Hydraulic System; All Functions Inoperative; All Functions Sluggish; Platform Drifts Down - Skyjack SJ 3215 Service Manual

Service and Maintenance

Hydraulic System

4.2-1

All Functions Inoperative

1. Proportional valve 2H-59 defective or is sticking.
- Check valve. Replace if defective.
2. Compensator portion of proportional valve defective or is sticking.
- Check valve. Replace if defective.
3. Pump P1 defective.
- Check pump. Replace if defective.
4.2-2

All Functions Sluggish

1. System relief valve R1 defective or not adjusted properly.
- Adjust valve. Replace if defective.
2. Hydraulic pump P1 worn.
- Check pump. Replace if defective.
4.2-3

Platform Drifts Down

1. Defective lift cylinder gland seal.
- Check for hydraulic oil leaking from the gland seal. Rebuild cylinder. Replace if damaged.
2. Combination of: Defective holding valve 2H-13-1 and either defective lowering valve 2H-13 or relief
valve R2 or manual lowering valve V1. (ANSI/CSA)
- Check valves. Replace if defective.
Combination of: Defective holding valve 2H-13B-1 and either defective lowering valve 2H-13B or relief
valve R2 or manual lowering valve V1. (CE)
- Check valves. Replace if defective.
3. Defective o-ring between lift cylinder and holding valve manifold block or loose bolts holding the
manifold.
- Check for hydraulic oil leaking from between cylinder and manifold. Tighten bolts on manifold
or replace o-ring. Replace manifold if damaged.
4.2-4

Platform Lifts Slowly

1. Open or leaking manual lowering valve V1.
- Close valve. Replace if defective.
2. Lift relief valve R2 defective or not adjusted correctly.
- Adjust valve. Replace if defective.
3. Open manual override on holding valve 2H-13-1 (ANSI/CSA) or 2H-13B-1 (CE).
- Depress and turn manual override clockwise to close. Replace if defective.
4. Stuck or defective deceleration valve 2H-13A (Model 3215 ANSI/CSA) or 2H-13C (Model 3215 CE).
- Check valve. Replace if defective.
4.2-5

Platform Does Not Lift

1. Open manual lowering valve V1.
- Close valve. Replace if defective.
2. Hydraulic oil level too low.
- Fully lower the platform. Fill hydraulic tank with recommended fluid to appropriate level.
3. Platform weight excessive.
- Reduce platform load to maximum capacity.
4. Up valve 3H-14 defective or is sticking.
- Check valve. Replace if defective.
5. Plugged deceleration valve 2H-13A (Model 3215 ANSI/CSA) or 2H-13C (Model 3215 CE).
- Clear obstruction from valve. Replace if defective.
SJIII Compact Series
143909
Section 4 - Troubleshooting Information
SKYJACK, Page 11