Symptoms of Tow Truck Hydraulic System Failures

Most vehicles exhibit signs before a failure occurs, and specialized vehicles like tow trucks are no exception. The hydraulic systems in tow trucks can show certain symptoms indicating potential issues. If operators recognize these signs early and address them promptly, it can significantly extend the lifespan of the vehicle.

Key Symptoms of Hydraulic System Failures:

1. Erratic Cylinder Movement:

• A normally operating hydraulic cylinder runs smoothly at a constant speed. If the forward speed becomes erratic, or if there are shaking, delayed, or irregular movements when a command is issued, and the vehicle produces an abnormal, piercing noise during operation, this is likely due to hydraulic oil contamination.

2. Hydraulic Cylinder and Motor Stalling:

• If the tow truck operates normally at first but then the hydraulic cylinder and motor stop moving despite increased throttle and no issues in the multi-way valve linkage mechanism, this could be due to a stuck primary valve spool in the safety valve of the multi-way valve. The spool, which has a slide valve structure, may be stuck by burrs and cannot reset because the spring cannot overcome the sticking force. Removing the burrs and cleaning the safety valve, then reinstalling it, can restore normal operation.

3. Sluggish Button Responses:

• If a tow truck‘s multi-way valve uses a solenoid directional valve and after several years of use, the button responses become sluggish, it indicates a hydraulic system issue. If not addressed promptly, the buttons may stop responding altogether, indicating that the hydraulic system is non-operational. This often happens because the screws securing the solenoid have loosened, causing the solenoid valve core to shift and fail to activate, preventing pressure oil from reaching the hydraulic cylinder. Tightening the screws can resolve this issue.

Recognizing these symptoms and addressing them promptly can prevent more severe failures and maintain the efficiency and longevity of tow truck hydraulic systems. Whether dealing with a tow truck, a mixer truck, or a truck-mounted crane, understanding these common issues and repair techniques can alleviate concerns and ensure smoother operation.