Hydraulics
Why has only one hydraulic function stopped working?
If other functions work normally but the boom, arm, bucket, swing or auxiliary circuit does not, the main pump is often sound. Investigate the affected function’s circuit. Follow the operator’s command through the valve, control block and hoses to the actuator.
Start with the controls
Check whether the machine receives the command from the joystick, pedal, button or position sensor. Also check wiring, solenoid and pilot line. If the electronics see the command, the search narrows.
Pilot or electrical control
The control valve spool needs a command to move. Check pilot pressure at the section, solenoid, power supply, control signal, spool movement and the function’s interlock. No command points to a fault upstream of the control valve.
Control valve section
If the command arrives but there is no movement, check the spool, sticking, contamination, springs, check valves, local relief and internal leakage. Establish whether both directions fail or only one.
Only one direction fails
The boom may lift but not lower, the bucket close but not open, or the arm move out but not in. Focus on one side of the pilot control, one solenoid, valve-block passage, relief or anti-cavitation valve, and the relevant hose or line.
Cylinder or hydraulic motor
If line pressure is present but movement is absent or very weak, check cylinder internal leakage, mechanical seizure, rod or piston damage, hydraulic motor and its brake.
Mechanical obstruction
The hydraulics may be sound while the mechanism is jammed: pin, bush, attachment, gearbox, brake or damaged structure.
What you can observe
Which function and direction fail? Can you hear engine loading or solenoid operation? Are other functions normal, is there a fault code, and did it happen suddenly or gradually?
Related problems
Further service support
Have a fault code?
Problem still there?
If these checks have not identified the cause or the fault returns, contact TSV Servis. The more initial information you provide, the sooner we can identify the next diagnostic direction.
What to send us
Send the machine model, S/N, exact function and failed direction, joystick command status, pilot or electrical control data and pressures in the relevant lines.
Include the make and model, S/N or a nameplate photo, engine model if known, operating hours, exact code or display photo and when the fault occurs.
Also tell us what you have already checked or replaced and the results. Include a photo or short video of the symptom where useful.
+420 722 307 850 · tsvcz@seznam.cz