Is your Mercedes-Benz W123 300D showing its age with a noisy rear axle? Don’t worry, replacing it yourself is a manageable task. This guide, based on our experience with a 1985 300D, will walk you through the process of replacing the rear axles, ensuring your classic Benz remains smooth and quiet on the road. We noticed a clicking noise upon deceleration in our W123, a telltale sign of worn rear axles, specifically the outer boots and potentially lost oil. This prompted us to order new axles promptly.
We sourced new axles from Advanced Auto (SKU # 20870644) for an affordable $92.97 each, delivered directly to our doorstep. While at it, we also purchased new differential to axle seals, anticipating potential wear on the existing ones. However, upon disassembly, the original seals appeared to be in good condition, so we opted to keep the factory seals in place. It’s worth noting that the axles we received were manufactured in China, and their long-term performance remains to be seen.
A crucial point to highlight is the wheel hub to axle bolt spacer. The provided spacers with the new axles were longer than the originals on our W123. Caution: Carefully measure these spacers. If your W123 still has its original axles or axles that have been installed for a long time, reuse the original spacer tubes. Using the longer spacers can prevent the axle from seating correctly into the hub. We also experienced a bolt breaking during installation, reinforcing the recommendation to reuse the original Mercedes-Benz bolts whenever possible.
Step 1: Safety First – Chock the Front Wheels
Before you begin jacking up your benz w123, ensure safety by placing wheel chocks firmly under the rear of the front tires. This will prevent any accidental rolling of the vehicle during the repair process.
Step 2: Jack Up the Rear of Your W123
Position your jack under the differential to lift the rear of the Mercedes W123. A long body jack makes this task easier, allowing you to reach from the rear bumper area and lift the car safely and efficiently.
Step 3: Securely Position Jack Stands
Once the rear of your benz w123 is raised, carefully place jack stands under the subframe bushing area. This location provides a robust and secure support point. After lowering the car onto the stands, give it a firm shake to verify the stands are stable and haven’t shifted. If any movement occurs, reposition the jack stands for optimal safety before proceeding with the rear axle replacement.
Step 4: Clean the Differential Area
Since you’ll be working around the rear differential, it’s crucial to clean the area. Use a pressure washer or degreaser and a brush to remove any dirt and grime. A clean workspace makes the job easier and prevents debris from contaminating the differential. In our case, the W123 had been pressure washed recently, so a simple brushing was sufficient.
