I strongly advise consulting a repair manual specific to your year and model Mazda MX3. This manual will provide precise details, torque specifications, and diagrams crucial for successful completion. Generic instructions are insufficient and can lead to damage or injury.
However, here's a *general* overview of the steps involved. Remember, this is NOT a substitute for a proper repair manual:
1. Preparation:
* Safety First: Use jack stands, not just a jack, to support the vehicle safely. Disconnect the negative battery terminal.
* Gather Tools: You'll need jack and jack stands, lug wrench, wheel chocks, socket set (metric), a bearing press (or puller and press), a hammer (possibly a slide hammer), penetrating oil, grease, new wheel bearing, and possibly a new ABS sensor (depending on the bearing location and damage). A torque wrench is essential.
* Raise and Secure: Safely raise the vehicle and secure it with jack stands. Remove the wheel.
2. Removing the Hub Assembly:
* Disconnect Brake Caliper: Carefully remove the brake caliper and hang it securely out of the way. You might need to compress the caliper piston.
* Disconnect ABS Sensor (if applicable): Carefully disconnect the ABS sensor wire.
* Remove the Rotor: Remove the brake rotor. It may require some persuasion; use a rubber mallet to avoid damage.
* Remove the cotter pin and castle nut: This secures the hub to the axle.
* Remove any other retaining components: This will vary depending on your MX3 model; consult your repair manual.
* Separate the Hub Assembly: Carefully remove the hub assembly from the upright. This might involve removing several bolts or using a puller depending on your specific model.
3. Bearing Removal and Installation:
* Press Out the Old Bearing: This is where a bearing press is crucial. Using a hammer and punch can easily damage the hub. The press will allow you to carefully remove the bearing from the hub.
* Clean the Hub: Thoroughly clean the hub to remove any old grease or debris.
* Press In the New Bearing: Use the bearing press to carefully press the new bearing into the hub. Make sure it's seated correctly and evenly.
4. Reassembly:
* Reinstall the Hub Assembly: Reverse the removal process, carefully installing the hub assembly onto the upright.
* Reinstall the Rotor, Caliper, and Wheel: Ensure everything is correctly aligned and tightened to the manufacturer's specifications (from your repair manual). Use a torque wrench!
* Torque Specifications: Pay close attention to torque specifications for all bolts and nuts. Over-tightening can damage components.
* Bleed Brakes (if necessary): If you disconnected the brake line, you'll need to bleed the brakes to remove any air in the system.
5. Test and Verify:
* Test Drive: After reassembly, carefully test drive the vehicle to ensure the new bearing is functioning correctly. Listen for any unusual noises.
Disclaimer: This is a general overview and might not apply to your specific Mazda MX3 year and model. Incorrectly replacing a wheel bearing can lead to serious damage to your vehicle and potentially dangerous driving conditions. If you are not comfortable performing this repair yourself, please take your vehicle to a qualified mechanic. Using a repair manual specific to your vehicle is crucial for a successful and safe repair.
