Checking Depth Control Cylinders for Leakage

SYSTEM DESCRIPTION

To compensate for smaller oil volume in master cylinder (A) rod end, first slave cylinder (B) is 6.4 mm (1/4 in.) smaller diameter than master cylinder. Second slave cylinder (C) is 6.4 mm (1/4 in.) smaller diameter than first slave cylinder.

TEST PROCEDURE

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

1. Fully extend and rephase cylinders.

2. Set depth control so sweeps are at least 50 mm (2 in.) above ground when machine is lowered.

3. Lower machine to depth stop.

4. Position tractor lever(s) in FLOAT position.

5. Shut off tractor engine.

6. Measure and record all cylinder rod lengths (distance from rod guide to rod clevis base).

7. Let machine stand for one hour.

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

9. If any cylinders have retracted 6 mm (1/4 in.) or more, see your John Deere dealer for cylinder diagnosis and repair.

Use following diagnosis chart for three cylinder depth control systems.

Be sure to retest system after repairing a cylinder.

N58905


A-#1 Master Cylinder
B-#2 Right-hand Wing Cylinder (1st Slave)
C-#3 Left-hand Wing Cylinder (2nd Slave)

NX,T10020O -19-08MAR96-1/2

Cylinder No. Length (Start) Length After 1 Hr Difference Retracted * Difference Extended* 10% of Diff. A and B Diagnosis**
1           =A C
2           =B D
3         A+B=   E

 

Key for Diagnosis Chart for Three Cylinder Depth Control System

  • C = Under 6 mm (1/4 in.) - #1 Cylinder is good. If not, repair #1 cylinder.
  • D = #1 Cylinder is good: #2 Cylinder retracts less than 6 mm (1/4 in.) - #2 Cylinder is good.

    #1 Cylinder is bad: #2 Cylinder extends more than "A" - #2 Cylinder is good, otherwise repair #2 cylinder.

  • E = #2 Cylinder is good: #3 Cylinder extends more than "B" - #3 Cylinder is good.

    #1 Cylinder is good and #2 cylinder is bad: #3 Cylinder extends more than "B" - #3 Cylinder is good.

    #1 Cylinder is bad and #2 cylinder is bad: #3 Cylinder extends more than "A+B" - #3 Cylinder is good, otherwise repair #3 cylinder.

  • * = If all cylinders have movement less than 6 mm (1/4 in.), then all three cylinders are good.
  • ** = Use Diagnosis column if one or more cylinders has moved more than 6 mm (1/4 in.).

NX,T10020O -19-08MAR96-2/2