2011-2020 Fisker Karma & Karma Revero Steering Knuckle: Diagnosing Front-End Grinding and Roaring Noises

Symptoms of a Failing Steering Knuckle or Wheel Bearing

Because this part is an assembly of the steering knuckle and the wheel hub, failure can manifest in two ways: damage to the knuckle itself from an impact, or, more commonly, failure of the internal wheel bearing. The symptoms for each are distinct.

Noises: The Most Common Symptom

A failing wheel bearing will almost always announce itself with noise. Listen for these specific sounds:

• Humming, Roaring, or Growling: This is the classic sign of a bad wheel bearing. The noise is rotational, meaning it starts as you begin to move and gets louder and higher-pitched as your speed increases. It is often compared to the sound of aggressive mud tires or a distant airplane.
• Noise Changes While Turning: A key diagnostic clue is how the noise changes when you steer. When turning, you shift the vehicle's weight onto the outside wheel. If you turn right and the noise gets quieter, the bad bearing is likely on the right (passenger) side. If you turn left and the noise gets louder, this also points to the right-side bearing 🎬 Watch: How to diagnose wheel bearings with a road test being the culprit as it is being loaded with force.
• Clicking or Snapping: A clicking or snapping sound, especially when turning, can indicate a worn wheel bearing, though it can also be a symptom of a bad CV joint.
• Clunking or Popping: A clunking noise when driving over bumps can be caused by excessive play in a completely failed bearing, or it could point to worn ball joints or other suspension components connected to the knuckle.

Steering and Handling Issues

A damaged knuckle or severely worn bearing can affect steering control and stability.

• Vehicle Pulls to One Side: A bent steering knuckle will alter the suspension geometry (camber and toe angles), causing the vehicle to pull to one side. This pull will be constant and cannot be corrected with a standard alignment.
• Vague or Loose Steering: Excessive play in the wheel bearing can translate to a feeling of looseness in the steering wheel.
• Vibration: A vibration felt in the steering wheel or through the floor, which changes with speed, can be caused by a worn bearing allowing the wheel to wobble slightly.
• Uneven Tire Wear: This is a visual sign of a bad knuckle or bearing. A bent knuckle holds the tire at an incorrect angle, causing rapid wear on the inner or outer edge.

Known Issues, TSBs, and Recalls

The Fisker Karma and Karma Revero are low-production vehicles, and as such, there are no widespread, documented patterns of steering knuckle or wheel bearing failure. Likewise, searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls or Technical Service Bulletins (TSBs) specifically related to the steering knuckles or wheel hub assemblies for either the 2011-2012 Fisker Karma or the 2017-2020 Karma Revero.

However, both vehicles have been subject to several safety recalls for other issues:

• 2012 Fisker Karma: Recalls were issued for potential coolant leaks in the high-voltage battery, faulty cooling fans that could cause a fire, and defective Takata airbag inflators.
• 2017-2020 Karma Revero: Recalls were issued for rollover sensors that were not enabled, non-compliant side-impact door brackets, incorrect driver's side mirror glass, and intermittent turn signal failure on later models.

These recalls do not affect the steering knuckle, but they highlight the importance of checking a vehicle's VIN for any outstanding safety campaigns.

Buying a Used Steering Knuckle Assembly

Due to the rarity of these vehicles, a used OEM steering knuckle assembly is often the most practical and sometimes only available replacement option. New parts are generally not available through standard retailers and must be sourced through a Karma dealership, if available at all. Here’s what to look for when buying used:

• Inspect the Knuckle Itself: The aluminum knuckle is very strong but can be cracked or bent in a collision or from a severe pothole impact. Carefully inspect the entire casting for hairline cracks, especially around the mounting points for the ball joints and tie rod. Look for any signs of impact, like scrapes or gouges.
• Check the Wheel Bearing: This is the most critical inspection. With the assembly off the car, try to turn the hub by hand. It should spin smoothly and silently. Any grinding, roughness, or catching indicates the bearing is bad and the entire assembly is not a good value, unless you plan to press in a new bearing.
• Verify No Bearing Play: Try to wiggle the hub flange. There should be absolutely zero play or wobble. If you can feel any movement, the bearing is worn out.
• Examine Mounting Surfaces: Check all the holes where other parts attach. Ensure they are round and not worn into an oval shape, which can happen if bolts were left loose. The surface where the wheel hub bolts on should be clean and flat.
• Confirm Compatibility: This part is for the front right (passenger side) on rear-wheel-drive models. While the part is shared between the 2011-2012 Fisker Karma and 2017-2020 Karma Revero, always confirm the OEM part number if possible. The number C1311222112 has been identified for the Fisker Karma.

Replacement Overview and Special Procedures

Replacing the steering knuckle assembly is a job for an experienced DIYer or a professional technician. It requires disconnecting major suspension and brake components.

General Steps:

1. Safely raise and support the vehicle and remove the wheel.
2. Remove the brake caliper and bracket, and hang them securely out of the way without stressing the brake hose. Remove the brake rotor.
3. Disconnect the ABS wheel speed sensor connector.
4. Remove the axle nut. This nut is torqued very tightly and will require a large breaker bar.
5. Separate the steering tie rod end and the upper and lower ball joints from the knuckle using a ball joint separator tool.
6. Push the axle shaft out from the back of the hub and remove the knuckle assembly from the vehicle.
🎬 Watch: A step-by-step walkthrough of a steering knuckle replacement
7. Installation is the reverse of removal.

Torque Specifications and TTY Bolts

No specific torque specs for the Fisker/Karma are publicly available. However, vehicles with similar aluminum knuckles use Torque-to-Yield (TTY) bolts, which are designed to be stretched and must be replaced once removed. These require a specific multi-stage tightening process using a torque wrench and a torque angle gauge.

For reference only, torque specs on similar vehicles can be:

• Axle Nut: Often over 200 lb-ft.
• Ball Joint Nuts: 70-120 lb-ft, sometimes with an additional angle turn.
• Caliper Bracket Bolts: 60-100 lb-ft.

Cost Comparison

Prices for these rare vehicles can vary significantly. The estimates below are based on general repair costs and the limited availability of parts.

Frequently Asked Questions