The seals in an excavator's boom cylinder are designed to prevent hydraulic fluid from leaking out and to keep contaminants from entering the hydraulic system. If these seals become worn or damaged, you may notice several issues. Common signs include hydraulic fluid leaks around the cylinder, decreased lifting power, and irregular operation of the boom. Ignoring these issues can lead to more severe problems, including complete hydraulic failure, which can result in costly repairs and downtime.