Used hydraulic distributor

How a hydraulic distributor works

The distributor is the crossroads of your machine's hydraulic circuit. It receives high-pressure oil from the pump outlet and directs it to the selected actuator (arm and bucket cylinders, travel motors, rotation motors) according to the position of one or more internal spools. The distributor body houses these spools: by sliding within their bore, they open and close calibrated passages that control the direction of the oil flow and, on proportional models, the flow rate intensity.

A malfunction of the hydraulic distributor (cylinder drift, unusual slowness, lack of pressure response) usually indicates wear on the spools or internal seals, even before mechanical failure. Detecting such defects early helps prevent prolonged downtime of construction machinery.

Double-acting, single-acting: distributor configurations

The two main families of distributors differ by their ability to supply one or two chambers of a cylinder.

• Double-acting hydraulic distributor: oil flows in both directions to the cylinder, enabling active movement in both directions. This is the standard setup for mini-excavators, hydraulic excavators, loaders, and telehandlers. More common in construction machinery, it provides force and precise cycle control in both directions.
• Single-acting hydraulic distributor: only one cylinder chamber is supplied, with return by gravity or a return spring. It is used in specific applications: leveling blades, auxiliary arms, certain attachments. It offers a cost-effective replacement when single-direction movement suffices.
• Cross hydraulic distributor (open center position): the spool's neutral position allows oil flow to circulate freely, preventing unintended pressure build-up in neutral. Used hydraulic open center distributors are available for excavators and loaders from various brands.

Ports, sections, and hydraulic distributor schematic

The number of ports and spool positions is indicated directly on the hydraulic distributor schematic per ISO 1219. A 4/2 distributor (4 ports, 2 positions) controls a double-acting circuit in its basic configuration. A 4/3 distributor (4 ports, 3 positions) adds a neutral position that isolates or freely connects the circuit. Construction machinery typically uses multi-section blocks that combine several hydraulic distributors within one body to simultaneously control multiple actuators.

To select the right port configuration, check the nominal flow rate (L/min) and maximum allowable pressure (bar) marked on the original distributor’s nameplate. These parameters take precedence over mere mounting compatibility.

Hydraulic distributor control types

The spool control method is as important a selection criterion as the hydraulic configuration.

Manual hydraulic distributor

The lever or handle mechanically actuates the spool without electronics. This is the most robust solution for compact machines and quick-attach accessories. A factory-checked used manual hydraulic distributor is often the most cost-effective replacement for equipment that does not require remote control.

12V and 24V electric hydraulic distributor

A solenoid (electromagnet) receives an electrical signal to move the spool. The 12V electric hydraulic distributor equips most compact and light machines (mini-excavators, dumpers, forklifts). The 24V version is standard on heavy machines (excavators of 20 tons and above, wheeled loaders). Before purchasing a used electric hydraulic distributor, verify your system’s supply voltage: a 24V solenoid will not operate on a 12V system.

Proportional hydraulic distributor

The proportional distributor modulates spool opening according to the received signal, allowing precise dosing of flow and actuator speed. It is found on electrohydraulic controlled machines (proportional joystick), telescopic cranes, and equipment requiring fine control. When replacing a used unit, compatibility with the onboard control module must be verified before installation.

Key points to choose your used hydraulic distributor

• Circuit type: double-acting (standard in construction equipment) or single-acting depending on application and actuators to control
• Supply voltage: 12V for light and compact machines, 24V for heavy machinery
• Number of ports and sections: match with the original hydraulic schematic
• Control type: manual, electrohydraulic, or proportional according to onboard control system
• Manufacturer reference: brand, model, and serial number of the machine to confirm flow and pressure compatibility
• Distributor body condition: check that bore surfaces have no scratches or deformation before installation

Hydraulic distributor hookup diagram for loader or mini-excavator

For a loader distributor hookup, identify the four main ports: P (pump pressure), T (tank return), A and B (to actuators). The P port receives oil from the pump, the T port returns unused oil to the tank, and A and B supply the two cylinder chambers depending on spool position.

On a sectional block hydraulic distributor for mini-excavators, each section corresponds to one motion of the machine (left/right travel, rotation, arm, bucket). Reversed hookup does not immediately damage the circuit but reverses movement direction. Low flow testing prior to full pressure build-up is essential to confirm control consistency.

Hydraulic distributor spool: the key wear part

The spool is the moving part sliding inside the distributor body bore to open or close oil passages. It’s the primary wear component to inspect if you notice cylinder drift under load (unintended movement without control input), power loss, or control imprecision. High-pressure cycles enlarge clearances between spool and bore, causing internal leaks.

On some common models, the spool alone can be replaced. On others, replacing the complete used distributor body is better to restore original clearance and ensure reliable long-term function.

Used hydraulic distributors for mini-excavators, loaders, and cranes

Each equipment type has its own flow, pressure, and distributor configuration requirements.

For mini-excavators (1 to 6 tons), the main distributor block controls travel, turret rotation, arm, and bucket simultaneously. Compatibility is tight between brands and models: find our used distributors for JCB , Caterpillar , Liebherr or Volvo TP in our catalog.

For wheeled loaders and backhoe loaders, the hydraulic distributor feeds the arm, bucket cylinders, and front attachments. A used Case or Volvo distributor in good condition can restore a stalled machine at a significantly lower cost than a new part.

For a crane hydraulic distributor kit (boom, jib, or auxiliary truck crane), ensure the chosen distributor matches the flow allowed by the safety valve and the solenoid supply voltage.

Used hydraulic distributors at Codimatra

• Parts from selected dismantlings, tested in our workshop before shipment
• Used double-acting, single-acting, 12V/24V electric, proportional, and open-center distributors available
• Stock covering major construction equipment brands: JCB, Volvo, Liebherr, Case, Bobcat, Komatsu, Mecalac
• Personalized advice: provide brand, model, and original reference to confirm flow and pressure compatibility
• Fast delivery to minimize downtime of your construction machinery