Safety Handbook for Hydraulic Systems
The components described in the first section of this handbook are connected together to form a basic hydraulic system as shown below.
Basic Hydraulic System
NPT connections require thread sealant. Leave first thread bare to prevent sealant from entering hydraulic system.
For easy make/break connections, install a coupler in the gauge adaptor port. Then use a hose with a coupler end instead of a threaded end.
Before Using the Hydraulic System
- Check that all connections are tight and leak free. It is especially important to check all coupler connections because, after the system has been pressurized, you will not be able to tighten the couplers by hand and using tools will damage the couplers.
- Remove air from system.
- Check oil level in pump reservoir. Fill only to level indicated on the pump. Over-filling the reservoir may cause the pump to malfunction. Fill the reservoir only when all cylinders have been retracted. If you add oil when the cylinder is extended, the reservoir will overflow or be pressurized when you retract the cylinder.
- When using an electric, air, or gas powered hydraulic pump, energize the pump only when the directional control valve is in the neutral position.
- In lifting systems, use lifting bases that spread out the load. This reduces the contact pressure between the cylinder and the floor and avoids sinking or punching of the floor. Most working floors cannot withstand high loads.
- Use shut-off valves for temporary load holding. Never hold a load on a coupler or directional control valve.
- Never get under a load.
- Use cribbing for load holding for long periods.
- Do not use hose to lift or pull equipment.
Removing Air from the Hydraulic System:
How to tell if there is air in the system
Hydraulic system operation should be instant and smooth. For every pump stroke, the cylinder should rise evenly. If the cylinder movement is erratic or jerky, there may be air in the system.
How to remove air from the system
Air will always go to the highest point in the system. This includes the inside of the cylinder plunger. That is why the cylinder must be turned upside down (single-acting) or laid on its side (doubleacting) to get the air out. To remove air from the system, position setup as illustrated below.
NOTE: double-acting cylinders must have the couplers facing up.
Fully advance and retract the cylinder 2 or 3 times. You can usually hear the air escaping through the reservoir.
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