Lift and Tilt Cylinders. Doosan G33P-5 Plus

Problem: Spools do not return to neutral.

Probable Cause:

1. The springs are broken.

2. The spool is bent.

3. The system or valve has foreign particles in it.

4. The control linkage is not in alignment.

5. The fastening bolts of the valve have too much torque.

Problem: No motion or slow, then a too sudden action of the hydraulic system.

Probable Cause:

1. The relief valve is not correctly set, or will not move in base and/or is worn.

2. There is air in the system.

3. Dirt or foreign particles between relief valve control poppet and its seat.

4. Valve body has a crack inside.

5. Spool not moved to a full stroke.

Lift and Tilt Cylinders

Problem: Leakage around the cylinder rod.

Probable Cause:

1. Cylinder head (bearing) seals are worn.

2. Cylinder rod is worn, scratched or bent.

Problem: There is leakage of oil inside the cylinder or loss of lift or tilt power.

Probable Cause:

1. The piston seals are worn and let oil go through.

2. Cylinder has damage.

Problem: The piston rods show wear.

Probable Cause:

1. The cylinders are not in correct alignment.

2. Oil is dirty.

Problem: Foreign material behind the wiper rings causing scratches on the cylinder rod.

Probable Cause:

1. The wiper rings show wear and do not remove dirt and foreign material.

Vehicle System 52 Testing & Adjusting