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1975 450 SEL restoration

Started by McGhee5120, 04 July 2022, 01:34 PM


  I've recently came into possession of a one owner 1975 450 SEL (W116 I believe). It has 35,000 miles on it and in great condition in appearance. It also has a very interesting history.

  My best guess is it was garage parked sometime before 2011 with a 1/4 tank of gasoline still in it.

  Almost all of the gas has evaporated so what was left had the consistency of syrup and the worst bad gas smell I've experienced. Gas tank is now clean, fuel pump and fuel gauge sending unit were both beyond repair which is where my problems started.

  I am a retired mechanic but I've never touched a Mercedes much less worked on one. I understand all hoses, belts, fuel lines, and vacuum hoses will need replacing. I finally gave up finding the exact fuel pump and settled on a Bosh with the same specs but a different output direction. Straight out instead of 90 (degrees) Still haven't found the exact tank sending unit at all.
 Is replacing these items with exact cloth covered hoses and clamps, smooth rubber hoses, silicone hoses, ect necessary to maintain the cars originality?

  The car came with Blue Velour carpet and seats having very large blue corduroy style upholstery material. I cant seem to find this anywhere in a 1975 Mercedes at all, I did see it in a few early 80s pictures. On the back seat the padding has turned to dust and the cloth was perfect till I sat in it and it was like tissue paper and now destroyed, front seats are perfect. Called the local Mercedes and they said I couldn't get them or the material to recover them, and replacement with leather would be the best option. Due to it's history I'd really like to finish this car as it was delivered. I'm about ready to start ordering parts if I can find them.   

 I joined yesterday and was told was the best place for me to get the information needed on this W116. I did get a nice recommendation on a book on how to tune the Kjet fuel injection system today.  Hopefully the fuel system won't give me too much trouble when I get to that point. Well, I had several pictures to add but it appears they are too large.

 Any help would be greatly appreciated



Hello welcome ,
I think that you have D-jetronic fuel injection on your car based on the year 1975 and the fuel pump with the 90 degrees outlet you discribe , resize your pics to a smaller size and try again to insert them in to your post , you have Pullman velour interior the best looking interior to have in a W116 (in my opinion)



Blue velours:

I think the fabric is currently not available, but is being remade in the next year or so.

Were all pretty good here about finding parts, Let us know what you are looking for.
on the right side is seat materials catalog.

'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,

Jan S

Hallo and welcome!

What a great car you have - a one owner low mileage is not common these days.

I also believe your car has d-jet. I replaced the entire k-jet fuel assembly 1-2 years ago. All parts readily available.

I bought good quality fuel hoses, some original MB, and some had an inner coating that made them resistant to ethanol.

Velour is fantastic. Too bad you need to replace it with leather.

Please add some pic! 
1975-mod W116 450 SE with 6.9 engine


Fuel sender.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,




Thank you all for responding this.
Sorry about the duplication on the pics not sure how I did that.

RUMB: I might be adding more work than necessary looking for the exact part number?  My tank sender is a two piece using a separate nut to secure it in the tank and a different part number on the sender itself. 21/302  817/10/1  3 83
This unit would save me quite a lot of money if it'll work?

johnnyw116 and Jan S:  I'm not sure how to distinguish between the K-jet and D-jet yet, but I'm adding a pic of the engine and hopefully you can tell.



1977 450 SEL 6.9 - Astralsilber



Lovely car! I'm sorting out the DJet on my 75 as well.

That rear seat will be your biggest headache unfortunately. There is this set ( on ebay in Germany that you may want to consider. The cover is ratty but it could be a matching stopgap until the material is available again. The bigger thing is that it looks to have good seat springs. If yours are rusted away, buying a good used set from Europe is the best current option because these cars are very thin on the ground in wrecking yards and such. You might also need to buy new rear seat pads. I believe was the best place to get them but I think GAHH might also carry them. I was very lucky to find a parts car with immaculate rear seat frames and pads that I transferred into mine.
75 450SEL
80 300SD- ZF8 OM606 superturbo
83 300D- 6-speed M111 Kompressor
84 300D- 5-speed OM617
92 300D- 722.6 OM603 3.5
93 190E 2.6 Sportline LE x2- 6-speed M111 turbo, 3.0 M103
02 C320 Wagon
03 Sprinter 2500
06 E500 4Matic Wagon


Definitely Djet. I believe if manufactured after June/July the first of the Kjet came out. Mine is a Djet (March 1975).
What this country needs are more unemployed politicians.
Edward Langley,  Artist (1928-1995)


Quote from: Pete49 on 05 July 2022, 10:01 PMDefinitely Djet. I believe if manufactured after June/July the first of the Kjet came out. Mine is a Djet (March 1975).
I believe the same that mid/late 1975 the k-jetronic came in , and around that date also the first 6.9 came out and i also think that the 6.9 was the first k-jetronic equipped W116 , i owned in the past an 1975 450SE with k-jetronic but i cant remember from which month it was


I did buy a used tank sending unit on eBay which should arrive by the end of the month, and with that I'll be ready to replace the fuel tank back in the car.  The new fuel pump came with two check valves one I'm assuming to be mounted on the pressure side of the pump but I've found no check valves in the old pump assembly unless there is a check valve inside the old pump?

  On the third pic I'm including, this was mounted between the suction side of the fuel pump and the fuel tank.  Does anyone know what it is, and what it does? Is this something that must be replaced or just a good cleaning and paint?


Yes the old pump has the valve inside that opens up at 3 Bar towards the fuel filter, and on the third pic that is an fuel damper it has some sort of noise reducing fuction ? a cleanup and some paint will do , i had recent the same problem that i could not find the original d-jetronic fuel pump (mine was leaking) so i used an Nissan 17011-P7211 fuel pump these are identical to our old NLA D-jetronic fuel pumps .
You can put your fuel tank back and install the sender unit later iff you want becouse you have acces to the fuel sender unit when you take the first aid kit out


That is a damper within the fuel system functioning I believe to absorb the fuel pulsating
as a result of the pump function thus evening out the system pressure.
1973 350SE