2001-2003 Acura CL Rear Hub Assembly: Diagnosing Humming, Grinding, and Roaring Noises

Symptoms of a Failing Rear Hub Assembly

A bad wheel hub bearing usually gives you plenty of warning before a critical failure. The most common sign is noise. Listen for these specific sounds coming from the rear of your car:

• Humming or Roaring: This is the classic symptom. It's a low-pitched drone that starts faint and gets progressively louder as you increase speed. The noise is often compared to loud tire noise or a plane taking off.
• Grinding or Growling: As the bearing deteriorates further, the noise can become a rough grinding or growling sound, indicating significant internal damage. This sound also intensifies with vehicle speed.
• Clicking or Popping: While less common for a straight-line failure, clicking or popping sounds when turning can sometimes be associated with a very worn bearing.
• Noise Changes When Turning: A good way to isolate a bad bearing is to notice if the noise changes during turns. For example, when turning left, the vehicle's weight shifts to the right-side wheels. If the noise gets louder during a left turn, the right-side bearing is likely the culprit, and vice-versa.

In addition to noise, you might experience:

• Vibration: A shaky or vibrating steering wheel, or a vibration felt through the floor or seat, can be a sign of a failing hub assembly.
• ABS Light: Since the hub assembly houses the ABS tone ring, damage to the hub or excessive play can disrupt the wheel speed sensor's reading, triggering the ABS warning light on your dashboard.
🎬 Watch: How to check for bearing noise, play, and ABS issues.
• Wheel Looseness (Play): In advanced stages of failure, the wheel may feel loose. You can check for this by jacking up the rear of the car and trying to wiggle the tire from top to bottom (12-and-6 o'clock position). Any noticeable play or clunking is a definite sign of a bad bearing.
🎬 See a pro demonstrate the shake and spin diagnostic test.

Known Issues, TSBs, and Recalls

While the 2001-2003 Acura CL was a generally reliable vehicle, it is subject to a critical safety recall that all owners must be aware of.

Recalls

Takata Airbag Inflator Recall: This is a major, urgent safety recall affecting millions of vehicles, including the 2003 Acura CL. The driver-side airbag inflators, known as "Alpha" inflators, have a very high risk of rupturing during deployment, even in a minor crash. This rupture can send sharp metal fragments toward the driver, potentially causing serious injury or death. The NHTSA has issued a "Do Not Drive" warning for affected vehicles until this free repair is performed by a dealer. While this recall does not involve the hub assembly, its severity warrants mention for any owner of this vehicle.

Technical Service Bulletins (TSBs)

Searches did not reveal any Technical Service Bulletins issued specifically for the rear hub assemblies on the 2001-2003 Acura CL. Most issues are related to normal wear and tear over time and mileage.

Buying a Used Hub Assembly

For a vehicle of this age, a quality used OEM hub assembly can be a smart, cost-effective choice. New aftermarket parts can vary wildly in quality, and a low-mileage original Acura/Honda part is often made from superior materials. Here’s what to look for:

• Verify Compatibility: Ensure the part is from a 2001-2003 Acura CL or a cross-compatible Honda model. The key is that it must be a rear hub for a vehicle with ABS. The OEM part number is 42200S3MA51.
• Check for Smoothness: This is the most important test. Hold the hub and spin the bearing by hand. It should rotate smoothly and silently. If you feel any roughness, grinding, or catching, the bearing is bad.
• Inspect for Physical Damage: Check the hub flange for any signs of warping or damage from an accident. Ensure all wheel studs are present, straight, and have good threads.
• Examine the ABS Sensor Area: The hub has an integrated magnetic ring that the ABS sensor reads. Inspect this area for cracks or damage. Ensure the electrical connector for the ABS sensor (if included) is not broken or corroded.
• Consider Mileage: While condition is more important than mileage, a part from a lower-mileage vehicle is generally preferable. Bearings are wear items, so failure is more common on higher-mileage cars.

Replacement Overview & Special Procedures

Replacing the rear hub assembly on a 2001-2003 Acura CL is a feasible DIY project for someone with the right tools and mechanical experience. The hub is a bolt-on unit, which is simpler than designs that require a hydraulic press.

Key steps include:

1. Safely jack up the vehicle and remove the wheel.
2. Remove the brake caliper and caliper bracket, and hang the caliper securely to avoid straining the brake hose.
3. Remove the brake rotor. You may need to use two 8mm bolts in the threaded holes on the rotor face to push it off the hub.
4. Remove the hub dust cap and then unstake and remove the large spindle nut (axle nut). This typically requires a 32mm or 36mm socket and significant force.
5. From behind the knuckle, remove the four bolts that secure the hub assembly.
6. The hub assembly should now come off the spindle.
🎬 Watch this step-by-step walkthrough for replacing Honda and Acura rear bearings.

Torque Specs & Critical Notes

Proper torque is essential for the safety and longevity of the new bearing.

• Spindle Nut (Axle Nut) Torque: The spindle nut torque specification is critical. Sources indicate a torque value of approximately 181 Nm or 134 lb-ft. Always use a new spindle nut, as they are designed for one-time use. After torquing, the nut must be staked into the groove on the spindle to prevent it from backing off. Over- or under-torquing this nut is a primary cause of premature bearing failure.

Cost Comparison

Prices can vary based on brand, location, and supplier. The following is an estimated breakdown:

Frequently Asked Questions (FAQ)