Product Introduction 3410022-TL380 Power Steering Fluid Reservoir Cap is the sealing cover for DFL commercial vehicle hydraulic steering oil tank. It isolates the internal steering fluid from outside environment, maintains balanced pressure inside the reservoir and prevents fluid splashing out under bumpy driving. This aftermarket replacement cap solves steering fluid loss, dirt entering the tank and air intake into hydraulic circuit caused by cracked shell, hardened built-in seal and failed pressure balance structure of original caps, avoiding heavy steering feeling and pump cavitation failure for long-distance regional freight trucks.

Product Advantages Oil-resistant engineering plastic shell resists heat from engine compartment and will not deform easily. Integrated rubber gasket maintains stable sealing performance after repeated temperature changes. Built-in pressure balance structure releases excess pressure safely. Each cap undergoes tightness test before delivery, standard thread for quick screwing installation and convenient for routine steering system inspection.

Applicable Models Fit for DFL series medium and heavy-duty commercial trucks, widely used on intercity freight vehicles equipped with hydraulic power steering assembly.

Q1: Why does steering become heavy after air enters the steering oil circuit?
A1: Compressed air inside the fluid causes unstable hydraulic pressure and weakens steering assist output.
Q2: What will happen if the cap’s sealing gasket falls off?
A2: Steering fluid splatters out and dust mixes into oil, speeding up steering pump internal wear.
Q3: Can I tighten the cap excessively for better sealing?
A3: Over-tightening may damage the thread and deform the rubber seal, resulting in persistent leakage.