1973 280SEL 4.5 Injector Seal - Wrong Size?

[JeffreyNMemphis]

Hello Friends,

I am right in the middle of installing new injector seals on my 1973 280SEL 4.5. The injector is the 036.

The new seal is not the same as the one I removed from the injector port. Please take a look at my photo and tell me what you think? The seal I removed looks like an original 35-year old bit. Did Mercedes change the design? The diameter of the new seal is larger, and the hole that the pintal would go into is smaller.

Thank you in advance!

Jeffrey

[JeffreyNMemphis]

The diameter of the new seal is about the size of a nickel, the diameter of the old seal is about the size of a dime. Can anyone add their two cents? The new one does not fit, so I think the parts house made a mistake.

I will go get some new seals tomorrow...

[Graham]

Originally Posted by JeffreyNMemphis

Hello Friends,

I am right in the middle of installing new injector seals on my 1973 280SEL 4.5. The injector is the 036.

The new seal is not the same as the one I removed from the injector port. Please take a look at my photo and tell me what you think? The seal I removed looks like an original 35-year old bit. Did Mercedes change the design? The diameter of the new seal is larger, and the hole that the pintal would go into is smaller.

Thank you in advance!

Jeffrey

I think there are two types - One for California cars and one for Fed. The shop manual shows the two types on page 07.4.1 11-215/3.

I just ordered mine for the same injectors - I ordered part number 1160780473. Hope it is correct!

[Gurunutkins]

I have not worked on a 280sel in particular, but lots of the 116 and 117 engines in other versions of the car and all of them have had nylon injector holders in the head. Someone may well correct me but there should be an insert that goes into the hole you are looking at then the injector and the top hat or the green oring seals them into the nylon holder. they just pull out and tap in. I have included some pictures. I have bigger pictures if you want them. normally you just tap them into the head but I always put O2 sensor safe rtv sealant on them. I'm anal about vacuum leaks on these engines.
let me know if the 280 sel is different
cheers
barri

[Gurunutkins]

sorry for misleading you and hopefully you havent read the item above yet but what you have is entirely correct. the info above is only for cars with the green oring. my 116 also has top hat seals that look just like yours and they do go straight into the head, seal first then push the injector into the seal. Dont know what i was thinking last night, probably the 3 glasses of wine talking! sorry again what you have is correct and will work on your head.
cheers
barri

[Graham]

Originally Posted by Gurunutkins

sorry for misleading you and hopefully you havent read the item above yet but what you have is entirely correct. the info above is only for cars with the green oring. my 116 also has top hat seals that look just like yours and they do go straight into the head, seal first then push the injector into the seal. Dont know what i was thinking last night, probably the 3 glasses of wine talking! sorry again what you have is correct and will work on your head.
cheers
barri

barri - I looked up the fuel injector holder part number 1160780083 in your picture - It is used for 982 engines with number from 019517- and for 983 engines with numbers 013741- .

But Jeffrey's problem, I think was that the top hat seals he bought were larger in size than the originals. The injectors I have here are out of a '72 280se and they have the small top-hats. But, I only see one part number and it 1160780473 for that type of seal.

As you know, the California cars used the green o-ring seal along with the nylon older/insulator and epc says that part is 1160780773 and is for fed engines from 026126- and California 019517- so it seems MB may have adopted that type for all later cars?

Nothing is easy...

[JeffreyNMemphis]

The larger seal is bigger than the hole in the head. And, the pintal will not fit as the original did...

Update: I ordered the correct seals, will be here afternoon.

[JeffreyNMemphis]

Thank you all for your experience and hindsight (my foresight!)

The old injector seals were badly decayed. No wonder fuel (and pressure) was leaking.

The tip about using the shop vac with a small wand attachment was immensely helpful. I vacuumed immediately after removing the injectors, and then immediately again when I got the old seal out.

Part of the crumbled seal fell down into hole. Is my engine going to explode?

I took the car out for a test drive. The engine seems more balanced and strong. I need to check the fuel pressure with a gauge.

[Graham]

Originally Posted by JeffreyNMemphis

Thank you all for your experience and hindsight (my foresight!)

The old injector seals were badly decayed. No wonder fuel (and pressure) was leaking.

Jeffrey - what was the number of the seal that did work with the 036 injector on your '73 model? Might help others get the right part.

Did you buy it from dealer or aftermarket?

I get mine in morning - hopefully I gave them correct numbers!

The fuel leaks are usually from the hose connections - The ones on the spare injectors I am working on are very brittle and I can see some were changed. I changed all the hoses on my car but I will probably need to do it again when I swap the injectors.Common problem especially with the original crimped on hoses.

And seal leaks - that would cause a vacuum leak - Again a common problem on these cars and so many places they can leak. I thought I had a leak (high idle speed) but it turned out to just be a sticking Aux Air Valve. Claned it up, but it still sticks a bit and bypasses air (in effect a vacuum leak)

By the way - Those covers look great - I must get some of that polish!

[JeffreyNMemphis]

Graham,

The seal that does not fit is 116 078 08 73 (1976 on). I bought these on Ebay. The guy was advertising these for 1973 280SEL 4.5 without giving a part number. It is a good part, just doesn't fit my car.

The correct seal part number is 116 078 04 73 (up to 1976). I bought these from a local independent import car repair shop. They didn't look identical to the original, but they are the right size and the fit seemed snug and correct.

The whole job was actually pretty easy, but very dirty because of my leaking valve cover gaskets and the seals themselves leaking fuel.

Last January I had all of the fuel lines replaced. I was in the middle of my move from Memphis to Houston and didn't have tools to do it myself. If I force myself to remember how much I paid to have it done, I might start to vomit. It is a super easy job to do involving about 36 inches of 160 psi fuel line and sixteen small hose clamps.

I am glad to have it all completely sorted out. The thought of my car catching on fire has been one of those nagging reminders of the risk that I was putting off dealing with.

I hope the newbies that buy these cars search the forum for these discussions and address the fuel lines first. It is an easy job. I see too many cars on Ebay with fire damaged engine compartments/

[Graham]

Picked up my parts at the dealer today. Everything looks fine. Only thing I regret, is not buying a few extra pintle caps, just in case I break one!

I have my injectors cleaned up now, but still have to check flows and spray patterns.

One site suggested painting the injectors. These old ones don't look fine, so not sure I will bother. Might do the holders though if they don't clean up too well.

[JeffreyNMemphis]

We are on a slippery slope when it comes to cleaning under the hood. If you get started, no telling when it will end... I was under the hood again today for 5 hours. Originally it was to check the water hoses between the engine and the radiator. Instead, I removed a hose that comes from the cold start valve to some other greasy Bosch part (about 3 inches) and cleaned the grease off the hose, the clamps, the cold start valve and the Bosch part. I also cleaned and polished the air cleaner (planning to steel wool and paint). I did get a peek at the water hoses, I am going to change them next week.

I wish I could pull the motor out and take the whole thing apart and clean every single nut and bolt. The leaking valve covers put a lot of oil on the motor and then the dirt piled up.

My preference is to have a very clean motor, so if something breaks or is leaking it is not hard to detect. Some people think it is ok for an engine to leak oil, I am not one of them. If something is leaking it has to be fixed or it nags at me. I have a lot more cleaning to do.

The car is running fantastic. I am making a to-do list. I refinished the top dashboard wood last week. Next I am going to refinish the window trim wood (it is dry and starting to feel rough).

Good luck with your install. It sounds like you are prepared.

Jeffrey