Skyjack SJ519 TH, Service Manual

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SJ519 TH 216942AC
Hydraulic System Section 4 – Troubleshooting Information
4.3 Hydraulic System
4.3-1 All Controls inoperative
1. Worn or defective pump shaft or coupling
Check pump shaft and coupling. Replace if
defective
2. Hydraulic oil level low Check oil level. Fill to proper level
3. Charge pump P1A is defective Repair or replace if defective
4. RV6 misadjusted or defective Adjust pressure, replace if defective
4.3-2 All Boom Functions Inoperative
1. System pump P2 is defective Repair or replace if defective
2. RV1 misadjusted or defective Adjust pressure, replace if defective
3. EC1 defective Replace if defective
4.3-3 No Boom Raise
1. Stuck or defective joystick JS1
Clean valve. Check operation of valve. Repair or
replace valve as required
2. Stuck or defective lift valve V4
Clean valve. Check operation of valve. Repair or
replace valve as required
3. Stuck or defective lift counterbalance valves CB1
Clean valve. Check O-rings on valve. Repair or
replace valve as required
4. Stuck or defective lift counterbalance valves CB2
Clean valves. Check O-rings on valve. Repair or
replace valve as required
5. Defective lift cylinder C1
Check seals on cylinder. Replace as necessary.
Replace cylinder if defective
4.3-4 No Boom Lower
1. Stuck or defective joystick JS1
Clean valve. Check operation of valve. Repair or
replace valve as required
2. Stuck or defective lift valve V4
Clean valve. Check operation of valve. Repair or
replace valve as required
3. Stuck or defective lift counterbalance valves CB2
Clean valve. Check O-rings on valve. Repair or
replace valve as required