Common if the rubber splits.
Water and grit then get in and they wear badly, as the grease supports the abrasive and the water helps corrosion. Replace any ball joint you find that has a split rubber boot. They aren't difficult to remove with a tool. If the steering ball joints are replaced be careful, as you can ruin the wheel alignment.
Item 7 under the hub. This holds the suspension together, so rusty is a roadworthy failure.
Water and grit then get in and they wear badly, as the grease supports the abrasive and the water helps corrosion. Replace any ball joint you find that has a split rubber boot. They aren't difficult to remove with a tool. If the steering ball joints are replaced be careful, as you can ruin the wheel alignment.
Item 7 under the hub. This holds the suspension together, so rusty is a roadworthy failure.