Firewall Throttle Linkage 84 300D
 

I was having an inconsistent Accelerator Pedal Movement and inconsistent acceleration. Sometimes I floored the Accelerator Pedal and got poorer then normal acceleration other times it was normal.

I took a guess it was the Firewall throttle linkage as I know the linkages are otherwise OK and my inspection of the Accelerator Pedal inside uncovered nothing wrong.

You can see from the pictures that there is a collar that protrudes through the metal part that cracked off the old one allowing it to move around and at the same time there was too much play inside where the steel shaft goes.

While the rubber part clan also delaminate in my case that was OK.

Replacing it fixed the issue.

I used a genuine Mercedes Part name on the package is Support, Throttle Link part number A 123 400 13 40 however the A is normally not used when you go to parts places.

Also different years and models may use a different part as I believe there is 3 types of linkage setups on W123s.

A part that is probably going to age out with time and use. May become a NLA part down the road.

Plastics and rubber survive better in the more northern latitudes. Keeping metal from returning to nature requires some effort though.

I paid about $52 for it and the shipping was free. And there was a lot of them for sale.

I have a spare one just in case.

Throttle Linkage Bushing
 

You were very wise to buy from M-B as the cheaper ones tend to have that white plastic part fail in a few short years .

The 240D's have a slightly different version, I didn't realize there were three types, yikes .

mine was about 2 accelerations away from falling apart entirely when I noticed it. Was able to source an MB from local indy next dat for about 50 something. Def weak point in the linkage, IMO.

I am thinking if your Motor Mounts are collapsed and or the Engine is rocking back and fort for some other reason that it puts more strain on that part.

Here is 2 pics from our other members showing the same type of failure. One of them looks newish.

The big black rubber isolator block often comes un bonded from the metal plates, I've seen some ingenious fixes for that .

The rubber separated in my 1985 300D years ago. I wrapped it w/ steel wire, which worked fine. I doubt the rubber helps much in decoupling engine vibrations from the fuel pedal, which I assume is its purpose. I eventually replaced w/ a junkyard one, plus grabbed a spare later. One car I pulled one from was an earlier ~1970's M-B so appears many cars used that basic part. My W123's have 2 holes on the firewall to install it, only one of which fits. I expect the other mounting hole is for gas W123's.

Throttle Isolator Failures
 

Yes ~

I've seen a few with screws installed that went clear through and bit into the far side metal plate, both machine screws with nuts and some with self tapping screws .

I've also seen the round white (usually yellow with age) bushing replaced with wine corks and other assorted bodge repairs .

When I noticed the rubber beginning to part I used a zip tie very snugly, it held until I got my new part from the Classic Center too bad I can't usually post pictures here, it was a simple .05 cent on the road repair .

vwnate, so i've been informed my 82 240D is in need of this part and i noticed you said the 240Ds have a slightly different version. Is there any way i can tell if I've found the right one as i begin the search?
(i'm also very much a novice with very limited understanding)

It's just Nate thankyouverymuch :P .

Maybe post a picture of what you need ? .

I replaced the various wear parts in my 1982 240D with automatic, it took me a bit of searching to find the correct part .

Do you happen to have this part number for the 91 W126 350SDL? My rubber piece sheared in half and my star unit is getting repaired and most of the online epc are giving me very limited results.

I have never seen one so I cannot visualize it.

There used to be Russian part sites that are in English where you can look part numbers up. Pelican parts may even have the part umber.

Do a google search 'Russian Mercedes parts sites'.

So it looks pretty similar to the 123 setup. Oddly the P/N on the bushing is 1263005225 but I can't find that number anywhere, not even on the online EPC's or mercs own dealer network part sites.



I did however find PN 1263004625 which APPEARS to be the same part and fits. can anyone cross reference previous PN to see if the first number was replaced by the latter?


I have a sneaking suspicion that it's probably even the same part as the 123 part number piece... Don't mind my jury rig to get home after the rubber sheared in half..