| Pump runs but output is weak |
Diaphragm assembly, pump head, pressure valve needle, stem valve, springs, O-ring, and hydraulic piston |
Inspect for diaphragm damage, worn pressure-control parts, restricted movement, leakage, or loss of hydraulic force. |
| Fluid delivery pulses or fluctuates |
Diaphragm, regulating spring, pressure knob, valve needle, hydraulic piston, and housing |
Check for uneven diaphragm movement, sticking pressure components, worn springs, trapped air, or hydraulic leakage. |
| Leakage near pump head or cover |
Pump head, diaphragm ring, diaphragm assembly, gasket, O-ring, seal, hydraulic cover, and housing |
Identify whether the leak is coating or hydraulic fluid, then inspect mating surfaces and all related seals. |
| Pressure adjustment does not respond |
Pressure knob, set screw, stem valve, regulating spring, pressure valve needle, and piston spring |
Confirm the knob and set screw engage correctly, then inspect the internal pressure-control stack for wear or sticking. |
| Grinding, knocking, or heavy vibration |
Eccentric sleeve and bearing, shaft key, motor, retaining ring, hydraulic piston, and housing |
Stop operation and inspect drive alignment, bearing condition, key retention, motor mounting, and internal interference. |
| Motor runs but pump does not stroke |
Motor, shaft key, eccentric bearing assembly, hydraulic piston, diaphragm, and retention hardware |
Verify mechanical drive transfer from the motor to the eccentric and hydraulic piston before replacing the motor. |
