The ball joint (also known as the steering ball joint or ball joint pin) is a key component in the steering system, responsible for connecting the steering rod to the steering knuckle (or wheel hub), allowing the wheels to turn flexibly. The following is a detailed introduction about the truck steering ball joint:
1. Function and Function
Transmitting steering force: The steering force of the steering wheel is transmitted to the wheels through the steering rod.
Multi directional rotation: The ball joint structure allows the wheels to swing up and down during steering (adapting to suspension motion) while maintaining steering control.
Reduce friction: The internal ball seat and lubricant design ensure smooth rotation and reduce wear.
2. Main components
Ball head pin: Steel spherical head, usually surface hardened to improve wear resistance.
Ball seat (bearing sleeve): A wear-resistant material (such as polyurethane or metal) that wraps around the ball joint pin to reduce friction.
Dust cover: Made of rubber or polyurethane material, it prevents dust and moisture from entering and keeps the lubricating grease clean.
Lubricating grease: Internally filled with specialized lubricating grease to reduce wear and corrosion.
3. Common types
Upper Ball Joint: connects the upper control arm to the steering knuckle, usually bearing a small load.
Lower Ball Joint: connects the lower control arm to the steering knuckle, bearing greater weight and impact force.
Integrated vs replaceable: Some trucks use integrated ball joints (integrated with the control arm), which need to be replaced as a whole; The independent ball head can be replaced separately.
4. Symptoms of malfunction
Abnormal noise: make a "clunking" sound when turning (due to damaged dust cover causing lubrication failure).
Loose steering: The virtual position of the steering wheel increases and the handling decreases.
Abnormal tire wear: Loose ball joint leads to inaccurate wheel alignment.
Oil leakage: The dust cover is broken and lubricating grease is leaking out.
5. Maintenance and replacement
Regular inspection: During maintenance, check if the dust cover is damaged and if there is any gap between the ball joints.
Lubrication: Some ball joints are equipped with oil nozzles and need to be regularly lubricated with grease (those without oil nozzles are sealed).
Replacement steps:
Lift the vehicle and remove the wheels.
Remove the fixing bolts of the steering rod or control arm.
Use a specialized tool (ball head separator) to press out the old ball head.
Install the new ball joint and tighten the bolts according to the torque requirements.
Perform four-wheel alignment to ensure correct wheel angles.