It is time-consuming to thoroughly check the hydraulic system before and after each use. However, most hydraulic systems are not checked until the operator complains of poor performance. By this time, it may be too late to prevent a major repair. Aside from regular maintenance described in the owner’s manual, follow these basic procedures every 50 hours or so to determine the health of your system and prevent costly failures. Once you have located a problem, contact a professional hydraulic technician to do most repair work. They can ensure that all of the specifications and tolerances within the system are maintained.

Inspecting for restricted flow

Slow hydraulics are the result of restricted flow. Low oil level, restricted hoses and lines, and damaged valves, pumps, cylinders and motors are all possible causes.

1. Activate the hydraulic system and determine which individual system components are operating slowly. If, for instance, the bucket on your skid-steer loader does not raise or lower at the normal speed, but other hydraulic attachments do, then the restriction is in the lines and components that service the bucket. Visually inspect these components for leaks. Pay particular attention to connecting points.

2. If no external restriction is obvious, then the obstruction may be internal. Large contaminants may be blocking a valve or have become lodged in part of a cylinder or motor.

3. If you cannot isolate the obstruction and the entire system is operating slowly, then check the pump. If you hear the sound of cavitation, then the pump is not getting enough flow. Determine that the fluid levels are adequate and the all filters and strainers are clean. If the problem persists, check the inlet line to make sure that there is no blockage or kinking. Also, verify that the pump shaft is operating and not damaged.

Inspecting for weak hydraulics

Weak hydraulic response is the result of low pressure. The system may be delivering the amount of flow desired, but due to pressure leaks, the system does not efficiently use the flow to perform work. Pressure problems can result from damaged pumps, worn valves and worn components in motors and cylinders. If, for example, your bucket does not lift as much weight as it should, then there is a leak in the path of flow that is allowing pressure to be lost. To check a bucket attachment, perform the following steps (or comparable steps for other components).

1. Raise the bucket to full height and shut off the engine. Remove pressure from the line by moving the control lever back and forth once or twice. Then look carefully to see if the bucket begins to creep downward. If it does, the leak could be in the cylinder, or a valve that controls flow to the bucket, or both.

2. Block the raised bucket and disconnect the hose that is not under pressure from the cylinder. Now, unblock the bucket. If you notice oil seeping from the port, the cylinder is leaking. If no leak is noticed at the cylinder, then a valve may be defective.

3. Do this to all attachment points on the hydraulic system. If you cannot pinpoint the leak to a specific location, then the pump or one of the primary valves may be leaking.

4. To verify that internal leaks are occurring, check the oil for excess heat. If internal leaks are present, oil is forced through small spaces where the leak is. This increases friction and causes the oil to heat up.