Why does my excavator motor leak when under heavy load?

Heavy load situations often reveal hidden problems inside excavator motors. A motor working smoothly during light tasks might suddenly start leaking once the real pressure begins. Leaks under load are serious warnings. They point to weaknesses that need immediate attention to prevent bigger failures.

The main reason for leaks under heavy load is worn seals. Motor seals must handle high pressure, temperature, and constant movement. Over time, seals harden, crack, or lose elasticity. Once that happens, oil finds its way out during peak load moments. In lighter operations, the seals might still hold. But when load increases, the internal pressure rises sharply. Weak seals cannot handle it anymore.

Another reason is internal wear. Motors with worn bearings, damaged shafts, or pitted surfaces develop gaps inside. These gaps disrupt the smooth flow of hydraulic fluid. Fluid gets forced into areas it should not reach. Under heavy load, the system’s pressure tries to escape through the easiest path—damaged seals and gaps.

Heat also plays a major role. Heavy loads generate more heat inside the motor. If the cooling system is not efficient or the oil is degraded, internal temperatures climb. Heat weakens seals, softens materials, and causes expansion in metals. This combination makes motors more likely to leak.

Oil quality matters as well. Old, contaminated, or wrong-spec oil leads to poor lubrication and overheating. Bad oil increases friction and weakens internal components. In heavy load conditions, this can quickly turn a minor problem into a serious leak.

At Fulian Machinery, we understand how important a healthy motor is for your excavators. Our motors are manufactured using high-precision parts, premium seals, and superior materials. We focus on durability, high load resistance, and long service life. Every Fulian motor goes through strict quality control, ensuring it can handle heavy-duty applications without leaking or losing power.

We offer replacement travel motors, swing motors, and hydraulic pumps for many major brands. Our motors fit perfectly, match OEM standards, and provide cost-effective performance. Fulian’s production facilities are ISO-certified, reflecting our serious commitment to quality and customer satisfaction.

If your excavator motor is leaking under load, it is time to upgrade to a stronger, more reliable solution. Fulian Machinery offers fast quotes, worldwide shipping, and professional support. Protect your investment, avoid costly downtime, and keep your machines performing at their best. Contact us today and let Fulian be your trusted partner in success.

Fulian Operation Team

2025.5.18