10 Brake(S) Will Not Release (Wet Brakes); 11 Mewp Will Not Hold On A Grade (Wet Brakes); 12 Platform Does Not Steer; 13 High/Low Torque Inoperative - Skyjack SJ3220 Service Manual

Section 4 – Troubleshooting Information

4.3-10 Brake(s) will not Release (Wet Brakes)

1. Brake Release valve 3H-17 is defective.
2. Brake Override valve V1 is defective.
3. Defective internal brake piston seals.
4. Defective Brakes BR1 and/or BR2.

4.3-11 MEWP will not hold on a Grade (Wet Brakes)

1. Worn or damaged brake discs.
2. Broken or damaged brake compression springs.
3. Defective Brakes BR1and/or BR2.

4.3-12 Platform does not Steer

1. Right Steer valve 4H-23A and/or Left Steer valve
4H-24A is defective.
2. Steer cylinder C1 seal leaking.
3. Steering cylinder Orifice 01 is plugged.
4. Mechanical binding in kingpins.

4.3-13 High/Low Torque Inoperative

1. Speed valve 3H-18A-1 and/or 3H-18A-2 are stuck
or defective.
2. Differential valve 2H-18A is defective.

4.3-14 Platform Power Deck Inoperative (if option installed)

1. Platform Extend valve 4H-26 and/or Platform
Retract valve 4H-27 is defective.
2. Platform cylinders C5 and/or C6 (if installed) seal
leaking or is defective.
3. Mechanical binding in platform rails, rollers,
guides, etc.
223198ABA
119
Check valve. Replace if defective.
Check valve. Replace if defective.
Check brake pack will maintain pressure. If
pressure is not maintained replace seals.
Inspect wheel assembly. Repair and replace as
necessary.
Inspect brake discs for wear. Replace if worn or
damaged.
Check springs. Replace if defective.
Inspect wheel assembly. Repair and replace as
necessary.
Check valves. Replace if defective.
Rebuild cylinder. Replace if damaged.
Clean orifice. Replace if damaged.
Check for binding. Repair as needed.
Clean valves and check operation. Replace if
defective.
Clean valve and check operation. Replace if
defective.
Check valves. Replace if defective.
Rebuild cylinder(s). Replace if damaged.
Check for binding. Repair as needed.
SJ3220, SJ3226, SJ4720, SJ4726, SJ4732
Hydraulic System