Overview
When a hydraulic press stops working, the problem typically traces to one of three areas: hydraulic fluid, mechanical components, or electrical systems. A systematic approach is the most effective way to identify the cause.
1. Start with Hydraulic Fluid
Hydraulic fluid is the most critical part of the system. Problems here are the leading cause of poor performance and complete failure.
1.1 Check Fluid Level
The most common reason a press will not work is low fluid in the reservoir. Low levels cause the pump to suck air instead of fluid, preventing pressure build-up.
1.2 Check for Contamination
- Milky appearance may indicate water contamination
- Dark color with burnt smell indicates overheating and degradation
- Debris or particles indicate internal wear or filter failure
Contaminated fluid clogs valves and damages pumps.
1.3 Confirm Fluid Type and Viscosity
- Too thick: May not flow properly, especially when cold
- Too thin: Reduces pump efficiency and increases wear
1.4 Listen for Air in System
If the pump makes loud whining, rattling, or knocking sounds, air may be present due to low level or suction-side leaks.
2. Investigate Mechanical Failures
2.1 Identify External Leaks
Visible puddles on the floor are obvious signs. Inspect hoses, fittings, and seals around cylinder and pump carefully.
2.2 Consider Internal Leaks
Even without visible leaks, the press may feel weak or sag under load, pointing to internal leakage from worn seals or valve malfunctions.
2.3 Check Pump and Motor
- Ensure electric motor is running
- Check coupling between motor and pump is intact
- A sheared coupling causes total function loss even if motor hums
2.4 Inspect Relief Valve
The relief valve may become stuck open, dumping fluid continuously back to reservoir and preventing pressure build-up.
3. Electrical Faults
3.1 Confirm Power Supply
Check for tripped breakers or fused fuses. Verify main power breaker is on.
3.2 Test Switches and Controllers
Buttons, foot pedals, and selector switches wear over time. A faulty Start button can make machine appear completely dead.
3.3 Check Solenoids and Sensors
If solenoid coil burns out or connections loosen, the controlled valve will not function.
