Porsche Wheel Bearing Bolt - Genuine Porsche 99921704204

Product Information

Wheel bearings support the vehicle's weight and reduce rotational friction, located within the wheel hub/spindle. European car manufacturers typically use three types of wheel bearings: unsealed, sealed press-in, and wheel bearing/hub assemblies.

Unsealed bearings, common in pre-1990 cars, require regular greasing, while sealed bearings, used from the 1990s onward, are maintenance-free and must be replaced when worn. The most modern approach integrates the wheel bearing into the hub assembly, simplifying replacement by bolting in a new unit.

Signs of failure include a grinding noise, which worsens over time. Diagnosing involves lifting the car to check for wheel play and noise. Replacement processes differ: unsealed bearings need cleaning and proper alignment, sealed bearings require pressing out, and hub assemblies are straightforward to unbolt and replace. Correct torque application is vital for all types to prevent premature failure.

• Grinding or growling: A bad wheel bearing will first reveal itself by making a growling or grinding noise when unloaded, IE if turning right, the right side will make noise. Eventually, as it gets worse, so will the sound until it’s replaced
• Play in the wheel: With the wheel off the ground, you will detect play from a worn wheel bearing. This is because the internal bearings have worn away and are no longer perfectly tight.
• Vibration or wobble: While much less frequent, if a wheel bearing is very bad or has an excessive amount of play in it, it will cause issues with the vehicle's handling, including vibration or wobble noticeably through the steering wheel.
• Uneven Tire Wear: A faulty Wheel Bearing can adversely affect tire wear and cause uneven wear across the tire contact patch.
• ABS warning light: If you are chasing an ABS issue and you have sorted out the sensors, it’s not impossible that damage has occurred to the ABS tone ring inside of the wheel bearing. If you have a single corner fault but the ABS sensor checks out, replace the wheel bearing and in turn the tone ring.

About Genuine Porsche

The original parts used by Porsche to build your car are available as replacement parts under the “Genuine Porsche” brand. Manufactured under the direction of Porsche, expect excellent quality and a premium price since these parts are exclusively available through the Porsche Dealership network.

You may not realize this, but the parts that make up your Porsche are not necessarily manufactured by Porsche. No cause for concern, as Porsche designs the part, hires a manufacturer, and ensures its quality to you. In fact, many of these manufacturers have been making parts for Porsche for decades. In our industry these manufacturers are called OEM (Original Equipment Manufacturers), and these are often brands you recognize, including Lemforder, ZF, Sachs, Bosch, Valeo, Zimmermann, Siemens VDO, Corteco, and more. Don’t be surprised to open that Genuine Porsche parts box and find an OEM branded part inside, simply with the addition of a Porsche logo.

Be sure to keep an eye out for OE tags on our product pages to quickly identify parts coming direct from OE manufacturers. That extra bit of insight could save you some serious money while shopping! Refer to our OE Academy for further information regarding the OE/OEM tags throughout the site.