Throttle Support Bolts

[jedwards]

Gentlemen,
I have been restoring the engine bay of my 1967 250SL and during the re-assembly of the throttle linkages, I noticed that the Throttle Support unit, that bolts to the inlet manifold,  has beveled edged bolt holes rather than conventional drilled holes.  Some extra effort has clearly gone into doing this, so I suspect this is not an error or an oversight.
This type of tapered shoulder suggests that the Throttle Support unit is designed to take some form of self centering bolt, in order to ensure really accurate location and alignment.  However the parts manual does not show any details of the suggested bolts and I have only even seen self-centering bolts used on wheels. 
I was therefore wondering if there is an exact location, relative to the other fixed elements of the linkage, that the Throttle Support must be aligned to.
As everything else in the linkage system must be absolutely perfect, it seems reasonable to assume that such a major piece as the the Throttle Support unit would need to be located with the same level of accuracy, but don’t know how they did the self centering.
Any suggestions?

Jeff

[mbzse]

.../...As everything else in the linkage system must be absolutely perfect, it seems reasonable to assume that such a major piece as the the Throttle Support unit would need to be located with the same level of accuracy, but don’t know how they did the self centering

Yes, the two bolts holding support 40 are bevelled, thus self-centering. Later cars had studs in the manifold and nuts to fasten the support.
The two M6 nuts that hold the other support 42 are special, conical shaped type to enable positive location as well.
/Hans in Sweden
.

[jedwards]

Thank you Hans,
That is most helpful.
Does anyone have Part numbers for these special bolts?

Jeff

[Jack Jones]

The bolt numbers are 129 990 00 01 but when I tried to price them, the number did not come up. Check Mercedes for availability.

[jedwards]

it was a simple matter get some M8 and M6 stainless steel countersunk Alan keyed bolts that worked perfectly.
They might not be original, but for now I just want things set up correctly.

Thanks so much for the help.
Jeff

[wwheeler]

The (2) M6 conical nuts for #42 that Hans was talking about are #127 990 01 51 I believe. Mine did not have them when I bought the car but have since installed them.

[Jack Jones]

There is split production where some early 250sl engines used bolts and the later 250sl and all 280sl used studs with the conical nuts.