- Hydraulic Tank
- Piston Pump (Implement and Steering)
- Main Control Valve Group (Implement)
- Boom Cylinder Group
- Load Control Valve Group (Boom Cylinder Lock)
- Telescoping Cylinder Group
- Load Control Valve Group (Telescoping Cylinder)
- Tilt Cylinder Group
- Load Control Valve Group (Tilt Cylinder Lock)
- Compensating Cylinder Group
- Load Control Valve Group (Compensating Cylinder Lock)
- Frame Leveling Cylinder
- Load Control Valve (Frame Leveling Cylinder) (Lock)
- Diverter Valve Group
- Coupler Cylinder Group (If equipped)
- Combination Valve Group (If equipped)
- Hitch Cylinder Group (If equipped)
Hydraulic Tank
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| Illustration 1 | g00998371 |
Hydraulic tank | |
The hydraulic tank is located at the rear of the operator compartment.
The tank supplies oil to the following machine systems:
- Steering
- Braking
- Transmission
- Implements (Including the Boom, Work Tools, and Trailer and Towing Hitch Hydraulic System)
Piston Pump (Implement and Steering)
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| Illustration 2 | g00902945 |
Piston pump (implement and steering) | |
The pump is mounted on the transmission case.
The pump has permanent drive. Pump output is controlled by steering pressure or implement pressure and flow.
The pump delivers oil to the following systems:
- Steering
- Braking
- Implements (Including the Boom, Work Tools, and Trailer and Towing Hitch Hydraulic System)
Reference: See Systems Operation/Testing and Adjusting, "Piston Pump (Implement and Steering)" for more information.
Compensator Valve
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| Illustration 3 | g00902949 |
Compensator valve (piston pump) | |
The compensator valve is bolted to the piston pump.
The compensator regulates the pump output flow in response to the following oil pressures:
- Load sensing oil pressure
- Supply oil pressure from the pump outlet
Note: Load sensing oil pressure is sometimes referred to as signal oil. The two terms have the same meaning throughout this story.
The compensator valve also serves as a backup for limiting the maximum system pressure.
Main Control Valve Group (Implement)
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| Illustration 4 | g00902950 |
Main control valve (implement) | |
The Main Control Valve Group (Implement) is located at the rear of the machine. The Main Control Valve Group (Implement) consists of the Electronic Pilot Valve Group (Implement) and the bank of 4 Control Valves. The valves are directional control valves.
The Control Valves control the flow of oil to the machine implements and from the machine implements.
Reference: See Systems Operation/Testing and Adjusting, " Main Control Valve Group (Implement)" for more information.
The bank of 4 Control Valves includes the following four implement sections:
- Control Valve (Boom EXTEND/RETRACT)
- Control Valve (Auxiliary)
- Control Valve (Tilt)
- Control Valve (Boom RAISE/LOWER)
The Main Control Valve Group (Implement) also includes the following sections.
- Inlet Manifold
- Outlet Manifold
Inlet Manifold
Valve Assembly (Steering Priority)
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| Illustration 5 | g00902951 |
Valve Assembly (Steering priority) | |
The Valve Assembly (Steering priority) is located in the inlet manifold for the main control valve.
The steering priority valve divides the flow of oil from the piston pump between the demands from the steering system and the demands from the implement system.
Relief Valve (Load Sensing Oil)
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| Illustration 6 | g00902952 |
Relief Valve (Load sensing oil) | |
The load sensing relief valve is located in the inlet section for the control valve.
The Relief Valve (load sensing oil) is used to limit the maximum system pressure. The relief valve is adjustable.
Note: Relief Valve (load sensing oil) is sometimes referred to as the signal limiter valve. The two terms have the same meaning throughout this story.
Reference: See Systems Operation/Testing and Adjusting, " Main Control Valve Group (Implement)" for more information.
Flow Control Valve Group (Dump Valve for Load Sensing Oil)
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| Illustration 7 | g00902953 |
Flow Control Valve Group (dump valve for load sensing oil) | |
The Flow Control Valve Group (dump valve for load sensing oil) is located in the inlet manifold for the control valve.
