Rear Wheel Bearing Replacement – Aluminum Trailing Arm – 2.5L NA

Overview

This procedure outlines the steps to replace the rear wheel bearing on a Porsche 944 (8-valve engine configuration variants) with an aluminum trailing arm, applicable to both pre-1985.5 (83-85.5) and 1985.5 onwards (86-88) models. The aluminum trailing arm uses a single sealed bearing, which is more challenging to remove than the double roller bearings in steel trailing arms. This guide simplifies the process for DIY enthusiasts by avoiding the need to remove the trailing arm from the car, using a slide hammer bearing puller instead of the factory method of heating and pressing. The procedure ensures proper installation and functionality of the new bearing, critical for safe wheel operation.

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Tools Required

• Metric wrench set
• Metric socket set (including 32mm (1-1/4 inch) or 36mm (1-7/16 inch) socket for axle nut)
• Impact socket (32mm (1-1/4 inch) or 36mm (1-7/16 inch))
• Breaker bar (minimum 24 inches (610mm))
• Jack stands
• Floor jack
• 8mm cheesehead tool
• Slide hammer bearing puller
• Soft drift
• Hammer
• Phillips head screwdriver
• Torch (for heating trailing arm)
• Socket (approximately same size as new bearing for installation)

Parts Required

• Sealed wheel bearing – 999 053 054 00
• Circlip (snap ring) – N 012 425 1
• Axle nut – 928 332 333 00
• Cotter pin – N 012 645 2

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. Engage the emergency brake to stabilize the vehicle during axle nut removal.
2. Loosen the rear wheel lug nuts on one side several turns using a 19mm (3/4 inch) socket.
3. Raise the vehicle on that side using a floor jack and secure it with jack stands.
4. Remove the lug nuts and the rear wheel.

Step 2: Remove the Axle Nut

5. Remove the cotter pin from the axle nut using pliers.
6. Attempt to loosen the axle nut using a 32mm (1-1/4 inch) or 36mm (1-7/16 inch) impact socket (depending on your model) and a breaker bar at least 24 inches (610mm) long.

If the nut loosens easily:

• Remove the axle nut and proceed to Step 3.

If the nut does not loosen:

• Position the impact socket on the axle nut and attach the breaker bar parallel to the ground, resting the handle on a jack stand. For the left wheel, point the breaker bar toward the rear of the car; for the right wheel, point it toward the front.

• Ensure the breaker bar and jack stand are positioned to avoid damaging suspension components or bodywork.

• Slowly lower the floor jack until the vehicle’s weight breaks the axle nut free.

If this still does not work:

• Use a 3/4 inch drive impact wrench or take the vehicle to a shop with one to loosen the nut.

Step 3: Remove Brake Components

7. Remove the rear brake pads and caliper using a 17mm (11/16 inch) wrench, securing the caliper out of the way without stressing the brake line.
8. Release the emergency brake.
9. Remove the brake rotor retaining screws using a Phillips head screwdriver.
10. Remove the brake rotor. If stuck, thread M8 bolts into the rotor’s two threaded holes to jack it off the hub.

Step 4: Disconnect the Axle

11. Using an 8mm cheesehead tool, disconnect the CV joint from the transaxle.
12. Pull the axle out of the trailing arm and set it aside.

Step 5: Remove the Hub and Bearing

13. Using a soft drift and hammer from the inside of the trailing arm, drive the rear hub out of the trailing arm.
14. Remove the parking brake shoes, spreader arm, and brake dust guard.
15. Remove the circlip next to the wheel bearing using snap ring pliers.
16. Heat the trailing arm around the wheel bearing to 120–150°C (250–300°F) using a torch to ease removal.
17. Using a slide hammer bearing puller from the outside of the trailing arm, pull the wheel bearing out.

Step 6: Install the New Bearing

18. Apply a light coating of grease to the inside of the trailing arm bearing surface to ease installation.
19. Using a hammer and a socket approximately the same size as the new bearing, tap the new bearing (999 053 054 00) into the trailing arm, ensuring it goes in evenly to prevent binding.
20. Install the new circlip (N 012 425 1) next to the bearing using snap ring pliers.

Step 7: Reassemble Components

21. Install the brake dust guard, parking brake shoes, and spreader arm.
22. Install the rear hub into the trailing arm.
23. Install the axle and new axle nut (928 332 333 00). Torque the axle nut to 500 Nm (368 ft-lbs) using a torque wrench.
24. Install the brake rotor and secure it with the Phillips head screws.
25. Install the brake caliper and pads, ensuring proper alignment.
26. Pump the brake pedal to restore brake pressure before driving.

Step 8: Adjust Parking Brake and Finalize

27. Follow this link to ensure this step – Parking Brake Adjustment – of the process is followed accurately.
28. Install the rear wheel and tighten the lug nuts to 130 Nm (96 ft-lbs).
29. Lower the vehicle from the floor jack.
30. Insert a new cotter pin (N 012 645 2) through the axle nut to secure it.
31. Repeat Steps 1–8 for the other side if replacing both wheel bearings.

Post Procedure Checklist

• Verify the axle nut is torqued to 500 Nm (368 ft-lbs).
• Ensure the brake pedal feels firm after pumping.
• Check that the parking brake holds the vehicle securely after adjustment.
• Inspect for any unusual noises or vibrations while test-driving 5 miles (8 km).
• Confirm no brake drag or wheel play exists.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube