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1979 300sd throttle linkage quesiton.

Started by geospine, 07 March 2015, 02:12 AM


So I was poking around under the hood today, troubleshooting a recently developed engine power dilemma...
Engine revs and the turbo spools when in neutral, but when engaged the engine lacks power and can't climb a hill for beans.
I got to looking at the throttle linkage and it looks to me like I'm missing something.
Does anybody know what this piece is supposed to mount to?
The bracket my finger is touching is loose and will sag an inch our two when not being held.
The rod connects back to some linkage entering the firewall in front of the driver.


Hi geospine,

I don't know if you fixed it already, but the end of the shaft on the throttle linkage you are touching in your photo goes into the hole in the black rubber piece on the STOP lever linkage and the "bracket" goes below the rubber piece.

If there was enough play in the linkage to allow the shaft to fall out of the rubber piece, then I suspect the plastic ball and socket joint in the firewall at the other end of the linkage might have broken into pieces. 

Attached are photos of the throttle setup on my 1978 W116 300SD.

Please post and let us know if this fixes your problem.
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022


Thanks Alec300sd!

That worked!
The bracket fits around a plastic peg on the bottom of that black plastic bushing and the rod fits directly into the hole in the bushing.
It didn't look like it would fit because of the peg but thanks to your photo I got it put back together.
The plastic receiver on the firewall was not broken, but there is quite a bit of play, by design apparently, when that rod comes loose.
I will look into a more secure way to fasten that union together, but it did resolve the engine power dilemma!

I was hoping it was something simple like that.
Thanks again for your help!
I will upload a detailed picture later this evening.



Glad that my pictures were helpful and that nothing was broken.

Hopefully the fix is permanent. If it gets loose again check out the Factory Service Manual (FSM = the second sticky on this Tech Forum).

If any throttle adjustments are needed, the FSM has all the procedures under Main Function Group 30 Throttle Control in the Engine Manual section.  Their photos are black and white and quite a bit grainy. Sometimes its hard to tell where on the car the part is actually located.

Anytime I want to tackle any system I am not completely comfortable with (like climate control), I read the FSM and search the various MB forums beforehand.
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022


Here is a close up of the bracket.

Thanks again Alec300SD!
...and everyone,
this site is the best w116 resource out there!


Can anyone tell me where i can buy this lever? My ruber shred and i can fix it
Thank you


I just had the rubber bushing on the stop lever break in half. And the 30 section of the Engine Shop Manual will not load. (every other section does load & it doesn't matter which flavor browser). I've found the lever without bushing on eB but can't find any reference to this bushing (part number) anywhere. The rod from the firewall sits inside this bushing at the stop lever. Does anyone have a schematic that shows the part number for this bushing. I need to start my search, cant drive the car without it. Or, does someone have one they can part with. Thanks. BTW, 1980 300SD.