W123 Mercedes CV Boots and Axles

Cracked CV boots are nothing new, but replacing them can be costly, and the axles might not warrant the time or money if the milage is high enough or the boots have cracked. Reconditioning an axle in uncertain condition will likely not serve you well in the long run and could easily lead you to spend even more money having to install new axles in the end. Instead, consider replacing the axles. Wait! It's not as hard as it sounds!

Mercedes-Benz used two types of axles, homokinetic and annular. According to Mercedes, the W123 could have either axle depending on the year it was built so make sure you check your vin and the axle itself before you make a purchase. Regardless, if you are in need of new CV boots with original high milage axles, this would be the time to move ahead with replacing the entire unit.  If your chassis is already fitted with annular, the job will be that much simpler. 

So what's the difference? What's better? Why convert? Who cares?

The difference between homokinetic and annular is how it functions, and that is a subject we will not cover here, but we will cover how they differ with regard to installation.

The following image shows the Mercedes-Benz OE annular axle along side the aftermarket axle that is a cross between an annular and a homokinetic based on the one piece design. The Mercedes axle as you can see requires a "flange" sitting separate from the axle which will be permanently installed in the differential making for a much simpler repair or replacement in the future.

At this point you have several options for this job. First, you can purchase a rear axle flange (needed for conversion from homokinetic to annular) and annular axle from Mercedes. Second option, purchase an aftermarket or refurbished homokinetic unit. Third option, install an aftermarket unit.

Is one better than another? If you are purchasing MB annular axles (homokinetic is no longer made by Mercedes), you are getting an excellent product, the same quality that has probably lasted 40 plus years. Should you go the direction of aftermarket or rebuilt, you run a good risk of noise, vibration and a much shorter life span.

After much research, I purchased what I believed to be the best aftermarket axle on the market, and unfortunately had my slight bubble of hope burst by what I saw, felt and heard. In fairness, it didn't appear all bad, but nothing I would want on my car. Ultimately I wanted to see if a $160 aftermarket axle could by chance prove good enough, and sadly it did not. Most often the old adage holds true, "you get what you pay for".

In brief, the new aftermarket axle right out of the box had a tremendous amount of play in each joint, along with internal components that already clicked and clacked against each other while being pivoted by hand. The original Mercedes axle however, was nearly impossible to move by hand, and no internals could be heard contacting each other what so ever. Several other observations with the aftermarket: the boots were manufactured of substantially thinner rubber, and one of the boots was not installed neatly. In addition the shaft was substantially thicker than the MB unit leading me to believe they have used an inferior steel and need the extra diameter for structural integrity. There were also numerous other areas that lacked the detailing where seals were to seat etc. 

These multiple deficiencies did not build my confidence in the product as a whole and further more I did not want to risk introducing a potentially inferior component into a differential that I know is in immaculate condition. 

On the flip side, no matter which direction you decide to go, installing either axle style is not difficult, but requires more work to change out the homokinetic / aftermarket style should the time come again. As stated previously, the annular is very straight forward after the MB flange is fitted.

Coming Up:  Step-by-Step removal and installation of the rear axles.

Retro W123 Mercedes Factory Window Sticker, Booklets

It's not often that one gets to purchase a car with most all of the original paper work, manuals, etc. I was grateful to have had the opportunity to acquire my 1981 Mercedes 240D from the original owners of 34 years who not only kept the car in near perfect condition, but included most all the original near perfect documentation from the factory.

Liking automotive history and the stories that go along with cars got me thinking that as younger generations begin to collect cars, many might not have access to some of the original factory pieces. In as much, many old enough to have known these cars from the beginning may have all but forgotten just how it was.

The following I compiled as both a historical perspective, and for some a journey down memory lane. You will see the original books (and page examples in the books) manuals,  inserts and factory invoice (window sticker), and the touch-up paint that came with my 1981 240D. From what I have been told, the only piece that is missing is the service log booklet.

Manufacturer invoice "window sticker"

This would also have been on the window adjacent to the above window sticker

Original envelope mailed June 16, 1981 to owners after purchase from Mercedes-Benz U.S.A. in New Jersey. The following 8 documents were in this envelope.  

Document 1 from envelope

Document 1 example of inside pages

Document 2 from envelope

Document 2 example of inside pages

Document 3 from envelope

Document 4 from envelope

Backside of document 4 above

Document 5 from envelope

Document 5 example of inside pages

Document 6 from envelope

Document 7 from envelope

Document 8 from envelope

Owner's Manual and other glovebox documents that came with car at time of purchase

1981 240D, 300D, 300CD Mercedes-Benz owner's manual

1981 240D, 300D, 300CD Mercedes-Benz owner's manual inside pages

1981 Mercedes U.S.A. diesel fuel guide dealer location booklet

1981 Mercedes U.S.A. diesel fuel guide booklet inside pages

1981 Mercedes North America FM Stereo Radio usage booklet

1981 Mercedes North America FM Stereo Radio usage booklet inside pages

This 1981 Mercedes Consumer Information booklet is applicable to the 240D as well and was required by U.S.A. Federal law on stopping abilities etc. It appears Mercedes was able to use this with all W123 models as the information was applicable throughout the model range

This 1981 Mercedes Consumer Information booklet inside pages

Hang tag on cruise control stalk still complete with original string

Tire information card. This was found under the original spare tire from 1981

This sticker is located on the inside of trunk lid

Touch-up paint

This is a photo of the Norman Scott, Inc. Houston, TX dealership where my W123 was purchased. Image appears to be from the 70's. From this photo the dealer did not sell Mercedes-Benz at the time, and evidently did not sell Mercedes for very long. Research shows that Norman Scott, Inc. primarily sold Porsche and Audi for most of its existence along with several other dealerships that sold other marques.