John Deere Combines 6620, Side Hill 6620, 7720, 8820. Hydraulic Operations and Tests - part 5

Leveling System not Activated

LEVELING CYLINDERS—Continued

Leveling to the Left

LEVELING CYLINDER VALVE BLOCK

Operation of Valve Block - Leveling Cylinder Not Activated

Operation of Valve Block -Leveling Cylinder Retracting

LEVELING CYLINDER VALVE BLOCK—Continued

Rephasing of Leveling Cylinders

Rephasing Leveling Cylinders —Continued

To rephase the leveling cylinders, the combine is fully tilted to one side iranually and held for 15 seconds. The manual tiit switch overrides the limit switch and allows the cylinders to fully retract and extend.

When cylinder (M, Fig. 20) is fully retracted, the rephasing orifice and ball check (J) are exposed to oil pressure. This oil pressure unseats ball check (J) and allows oil to flow from the rod end around the cylinder piston to the head end of the cylinder.

If the leveling cylinders are not in phase, cylinder (L, Fig. PO) will not be fully extended Oil going to the head end of cylinder (M) wilf be directed to the head end of cylinder (L) by valve blocks (C) and (F). This cil wifi cause cylinder (L) to fully extend.

When cylinder (L. Fig 20) becomes fully extended, the pressure oil will open ball check (H) and allow oil to flow up transfer tube (I) to valve block (F). Oil is then returned to the leveling control valve through port(E) in valve block (F).

Both ball checks (H and J, Fig. 20) allow only a small amount of oil to flow past them. Therefore, during rephasing. oil pressure will build up until the relief valvo opens. The relief valve in the proportional flow divider will open

Section 360

AUTOMATIC HEADER HEIGHT CONTROL OPERATION AND TESTS

CONTENTS OF THIS SECTION
Page

GROUP 00 - SPECIFICATIONS AND SPECIAL TOOLS

GROUP 05 - GENERAL INFORMATION,
DIAGNOSIS AND TESTS AUTOMATIC HEADER HEIGHT CONTROL

General Information.....................05-1

Electrical Malfunctions...................05-3

Hydraulic Malfunctions...................05-6

Electrical System Tests..................05-8

Hydraulic System Tests.................05-10

GROUP 10 - MECHANICAL SYSTEM AUTOMATIC HEADER HEIGHT CONTROL

Row Crop Heads........................ 10-1

200 Series Platforms....................10-4
GROUP 15 - ELECTRICAL SYSTEM AUTOMATIC HEADER HEIGHT CONTROL

GROUP 20 - HYDRAULIC SYSTEM AUTOMATIC HEADER HEIGHT CONTROL
Page

GROUP 25 - DIAL-A-MATIC HEADER

HEIGHT CONTROL - GENERAL INFORMATION, DIAGNOSIS
AND TESTS

General Information .....................25-1

Electrical Malfunctions . *.................25-3

Hydraulic Malfunctions..................25-12

Hydraulic Tests.......................25-16

GROUP 30 - DIAL-A-MATIC HEADER HEIGHT CONTROL MECHANICAL SYSTEM

Row Crop Heads.......................30-1

200 Series Platforms....................30-2
GROUP 35 - DIAL-A-MATIC HEADER HEIGHT CONTROL ELECTRICAL SYSTEM

GROUP 40 - DIAL-A-MATIC HEADER HEIGHT CONTROL HYDRAULIC SYSTEM
General Information.....................40-1

Main Control Valve.....................40-7

Secondary Control Valve.................40-8

Auto Header Valve .....................40-9

Drop Rate Valve ..............................40-12
General Information .....................20-1

Main Control Valve .....................20-7

Secondary Control Valve.................20-8

Auto Header Valve .....................20-9

Drop Rate Valve ......................20-12

Group 00

SPECIFICATIONS AND SPECIAL TOOLS

SPECIFICATIONS

Content .. 3 4 5 6 ..