I have an 1985 300D. I've DIY'd US and Japanese cars for many years. This is my first German car and I love it.

The bottom bolts on the front shocks have what look like 12 lobes. My shop manual calls these "double hex bolts". I've never encountered them before. What are they? What kind of socket do I buy?

It's kind of funny because I'm rebuilding the suspension/steering and this is the only place I got stuck. I needed the shock out of the way so I sawzalled it off, but I still need the stump removed.

a 12point 10 mm will do the job

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

You did not say which Shop Manual you have; but, even the Mercedes manual has mistakes in the text (from translation?) or they have different names for things than we do.

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84 300D, 82 Volvo 244Gl Diesel

Thanks. I'll try that.

Unless a previous owner installed the current shock with different type of hardware like a splined head bolt or something odd like that, you should be able to remove the shock without destroying it. MBZ used a double hex(12 Pt) head bolt for a reason. To remove or install the shock you will need a 12 point closed end wrench. Access is pretty tight. Get one bolt removed and have to twist the shock into or out of place and then get the other bolt moving. Turning the bolts takes a while because you can only turn it a few degrees at a time because of clearances in that area. Again thats why the 12 Pt head on the bolt. It would be much more difficult with a 6 Pt head on the bolt.

That was my experience with it.

EddieE
"87 300SDL 325K and dead in my driveway.......again

x2

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

If you are using a 12-point wrench, it makes absolutely no difference whether the bolt head has six points or twelve. The wrench still has to move 30 degrees for the next "bite."

New front shocks come with a 12 point thin walled 10mm socket, the key being thin walled.

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83 SD

84 CD

I could not locate a thin walled socket and was able to remove and reinstall the bolts with a small 10mm open end wrench

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

That's not possible on a 12 pt. fastener. I presume that you utilized a box wrench.

Some, not all. Mine didn't.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Now you've put my mind in a geometric funk. There has to be 30 degrees of total movement, but can't half the movement be in the nut and half in the wrench? In other words, you can get increments of 15 degrees with twelve point nut and twelve point wrench but only 30 degrees with a six point nut and a twelve point wrench?
The intuitive feel of removing those bolts told me I could get much smaller increments of movement than with a 6 point bolt.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I had room on the SD to remove them with a socket and extension. Remove the outer one, Tip the shock out wards, and remove the innner one. Install inner, Compress shock and place in mounting hole, install outer bolt, faten top of shock.

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83 300SD Dark Silver Dark brown inside

Actually, you can get away with 15 degrees of rotation on a hex head (six point) bolt by alternately flipping an open-end wrench with a 15 degree offset. That's not an option with a double hex fastener, unless your box end is also offset.

Sure. Provided that the nut and wrench turn separately in opposite directions.

Much like a pound of lead seems heavier than a pound of feathers, I suppose.

Sorry, must be cost cuts, both sets of Bilstein's I bought did.

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83 SD

84 CD