Questions and Answers

Mercedes Benz 300D Rear Axles Q. Vince, 1984 Mercedes Benz 300D. The right rear axle inner boot split open. I took it to the Mercedes repair shop and they replaced the right rear axle, some bushings, and the boot. Now, only when the car is going 30 mph, does not happen at any other speed, there is a vibration similar to a wheel out of balance.

I took the car back to the Mercedes place this morning and their best guess is that the new axle is defective and they have ordered another one. They also said that another possibility is because the new axle is made differently from the original one that came with the car, and that the vibration could be because they may need to also replace the left rear axle in order to have both rear axles of the same engineering design. Meaning that mixing two different engineered axles is causing the vibration.

The vibration currently is not too bad, and I am a bit concerned about causing the dealer the additional expense of replacing the right rear axle again under repair warranty, and still have the problem, which would then lead to my paying to have the left rear axle replaced.

So, will leaving it alone and living with the minor vibration eventually lead to a major problem? Meaning that I should go ahead and have the repair done? My thoughts are to tell the dealer that I will leave it alone and ask him to give me a special price for replacing both axles later if the problem gets worse. Your thoughts?

Thanks for listening and offering advice to guys like me!!
Regards,
Ed

A. If the axle is the cause of the vibration and it is because of two different designs, then ask for a deal and get it fixed now. The vibration will put undue stress on the rear wheel bearings and the differential bearings. Neither are cheap or easy to replace on this car.

107-350-43-10 is the early version axle. The later version requires the insertion of a flange adapter into the differential and 12 allen bolt mounting hardware. The chassis breaks reflect the cars that may still be able to make use of this version, unless already converted to later style. Replaced by the 123-350-04-10 axle. Have your dealer check on this possibility also.

And don't worry about causing the dealer additional expense.