Skyjack SJ 8831E - 1. All Controls Inoperative; 2. All Systems Sluggish; 3. Brake will Not Release; 6. Work Platform Does Not Lift

SECTION 4, Page 11SJ-800 Series E Battery Powered
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Troubleshooting Information - Hydraulic System
4.2-1. All Controls Inoperative
1. Defective System Dump Valve (2H-21A).
-Check valve. Replace if defective.
4.2-2. All Systems Sluggish
1. Systems contaminated.
-Thoroughly flush Hydraulic System and add new hydraulic oil.
(Refer to Sec. 5, Page 2 for recommendations.)
2. System Relief Valve (R1) setting to low or valve is defective.
-Check Serial Number Plate for correct pressure setting. Replace valve if defective.
4.2-3. Brake Will Not Release
1. Brake Release Valve (2H-30) stuck.
-Check valve. Replace if defective
2. Quick Brake Valve (2H-25) stuck.
-Check valve. Replace if defective.
3. Hand pump (HP-2) bypassing oil.
-Check seals for valve. Replace if defective.
4.2-4. No Steer Left Or Right
1. Stuck or defective Steer Valve (4H-23A) or (4H-24A).
-Check valve. Replace if defective
2. Steer Cylinder (C7) leaking internally.
-Check cylinder. Replace if defective.
3. Gearbox Valve (2H-44) stuck open.
-Check valve and reinstall. Replace if defective
4.2-5. Brakes Will Not Release And No Steering
1. Defective Small Pump (P2).
-Check pump. Replace if defective.
4.2-6. Work Platform Does Not Lift
1. Lift Valve (2H-14D) not shifting or contaminated.
-Clean valve and reinstall.
2. Lowering Valve (2H-13-1) stuck open.
-Check valve. Replace if defective.
3. Manual Lowering Valve (V1) stuck open.
-Check valve. Replace if defective.
4. Brake Release Valve (2H-30) stuck or open.
-Check valve. Replace if defective.
5. Lift Gearbox Valve (4H-33A) not shifting.
-Clean valve and reinstall. Replace if defective.
6. Gearbox Valve (2H-44) stuck open.
-Check valve. Replace if defective.
7. Defective Large Pump (P1).
-Check pump. Repair or replace if defective.