Checking Depth Control Hydraulic System

Purpose of this procedure is to determine if total hydraulic depth control system is functioning properly. Based on results found at conclusion of this test, it may be necessary to perform other diagnostic procedures in order to identify specific area which is malfunctioning.

causym CAUTION: Escaping fluid under pressure can penetrate skin causing serious injury. Avoid hazard by relieving pressure before disconnecting hydraulic or other lines. Tighten all connections before applying pressure. Search for leaks with a piece of cardboard. Protect hands and body from high-pressure fluids.

If an accident occurs, see a doctor immediately. Any fluid injected in skin must be surgically removed within a few hours or gangrene may result. Doctors unfamiliar with this type of injury may call Deere & Company Medical Department in Moline, Illinois, or other knowledgeable medical source.

IMPORTANT: Warm hydraulic oil to normal operating temperature before performing system check.

1. With machine unfolded, check all hoses, hydraulic fittings, and cylinder rod seals for external leaks. Repair all external leaks before continuing procedure.

2. Turn single point crank so valve is not activated.

3. Cycle machine up and down three times.

NOTE: Hold tractor lever in extend position for five seconds at end of each upward stroke to rephase cylinders.

4. Adjust single point depth control so soil engaging tools stop just above ground.

5. Position tractor lever(s) in NEUTRAL position.

6. Measure and record all depth control cylinder rod lengths.

7. Allow machine to sit idle for 30 minutes.

8. Re-measure and record all depth control cylinder rod lengths.

9. Compare your results below:

a. If none of cylinders have retracted or extended more than 6 mm (1/4 in.), hydraulic system is operating correctly.

b. If all cylinders retracted uniformly, more than 6 mm (1/4 in.), repair single point depth control valve.

c. If any uneven retraction, more than 6 mm (1/4 in.), is measured between cylinders or if any cylinder(s) extended more than 6 mm (1/4 in.), see CHECKING FOR DEPTH CONTROL CYLINDER LEAKAGE.

NX,980P97,A7C -19-02APR97-1/1