How To Diagnose A Failing Steering Knuckle

Steering knuckles are an important part of your car's steering system. They are located right behind each front wheel. The steering knuckle serves as a reliable connection between the wheel, the tie rod, and the suspension system. (Read more here about how a steering knuckle works.)

Like all moving car parts, a steering knuckle can fail. If you suspect that one of your steering knuckles is damaged, this article will help you officially diagnose the problem.

Causes Of Steering Knuckle Failure

New Subaru steering knuckle

It’s not uncommon for a steering knuckle to get cracked or bent. Sometimes a heavy impact from a pothole or object on the road causes damage. Small obstacles (such as potholes) are usually nothing to worry about since your shocks take most of the impact. But a small obstacle combined with spirited driving can also cause damage. For instance:

  • Hard Braking: Braking obviously restricts your wheel from rolling easily over an obstacle. This places torque on your steering knuckle. High torque from heavy braking combined with force from the impact can overwhelm the knuckle.
  • Turning the Wheels: Wheels transmit the least force from hitting an obstacle when they are rolling straight ahead. As soon as the wheels are turned, extra force is transmitted to the knuckle. High speeds while turning multiply that force. If the car is sliding at all, the force applied to the knuckle is increased again.
  • Bottoming the Suspension: If your suspension bottoms out, the springs and shocks are no longer absorbing any impact. The force of the impact then spreads to other parts of the car, including the knuckles.

Signs Of A Bad Steering Knuckle

Worn out Subaru steering knuckle

Image credit: backyardmech

It’s important to catch a bad steering knuckle early on. A failing steering knuckle throws your alignment out of whack and that leads to a lot of issues, such as:

  • Uneven tire wear
  • Squealing noise when turning
  • Shaking steering wheel
  • The vehicle pulling to one side instead of going straight
  • Crooked steering wheel when driving straight

Are you experiencing any of the above symptoms? Do you remember your vehicle taking a heavy impact recently? If so, your should check the steering knuckles for damage. Additionally, if your knuckle is damaged, it could completely break if it suffers another large impact.

Diagnosing A Failing Steering Knuckle In 5 Easy Steps

If you don’t want to bring your car in for an inspection, we have good news for you: it’s possible to diagnose a bad steering knuckle at home.

The most reliable way to diagnose the issue is to physically inspect each steering knuckle on your car. To do this:

  1. Lift your car. (Always use jack-stands or another safe way to support your car. Never rely on a jack alone to support a car.)
  2. Remove both wheels.
  3. Compare both knuckles. Look for cracks or bends, or other abnormalities.

Got A Broken Steering Knuckle?

If you find that one of your steering knuckles is damaged, then you need to replace it as soon as possible. It’s actually a project you can do at home. All you need are a few basic tools, an OEM replacement steering knuckle (which you can purchase online), and a trusted tutorial. Stay tuned to our next article for a comprehensive step by step guide.