Ratgeber zur Wahl des passenden Frontladersteuergerätes
Choose the right front loader controls
Technical guide for selection, design, and compatibility
A front loader control unit is the central control element for front loaders on tractors. Choosing the right one is crucial for functionality, safety, the longevity of the hydraulics, and a smooth workflow.
This guide is aimed at agricultural businesses, workshops, and technically proficient users and explains step by step what to consider when choosing a suitable front loader control unit.
What is a front loader control unit?
A front loader control unit is a hydraulic directional valve used to control the movements of the front loader (raising, lowering, tilting, auxiliary functions). It is installed between the pump and the actuator (hydraulic cylinder) and directs the oil flow purposefully.
Typical features:
- Raising and Lowering the Front Loader
- Tilting of the bucket or attachment
- Control of auxiliary functions (e.g. gripper)
Step 1: Identify the tractor's hydraulic system
The installed pump determines the basic design and operating principle of the hydraulic system. Therefore, the pump is fundamentally decisive for the choice of the front loader control unit system.
Possible built-in pump designs:
- Gear pump
- Generates a constant current system (oil is produced continuously)
- also called an open system or open center
- Common for older tractors, smaller tractors, or tractors with simpler equipment
- Relatively compact design, linking multiple pumps is possible
- Example representation:
-
- Caution!
- It may be that the gear pump is used in conjunction with modern valve blocks (example: Bosch SB23 LS); if one wishes to use existing interfaces there, m
- Generates a constant current system (oil is produced continuously)
- Load-sensing adjustable pump
- Ergulates an LS system (hydraulic power is generated only as required in pressure and flow)
- short: LS system
- Common in newer tractors from the mid power class onward.
- example depiction:
- Ergulates an LS system (hydraulic power is generated only as required in pressure and flow)
- Radial piston pump
- Generates a constant pressure system (system is continuously maintained at operating pressure)
- also called closed center or closed system
- Relatively uncommon, various older John Deere tractors are equipped with it
- Generates a constant pressure system (system is continuously maintained at operating pressure)
Step 2: Is a print forwarding required?
Pressure forwarding ensures that, when the control unit is in neutral position, downstream control blocks can be supplied with pressure. In load-sensing systems and constant pressure systems pressure forwarding is not required; this is only relevant for constant flow systems.
Bei tractors with a constant-current system, pressure forwarding is generally always required. Only if no further valves are installed downstream of the additional control unit to be fitted can pressure forwarding be omitted.
Notice!
For the Bosch SB7 and the SB23 OC system, the control units are only supplied with pressure when the oil returns (control unit has the lowest priority), therefore a valve with pressure transfer must always be used for these control units!
Step 3: What does my front loader need?
There are usually two types of construction here:
- 2x Double-acting
- Today a common standard front loader, lowering is done here with pressure, the tractor can usually be lifted via the front loader
- Device operation (tilt forward-backward) is performed via a double-acting front loader
- 1x Single-acting, 1x Double-acting
- Long considered a common configuration for a long time, lowering here is achieved only by the loader's own weight
- Device operation (tilt in/out) is performed via a double-acting hydraulic cylinder
Für beide Varianten wird üblicherweise die Heben/Senken-Sektion mit einer Schwimmstellung ausgestattet.
Unsere front loader control units are usually designed for the first-mentioned configuration; for the second configuration we offer an additional conversion kit. This also enables easy later conversion to the first-mentioned configuration.
The wings are often already equipped with hydraulic clutch(es). There are usually three different versions:
- BG3 coupling
- simple and inexpensive standard version for many swings
- Flat-sealing couplings
- higher flow rate
- less leakage when coupling
- easier to clean
- Multi-coupling
- generally designed as a flat-sealing coupling
- allows simultaneous and non-interchangeable coupling of the front loader connections
- Also combinable with electrical connections
Die übliche Stoll-Multikupplung ist in der Regel kombinierbar mit unseren Faster-Kupplungen.
Alternately, the front loader connections can of course also be connected directly to the control unit without couplings.
Step 4: Identify installation space and measure Bowden cable length.
