Skyjack SJ519 TH, Service Manual

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SJ519 TH 216942AC
Section 4 – Troubleshooting Information Hydraulic System
4. Defective steer cylinder C5 and/or C6
Check seals on cylinder. Replace as necessary.
Replace cylinder if defective
5. Orifice OR1 plugged Remove and inspect, clean or replace as required
6. Relief valve RV14 valve defective
Check O-rings and clean valve. Repair or replace
orbit motor as required
7. Orifice OR2 plugged Remove and inspect, clean or replace as required
4.3-11 Park Brake will not Release
1. Stuck or defective park brake valve 3H-26
Clean valve. Check O-rings on valve. Repair or
replace valve as required
2. Bypassing or defective parking brake seals in
axle Check seals, replace as necessary. Replace if
defective
4.3-12 Park Brake Will Not Engage
1. Defective park brake C11 Repair or replace as necessary
2. Park brake valve SV3 stuck in shifted position Check valve. Replace if defective
4.3-13 Service Brake Will Not Engage
1. Service brake actuator stuck or defective
Clean valve. Check operation of valve. Repair or
replace valve as required
2. Stuck or defective shuttle valve SV1 Clean valve. Repair or replace valve as required
3. Bypassing or defective brake seals in axle
Check seals, replace as necessary. Replace if
defective
4.3-14 No Drive Function Forward or Reverse
1. Defective pump displacement control 4H-15 and
4H-16
Check control. Replace if defective
2. Worn or defective drive pump P1 Check pump. Replace if defective
3. Worn or defective drive motor M1 Check motor. Replace if defective
4. Service brake V12 not releasing
Check brake pedal is returning to up (off) position.
Clean, repair or replace valve as required
5. Park brake not releasing See “park brake will not release” in this section