The boom cylinder on an excavator is a hydraulic actuator that controls the motion of the vertical boom arm (or boom) of the machine. The boom is the primary arm for lifting, digging, and dumping material. The boom cylinder takes incoming hydraulic pressure and creates powerful linear motion that allows the operator to raise or lower the boom in a controlled manner, as a single cylinder that has a piston rod (attached to the boom) and a sealed hydraulic chamber (which contains hydraulic oil). The nature of construction, mining, or demolition means that the excavator boom cylinder must withstand extreme loads and extreme abrasive conditions. Generally, the construction, mining and demolitions sites are harsh environments. So boom cylinders are typically fitted with: high strength steel construction and hard-chromed piston rods, and corrosion resistant seals.
How to Use the Boom Cylinder on an Excavator
Pre-Operation Inspection
Prior to using the boom cylinder, check the hydraulic oil level and inspect the boom cylinder for leaks or visible damage. Be sure to have the boom solid on the ground prior to beginning the boom operation, as you do not want sudden movement.
Engage the Hydraulic System
Turn on the excavator’s engine and activate the hydraulic pump. Use the joystick or control lever (typically located on the operator’s console) to engage the boom cylinder circuit.
Raise the Boom
Pull the joystick backward (upward in some excavator brands) to extend the piston rod inside the boom cylinder. Pulling the joystick backward lifts the boom arm relatively smoothly. Pay attention to the loads being lifted and do not over-extend it.
Lower the Boom
Push the joystick forward (downward in some excavator brands) to retract the piston rod—this lowers the boom smoothly when done properly and allows the operator to control the speed at which it is lowered. Be sure there are no personnel or obstacles underneath the boom.
Stop and Hold Position
When you release the joystick, the hydraulic lock valve kicks in, freezing the boom's position for that moment. This is a very useful feature to prevent unwanted movement when you make adjustments for operations.
Post-Operation Maintenance
After you are done with the boom, if your operator manual allows for it, be sure you lower the boom all the way, so that you relieve all of the hydraulic pressure. It's also good practice to clean dirt and debris off of the cylinder to avoid damaging the seal, and for the operator to have it, I particularly recommend taking a quick look at the cylinder anyway to check for oil leaks and abnormal wear.
Pro Tips:
These boom cylinders? Total workhorses. Swapped 'em on our Cat 320 last March—zero leaks, even after 6 months of nonstop demolition. Value for money. .
Our tech check showed our hydraulic cylinders have 22% less friction than the original OEM ones. The precise machining on the piston rods is just right with clearance tolerances, netting us an annual 187 hours less in maintenance for our Komatsu equipment. And there’s detailed quality control paperwork accompanied the shipment.
Bloody ripper! These cylinders laugh at our red dirt. Had 'em in the Pilbara heat for 14 months—still tighter than a drum. Their Singapore warehouse got us replacements in 3 days when we smashed one on a boulder. Legends!
We appreciate all the care you take in providing dimensionally accurate products. The custom stroke length cylinders that were ordered for our Hitachi ZX490 were made to our exact specifications, and with the accompanying 3D inspection reports, we had complete traceability. Your technical support team was responsive and made it easy for integration into our preventative maintenance schedule.
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