orices. Replace if defective.
4.3-5 Platform Does Not Lift
1. Defective Lift valve 3H-14. Check valve. Replace if defective.
2. Hydraulic oil level too low.
Fully lower the platform. Fill hydraulic tank until
uid is at or slightly above the top mark on the
sight glass.
3. Machine overloaded and Overload Lights PL-1
and PL-2 on Emergency Stop buttons ashing.
Check machine limits and reduce weight as
required. Refer to electrical troubleshooting.
4. Defective or plugged Lift Orices O2 or O3.
(if equipped)
Clean Orices. Replace if defective.
5. Leaking or defective Lift cylinders C2 and/or C3.
(if equipped)
Check cylinders and/or Orices. Replace if
defective.