Brakes and Suspension Rear Wheel Bearing Replacement – Steel Trailing Arm Estimated reading: 5 minutes Contributors Overview This procedure guides you through replacing the rear wheel bearings on a Porsche 944 S2 with a 3.0L engine, focusing on the steel trailing arm design. Worn wheel bearings can cause noise, vibration, or play in the rear wheels, so this replacement is key to maintaining a smooth and safe ride. The process involves removing the rear wheel, hub, and old bearings, then installing new ones with proper torque and alignment. Pink and blue text represents links to additional resources, tools, parts, and partner websites. Tools Required 36mm socket 8mm Cheesehead (Triple Square) tool Metric socket set Phillips head screwdriver Jack stands Floor jack Gear puller or block of wood and hammer Seal puller Soft drift and hammer 24-inch (610mm) breaker bar (minimum, 48-inch (1220mm) recommended for stubborn nuts) 3/4-inch Drive Impact Wrench (optional, for stubborn axle nuts) Parts Required Outer bearing seal – 944 331 901 00 Inner bearing seal – 944 331 902 00 Snap ring – 944 331 903 00 Inner bearing – 944 331 904 00 Outer bearing – 944 331 905 00 Spacer tube – 944 331 906 00 Inner bearing spacer ring – 944 331 907 00 Cotter pin – 944 331 908 00 Bearing grease 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 Set the emergency brake to keep the rear wheels from turning while loosening the axle nut. Loosen the rear wheel lug nuts on one side a few turns using a 19mm wrench. Raise that side of the vehicle with a floor jack and secure it on jack stands. Remove the lug nuts and take off the rear wheel. Step 2: Remove the Axle Nut Remove the cotter pin from the axle nut using pliers. Try loosening the axle nut with a 36mm socket and a 24-inch (610mm) breaker bar. Turn counterclockwise—toward the rear for the left wheel, toward the front for the right wheel. If it moves easily, remove it and skip to Step 3. If the nut won’t budge, position the 36mm socket on the nut and attach a breaker bar (at least 24 inches (610mm), ideally 48 inches (1220mm)) parallel to the ground. Rest the handle on a jack stand, ensuring it won’t damage suspension or body parts when the car is lowered. 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 to loosen the nut. Remove the axle nut once loosened. Step 3: Disassemble the Brake and Hub Components Release the emergency brake. Remove the brake rotor retaining screws with a Phillips head screwdriver. Pull off the brake rotor. If it’s stuck, thread M8 bolts into the two threaded holes on the rotor to jack it off. Remove the parking brake pads, spreader, and brake dust guard using a 19mm wrench to undo the four hex bolts. Take off the rear hub. Disconnect the CV joint from the trailing arm using an 8mm Cheesehead tool, then hang the axle out of the way with a wire or bungee cord. Step 4: Remove the Stub Axle and Old Bearings Remove the stub axle with a gear puller or by tapping it out with a block of wood and hammer. The inner spacer ring should come with it—if it sticks to the seal, pry it off and check for scoring (replace if damaged). Use a seal puller to remove the inner and outer bearing seals. Remove the snap ring next to the inner bearing with snap ring pliers. From the outside of the trailing arm, use a soft drift and hammer to gently tap the inner bearing out, working evenly on both sides. From the inside of the trailing arm, tap the outer bearing out with the drift and hammer, keeping it even. Remove the bearing spacer tube and clean out all old grease from the trailing arm with a rag. Step 5: Install New Bearings Pack the new inner bearing (944 331 904 00) and outer bearing (944 331 905 00) with fresh bearing grease. Install the inner bearing into the trailing arm using a socket or soft-face hammer as a driver. Ensure the chamfered edge faces out (away from the center) and it goes in evenly to avoid binding. Install the snap ring (944 331 903 00) next to the inner bearing. From the outside, pack fresh grease into the trailing arm, leaving space for the spacer tube and grease expansion (don’t fill it completely). Insert the bearing spacer tube (944 331 906 00) from the outside. Tap the outer bearing into place with a socket and hammer, ensuring the chamfered edge faces out. Install the new inner bearing seal (944 331 902 00) and outer bearing seal (944 331 901 00). Step 6: Reassemble the Components Reinstall the brake dust guard, parking brake pads, and spreader, securing them with the four 19mm hex bolts. Install the stub axle, ensuring the inner spacer ring (944 331 907 00) is on it before insertion. Reattach the CV joint to the trailing arm with the 8mm Cheesehead tool. Mount the hub and thread on the axle nut. Torque it to 460 Nm (339 ft-lbs)—slightly higher than the generic 350 ft-lbs for the S2’s 3.0L setup per Porsche specs—and secure with a new cotter pin (944 331 908 00). Install the brake rotor and secure it with the Phillips head screws. Step 7: Finalize the Installation Follow this link to ensure this step – Parking Brake Adjustment – of the process is followed accurately. Install the brake caliper and pads, then pump the brake pedal a few times to build pressure. Mount the rear wheel and tighten the lug nuts by hand. Lower the vehicle from the jack stands using the floor jack. Tighten the lug nuts to 130 Nm (96 ft-lbs) with a 19mm wrench. Repeat Steps 1–7 for the other side if replacing both wheel bearings. Post Procedure Checklist Check for any play or wobble in the rear wheels by hand. Listen for unusual noises while test-driving 5 miles (8 km). Ensure the emergency brake holds the car on a slight incline. Verify brake pedal feels firm after pumping. Sources Clark’s Garage Pelican Parts Porsche 944 Workshop Manual, Volume 1 Youtube Porsche Technical Update – S2 Torque Specifications Tagged:Brakes and SuspensionWheel Bearing Rear Wheel Bearing Replacement – Steel Trailing Arm - PreviousRear Wheel Bearing Replacement – Aluminum Trailing ArmNext - Rear Wheel Bearing Replacement – Steel Trailing ArmShock Replacement