The flow control valve provides a drain back to the hydraulic tank for the load sensing oil after the load has gone.
Reference: See Systems Operation/Testing and Adjusting, " Main Control Valve Group (Implement)" for more information.
Note: Load sensing oil pressure is sometimes referred to as signal oil. The two terms have the same meaning throughout this story.
Outlet Manifold
Relief Valve (Pressure Reducing Valve)
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| Illustration 8 | g00902954 |
Relief Valve (pressure reducing valve) | |
The pressure reducing valve is located in the outlet manifold for the control valve.
The pressure reducing valve provides a supply of oil to the pilot system and the brake system at a reduced pump supply pressure.
Trailer and Towing Hitch Hydraulic System (Option)
Combination Valve Group (Trailer and Towing Hitch Hydraulic System )
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| Illustration 9 | g00998874 |
(1) Combination Valve Group (2) Towing Hitch Group (3) Cable Group (4) Trailer socket | |
The hydraulic system for the trailer and the towing hitch contains the following items: electrically controlled Combination Valve Group (1), Towing Hitch Group (2), hitch control Cable Group (3), trailer socket (4), additional oil lines and control switch that is mounted in the cab
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| Illustration 10 | g00998873 |
Location of the Combination Valve Group | |
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| Illustration 11 | g00998898 |
(1) Combination Valve Group (3) Hitch control Cable Group | |
 | |
| Illustration 12 | g00998922 |
(1) Combination Valve Group | |
Combination Valve Group (1) is mounted to the rear of the frame. The oil lines attach to the outlet manifold of the main control valve. The oil lines route pressure oil, load sensing oil, and return oil to the combination valve.
The brake oil for the trailer is supplied by an oil line that is connected to the front axle brake.
 | |
| Illustration 13 | g00998890 |
Towing Hitch Group | |
The Towing Hitch Group is mounted to the rear frame. Hitch control Cable Group (3) moves the hooks that release the hitch. A cylinder, that is located inside the Towing Hitch Group, lowers the hitch when the operator activates the control switch that is located inside the cab. The cylinder also raises the hitch when the operator activates the control switch in the opposite direction.
Boom Cylinder
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| Illustration 14 | g00998370 |
Boom cylinder | |
The cylinder is located under the boom. The cylinder head end is attached to the machine frame and the cylinder rod end is attached to the boom.
The cylinder is a double acting cylinder. The cylinder is used to raise the boom. The cylinder is also used to lower the boom.
Load Control Valve (Boom Cylinder Lock)
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| Illustration 15 | g00998366 |
Load control valve (boom cylinder lock) | |
The load control valve is attached to the lower end of the boom cylinder.
The load control valve locks oil into the head end of the cylinder in order to hold the cylinder in position when the cylinder is stationary.
The load control valve prevents the boom cylinder from lowering in the event of a loss of hydraulic power. The load control valve also prevents the boom cylinder from collapsing if a hydraulic hose bursts.
Reference: See Systems Operation/Testing and Adjusting, "Load Control Valves (Lock Valves)" for more information.
Telescoping Cylinder
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| Illustration 16 | g00902958 |
Telescoping cylinder | |
The cylinder is located inside the boom. The cylinder assembly is attached to the rear of the outer section of the boom by a trunnion. The rod end is attached to the inner boom section. The cylinder is supported by a pad and slides inside the boom.
The cylinder is a double acting cylinder. The cylinder is used to extend the boom. The cylinder is also used to retract the boom.
Load Control Valve (Telescoping Cylinder Lock)
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| Illustration 17 | g00902959 |
Load control valve (telescoping cylinder lock) | |
The load control valve is attached to the rear of the telescoping cylinder.
The load control valve locks oil into the head end of the cylinder in order to hold the cylinder in position when the cylinder is stationary.
The load control valve prevents the telescoping cylinder from retracting in the event of a loss of hydraulic power. The load control valve also prevents the telescoping cylinder from collapsing if a hydraulic hose bursts.
Reference: See Systems Operation/Testing and Adjusting, "Load Control Valves (Lock Valves)" for more information.
Tilt Cylinder
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| Illustration 18 | g00902960 |
Tilt cylinder | |
The tilt cylinder is mounted inside the boom head. The cylinder head end is attached to the boom head and the rod end is attached to the linkage for the quick coupler.
The cylinder is a double acting cylinder that is used to tilt the carriage forward and backward.
Reference: See Systems Operation/Testing and Adjusting, "Main Hydraulic System" for more information.
Lock for Load Control Valve (Tilt Cylinder)
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| Illustration 19 | g00998270 |
Load control valve (tilt cylinder) (lock) | |
The load control valve is installed into the head end of the tilt cylinder.
The load control valve locks oil into the head end of the cylinder in order to hold the cylinder in position when the cylinder is stationary.
The load control valve also prevents the tilt cylinder from collapsing if a hydraulic hose bursts.
Reference: See Systems Operation/Testing and Adjusting, "Load Control Valves (Lock Valves)" for more information.
Compensating Cylinder
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| Illustration 20 | g00998259 |
Compensating cylinder | |
The cylinder is located at the bottom of the boom at the rear of the machine. The head end of the cylinder is attached to the outer section of the boom and the rod end is attached to the machine frame.
The cylinder is a double acting cylinder. The compensating cylinder works with the tilt cylinder in order to maintain the selected angle of the carriage when the boom is raised and lowered. The compensating cylinder and the tilt cylinder utilize the same oil lines and the same control valve.
Reference: See Systems Operation/Testing and Adjusting, "Main Hydraulic System" for more information.
Load Control Valve (Compensating Cylinder Lock)
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| Illustration 21 | g00999113 |
Load control valve (compensating cylinder lock) | |
The load control valve is installed onto the bottom of the outer section of the boom.
The load control valve prevents high pressure in the head end of the tilt cylinder from entering into the head end of the compensating cylinder.
Frame Leveling Cylinder
 | |
| Illustration 22 | g00902970 |
Frame leveling cylinder | |
The frame leveling cylinder is located at the front of the machine on the right side. The head end of the cylinder is attached to the machine frame, and the rod end is attached to the front axle.
The frame leveling cylinder allows the machine frame to be levelled in order to improve the stability of the machine during operation.
Reference: See Systems Operation/Testing and Adjusting, "Frame Leveling System" for more information.
Lock Valve (Frame Leveling Cylinder)
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| Illustration 23 | g00902971 |
Lock valve (frame leveling cylinder) | |
The lock valve is attached to the casing of the frame leveling cylinder.
The valve controls the flow of oil into the cylinder and out of the cylinder. The valve also locks oil into both sides of the cylinder in order to hold the cylinder in position when the frame leveling system is in HOLD.
Diverter Valve
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| Illustration 24 | g00999160 |
Diverter Valve (auxiliary single) | |
 | |
| Illustration 25 | g00902965 |
Control Valve (dual auxiliary) | |
The diverter valve is installed on the left side of the boom head.
On TH220B standard machines, a single Diverter Valve (auxiliary single) is installed. A dual Control Valve (dual auxiliary) is installed as an option on the TH220B machines. The single Diverter Valve (auxiliary single) and the dual Control Valve (dual auxiliary) are available options on the TH330B and TH340B machines.
The single valve diverts the oil flow from the auxiliary circuit section of the implement main control valve to either the quick coupler cylinder or through Fitting Assembly (quick disconnect) to a work tool cylinder. The dual diverter valve provides an oil flow to an additional auxiliary service.
Reference: See Systems Operation/Testing and Adjusting, "Auxiliary Control (Combined Circuit)" for more information.
Quick Coupler Cylinder
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| Illustration 26 | g00902967 |
Quick coupler cylinder | |
The quick coupler cylinder is located in the hydraulically operated quick coupler.
The hydraulic quick coupler allows the operator to change the work tools on the quick coupler without leaving the cab.
The rods of the quick coupler cylinder serve as pins. The rods extend out of the cylinder in order to engage the work tool that is attached to the quick coupler and the rods retract into the cylinder in order to disengage the work tool that is attached to the quick coupler.
Reference: See Systems Operation/Testing and Adjusting, "Auxiliary Control (Combined Circuit)" for more information.