The adapter kit allows you to use the new 12mm hardware with the older 8mm axles. If you already have 12mm hardware, your existing axles are the new type and don't need to be "adapted."

The purpose of this hardware is to hold the outside end of the axle to the wheel hub. The 12mm hardware consists of a long 12mm bolt, a large washer (looks like a fender washer, Mercedes calls it a "clamping disc"), and a tubular spacer. A photo of this setup is attached. Part #79c is the adapter for the 8mm threaded hole in the older axles, the other parts are the standard 12mm parts that you already have if you have 12mm axles.

The "clamping disc" is similar to a wavy washer, split washer, or crush washer, in that it deforms under pressure, thus keeping tension on the bolt. Mercedes recommends replacing the clamping disc but I and everyone else I've heard from have just reused them. You can either turn them over so they bend in the opposite direction or pound them flat with a hammer.

If you do need parts, I'd first try the "Buy Parts" link at the top of this page. Fastlane should have all three 12mm parts as a kit. The Fastlane guys are good at what they do and they support this forum. They should be able to get the parts for you even if they do not actually carry them in stock at all times. Since all rebuilt axles I've seen have been 12mm, that 8mm-to-12mm threaded bushing (79c) may not be easy to get, possibly a factory-only part. I'd like to hear from someone who has actually used that part.

Jeremy

Attached Thumbnails

 

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The thing is, the axle I want to put in has an 8mm hole; so I am going backwards here. I can understand if the hole is 12mm and you want to size up to use 8mm hardware, but I don't get how the reverse would work.
Or is it as simple as finding a 8mm bolt? Seems like that would need an adapter (at the bolt head) as well...

Maybe I am just over thinking (or underthinking) and missing the obvious...

Does anyone know what year those axles sizes were switched?

I did call Phil, he doesn't have that part (79c), he did give me a contact to try tomorrow...

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Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

I just went out and looked at my car and I reused the stock 8mm bolts (with a drop of 2 of Loctite). I don't know what I did with the ones that came with the axle but they were also 8mm. I do not believe that they are any special grade of bolt above what would be for normal automotive use which I believe is grade 8.8 for metric. But if in doubt or it is holding up your project you could get them from the dealer.

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84 300D, 82 Volvo 244Gl Diesel

Backwards is indeed the word. The old axle (which you have) has an 8mm threaded hole in its end. To use the new 12mm hardware (which is all M-B sells these days) you must have an 8-to-12 threaded bushing. It has 8mm male threads and 12mm female threads and allows the new 12mm bolt to screw into your 8mm hole.

You should also be able to use an 8mm bolt. Make sure you get the length correct. Both "too short" and "too long" will cause problems. The EPC says it is 85mm in length (don't know if this includes the head of the bolt or just the shaft). The part # is 123 990 32 01. Since this size was superseded by the 12mm hardware, it may be NLA -- you'll have to ask your local M-B dealer.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Thank you Jeremy for that clarification.
Now I get it. The newer 12mm must be shorter than the old 8mm to accommodate the adapter. I will see what is available and post for future folks!

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Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

The local industrial hardware store guy told me that the bolt head is not included in the length measurment.

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84 300D, 82 Volvo 244Gl Diesel

UPDATE: I am told by a tranny shop in the know that these Napas are the Chinese flavor and decided against them. I will be getting remans instead.

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Think Alternative Energy!
300CD '80 (now gone but not forgotten...)

There may be two versions of the 12mm bolt -- a short one with an 8mm adapter for use with the older axles, and a "regular" flavor to fit the newer axle with the 12mm tapped hole.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I'm one of those with the CVJ's. No problems to date (~25,000 miles, put on almost 2 years ago).

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1989 300E 144K

These axles are also available at AdvanceAuto for $88 each, a little less than your $103 each.

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Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

I logged on to Advance Auto parts and as it turns out is part of Parts America (Kregen and Checker Autp Parts and others). It showed the rebuilt axles (the $103 NAPA axles I believe he said were New ones) for my car as $99 (about 3 months ago they were $78).
Mybe there is some local or regional differance in price that makes them cost less in your area??? If you want to see:
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=A1C&MfrPartNumber=609022

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84 300D, 82 Volvo 244Gl Diesel

I was speaking on the price of the rebuilts sold by the same company (Partsamerica) may cost more out here in CA than in other states (regional). The member said they were $88 where he is I am saying out here they are $99.

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84 300D, 82 Volvo 244Gl Diesel