Depending on the choice of front loader control unit, the desired mounting position must now be identified. The installation position of the control unit is basically arbitrary, but mounting it on the boom has proven effective.
The following points must be observed:
- Routing of the Bowden cables between the control unit and joystick (observe bending radius!)
- Supply feed, return flow and pressure transmission
- Verbindung couplings of the swingarm with the control unit
After the mounting position of the joystick in the cabin has been clarified, the appropriate length of the Bowden cables must now be chosen.
It is advisable to temporarily lay out this path with a rigid cable or something similar for testing.
Step 5: 3rd/4th control circuit or quick drain
Depending on the equipment on the swing arm, the electrical connection for the 3rd/4th control circuit or fast drain must be provided.
Als Verbindung zwischen Frontlader und Schlepper werden üblicherweise 7polige Steckerverbindungen verwendet, wie sie auch bei Anhängern bekannt sind.
Should control be via the joystick, ensure there are a sufficient number of pushbuttons (one pushbutton for each function).
Schritt 6: System decision electrically proportional or mechanical?
Vorteile of the electrically proportional valve
- more sensitive control
- reduced operating forces
- greater flexibility during installation (no rigid Bowden cables)
Disadvantages of the electrically proportional valve
- Costs
- No function during power outage
Advantages of the mechanical system
- Joystick is more robust
- lower costs
- Mehr Ausstattungsoptionen
- Higher fault tolerance
Disadvantages of the mechanical valve
- Higher actuation forces
- low flexibility during installation
Step 7: Installation of the system
Please refer to the instruction provided for download here!
If you have any questions, please feel free to contact us.
FAQ - Good to know!
Wofür benötige ich Rückschlagventile im Frontladersteuergerät?
Check valves on each section are important so the two sections do not affect each other; these are always installed on our front loader control units, but are often not installed on cheaper alternatives
What does internal leakage mean in hydraulic valves?
Every directional valve seals internally purely metallic (the spool has no seals), therefore every directional valve has a certain internal leakage; however, high-quality manufacturing can reduce this to a minimum
Gibt es Möglichkeiten, den Einbau in meinem Schlepper zu vereinfachen?
We offer end plates for various Bosch valve systems that significantly simplify the connection of external valves; they then provide the necessary interfaces to supply the front loader control unit.
What do I need to consider regarding the pressure when selecting the control unit?
It is important that the operating pressure of the tractor or system is lower than the permissible maximum pressure of the front loader control unit. Our standard solutions are approved for an operating pressure of up to 250 bar and are therefore compatible with all common tractors on the market (old and new). Most front loaders are also generally only approved for this pressure.
Welchen Einfluss hat der Volumenstrom bei der Auswahl des Steuergerätes?
There are two basic distinctions to be made. In the load-sensing system, the tractor pump’s maximum flow rate is irrelevant; it adjusts its flow rate according to the demand requested by the front loader control unit.
In the constant-flow system, the oil is continuously circulated by the front loader control unit. It is advantageous here if the permissible flow rate is significantly higher than the actual flow rate in the system, as this reduces the circulating pressure. This lowers the power requirement and the oil heating. Therefore, a tractor with a flow rate of 40 l/min can easily be combined with a control unit that has a permissible flow rate of 90 l/min.
However, a 40 l/min control unit should not be used in a 90 l/min system; this greatly increases recirculation pressure and oil heating (especially at continuously high RPM, for example during road driving).
Kann it happen that I still have to buy an LS version despite having a tractor with a gear pump?
Yes, if you have a tractor with load-sensing-capable control units and want to use an existing interface of those valves (for example at the end plate). This applies, for example, to tractors with Bosch SB23 LS control units. This is not necessarily obvious to a layperson, so you should consult us or your workshop there regarding the further procedure.
Is it possible to convert a front loader control unit from constant flow to load-sensing (or vice versa)?
No, the differences between the systems are very extensive, so a conversion is not economically viable (even though the valves often share the same basic block).
Auch installing a load-sensing front loader control unit into a tractor with a constant-flow system (or vice versa) does not work.
Therefore, choosing the system is very important and should not be done lightly. We are happy to assist with the correct selection of the valve.