Rear Wheel Bearing Replacement – Aluminum Trailing Arm

Overview

This guide walks you through replacing the rear wheel bearing on the aluminum trailing arm of a Porsche 944 with a 16v engine. The wheel bearing keeps the rear wheel spinning smoothly, and replacing it is essential when it wears out, causing noise or play in the wheel. Unlike steel trailing arms, the 944 uses a single sealed bearing, which can be tricky to remove but doesn’t require removing the entire trailing arm from the car. This method uses a slide hammer puller instead of the factory’s heat-and-press approach, making it more DIY-friendly.

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Tools Required

• Metric wrench set
• Metric socket set (including 32mm or 36mm impact socket for axle nut)
• Jack stands
• Floor jack
• 8mm cheesehead tool
• Slide hammer bearing puller
• Soft drift and hammer
• Phillips head screwdriver
• Breaker bar (at least 24 inches (610mm), 48 inches (1219mm) recommended for stubborn nuts)
• Torch (optional, for heating the trailing arm)
• 3/4 inch drive impact wrench (optional, if breaker bar fails)

Parts Required

• Sealed rear wheel bearing – 944 331 901 00
• Circlip (snap ring) – 999 085 007 02
• Axle nut (self-locking) – 928 332 257 03
• Cotter pin (if not reusable)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Parking Brake Adjustment

Step-by-Step Procedure

Step 1: Prepare the Vehicle

1. Set the emergency brake to lock the rear wheels and help with axle nut removal.
2. Loosen the rear wheel lug nuts on one side a few turns using a 19mm wrench.
3. Raise that side of the vehicle with a floor jack and secure it on jack stands.
4. Remove the lug nuts and take off the rear wheel.

Step 2: Remove the Axle Nut

5. Remove the cotter pin from the axle nut using pliers.
6. Try loosening the axle nut with a 32mm or 36mm impact socket and a breaker bar (at least 24 inches (610mm)). Turn counterclockwise—toward the rear for the left wheel, toward the front for the right. If it comes off easily, move to Step 3.
7. If the nut won’t budge, position the socket and breaker bar parallel to the ground, resting the handle on a jack stand. Ensure it won’t damage suspension or body parts when the car is lowered.
8. Slowly lower the floor jack until the car’s weight breaks the nut free. If this fails, use a 3/4 inch drive impact wrench or take the car to a shop with one.
9. Remove the axle nut and washer, setting them aside.

Step 3: Disassemble the Brake and Hub Components

10. Remove the rear brake pads and caliper. Hang the caliper with a wire to avoid straining the brake line.
11. Release the emergency brake.
12. Remove the brake rotor retaining screws with a Phillips head screwdriver.
13. Pull off the rotor. If it’s stuck, thread M8 bolts into the rotor’s two threaded holes to jack it off the hub.
14. Using an 8mm cheesehead tool, disconnect the CV joint from the transaxle, pull the axle out of the trailing arm, and set it aside.
15. From the inside of the trailing arm, use a soft drift and hammer to drive the rear hub out of the trailing arm.
16. Remove the parking brake shoes, spreader arm, and brake dust guard.

Step 4: Remove the Old Wheel Bearing

17. Remove the circlip (snap ring) next to the wheel bearing with snap ring pliers.
18. (Optional) Heat the trailing arm around the bearing with a torch to 120–150°C (250–300°F) to make removal easier.
19. From the outside of the trailing arm, use a slide hammer bearing puller to pull the old bearing out.

Step 5: Install the New Wheel Bearing

20. Apply a light coating of grease to the inside of the trailing arm’s bearing surface to ease installation.
21. Using a hammer and a socket matching the new bearing’s outer diameter, tap the new bearing (944 331 901 00) into the trailing arm evenly to avoid binding.
22. Install a new circlip (999 085 007 02) next to the bearing.

Step 6: Reassemble the Components

23. Reinstall the brake dust guard, parking brake shoes, and spreader arm.
24. Slide the rear hub back into the trailing arm.
25. Reinstall the axle and secure it with a new axle nut (928 332 257 03). Torque to 500 Nm (368 ft-lbs) using a torque wrench.
26. Insert a new cotter pin (if needed) to lock the axle nut.
27. Reinstall the brake rotor and secure it with the Phillips head screws.
28. Reinstall the brake caliper and pads. Pump the brake pedal several times to restore pressure.
29. Follow this link to ensure this step – Parking Brake Adjustment – of the process is followed accurately.

Step 7: Finish Up

30. Reinstall the rear wheel and tighten the lug nuts by hand.
31. Lower the vehicle from the jack stands using the floor jack.
32. Tighten the lug nuts to 130 Nm (96 ft-lbs) in a star pattern with a torque wrench.
33. Repeat the entire process for the other side if needed.

Post Procedure Checklist

• Check that the wheel spins freely with no grinding or excessive play.
• Ensure the brake pedal feels firm after pumping.
• Verify the parking brake holds the car on a slight incline.
• Inspect for any grease leaks around the new bearing.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube