Product Manual

Table of Contents Rev. 9/13/2019 LL-PMPS MANUAL

OPERATING THE LIFTER: MANUAL UNITS (AUTOSHIFTER FOOT PUMP)

Manually operated versions of this machine utilize auto-shifting, two-speed pumps. Pump speed is

automatically selected based on the output pressure of the hydraulic system. For example, when the forks are

unloaded, pressure in the hydraulic system is low and the pump operates in high speed mode. Each stroke of the

foot pedal pumps approximately 1.2 cubic inches of oil. When weight is applied to the table, system pressure

increases. At pressures in the range of 800-1000 psi the pump automatically shifts into low speed mode. In low

speed mode, less effort is required to move the pedal because each stroke moves just ~0.44 cubic inches of oil.

The forks rise with each stroke of the foot pedal. However, if too much weight is applied, i.e. weight exceeding

the capacity, a pressure relief valve opens and allows oil to flow back to the hydraulic reservoir rather than to the

cylinder. As a result, the forks will not rise until the weight of the load is either equal to or less than the capacity

(1,200 pounds).

To lower the forks, press the release pedal (item no. 21 on pp. 13-14). A pressure compensated flow control

valve ensures that the fork carriage lowers at a uniform and controlled rate. Never increase the pressure relief

setting more than necessary. Never exceed the pressure rating of the components in the hydraulic system.

PURGING AIR FROM THE PUMP

Air periodically becomes trapped inside the pump and has to be removed. When air is present in the hydraulic

system, you might notice a spongy feel to the foot pedal while pressing it.

To remove air from the system:

1. Completely lower the forks and unload them.

2. Remove the fill plug from the oil reservoir.

3. Disconnect the hydraulic hose from the port on the cylinder and insert the free end of the hose into the fill port of

the reservoir;

4. Pump the foot pedal several times and pay close attention to the stream of oil flowing into the reservoir.

Pockets of air will escape as oil flows into the reservoir.

5. When you no longer see/hear air escaping, reconnect the pump to the cylinder by reattaching the hydraulic

hose to the cylinder port.

6. Check all of the hydraulic lines for oil leaks.

7. Although air has been removed from the pump, air could still be trapped in the cylinder. The next procedure

explains how to remove air from the cylinder.

PURGING AIR FROM THE CYLINDER

A bleeder screw is located at the top of the cylinder. The bleeder screw includes a hose fitting to allow

attachment of a (small diameter) hose. Attach a hose to the screw to divert any oil that escapes during the bleeding

process into a container for proper disposal.

To bleed air from the cylinder:

1. Completely lower the forks and unload them.

2. Gently pump the foot pedal once.

3. Carefully open the bleed screw. The pressure built in the system from pumping the pedal causes air and oil to

flow out of the bleed screw. Pressure will drop as air and oil flow from the cylinder. To pressurize the system,

close the bleed screw and pump the pedal once. Open the bleed screw again to allow more trapped air to

escape.

4. Repeat step 3 until air is completely removed from the cylinder, i.e. only oil flows from the bleed screw.

5. Close the bleeder screw.

6. Check all of the hydraulic lines for oil leaks. Repair all leaks. Once there are no leaks, return the unit to service.