Forklifts rely heavily on hydraulic pumps, which are essential parts of various systems such as power steering, braking, suspension, and gear and motor. In this article, we'll focus on the hydraulic pumps found in gear and motor systems.
Hydraulic pumps provide the necessary flow to transmit power to a hydraulic actuator from a prime mover. There are two types of hydraulic pumps: centrifugal and positive displacement. Centrifugal pumps rely on the outlet pressure to transfer fluid, while positive displacement pumps rely independently on pressure.
Positive displacement pumps come in two forms: fixed is placement and variable displacement. Fixed displacement pumps have a constant flow and pressure, while variable displacement pumps are more energy efficient and perform well for variable flow or pressure applications.
One common problem with hydraulic pumps is bad gears, which can occur due to wear, high temperature of the hydraulic fluid, fluid leaks and contamination, and aeration due to air pockets. To check for bad gears, follow these steps:
- Disassemble the pump by unscrewing the bolts located on the side for outside pumps or the bottom for inside pumps.
- Remove the gasket with a sharp object and wipe off excess fluids for clear visibility.
- Measure the clearance between the gears and the pump's housing cover with a straightedge. The clearance is typically between .001 to .004 inches.
- If the measurement exceeds .005 inches, replace the gears immediately. Ensure that the gears are installed correctly and that their measurements are consistent.
- Check the gear teeth clearance to the pump body and ensure that the teeth length is consistent. The clearance is generally between .001 to .005 inches.
- Clean all components before reassembling the pump. Apply petroleum jelly to all inner components.
- Reinstall and prime the hydraulic pump as per the manufacturer's instructions.
If you find that the components are damaged or worn out, replace them. Forklift101 provides hydraulic pump components for all makes and models at inexpensive prices. Remember to have a professional mechanic with expertise in hydraulic pump replacement replace the hydraulic pump and its components.