Linking the fuel injectors on my 81 300SD are rubber lines. Because one was leaking, I replaced it with a vacuum hose. As I was doing that, I noticed that the injector closest to the firewall had a short bit of hose that was plugged. Is this supposed to be this way, or is the line from the last injector supposed to go somewhere?

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1981 Mercedes 300D - 300 000 km
1980 Camaro Z28

The #5 injector has the very last bit of hose plugged.

Your setup is perfectly normal.

Yes, these are return lines and the end one is plugged which is correct but you should NOT use vacuum hose on them. Get a meter of braided diesel return line and install that. The vacuum hose will not stand up to fuel and you will have more problems than you have solved.

That is special hose which is designed specifically for the purpose. It is not very expensive and you can get it from most good auto parts stores, the MB dealer or a VW dealer. Remember to ask for braided fuel return hose.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Thanks for the tip on the hose.

Fuel was dripping out at an alarmingly steady rate, so a quick fix was needed. I'll pick up some appropriate hose tomorrow.

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1981 Mercedes 300D - 300 000 km
1980 Camaro Z28

I agree...do not drive it with vacuum hose...it going to pop and dump a LOT of fuel while driving and cause a fire......

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Erikir,

The injector bodies are made the same so they are interchangable. Thus number 5 or the last one on the rear of the engine has an extra nipple. So this nipple has a plug on it.

Don't distrub the plug if it doesn't leak. But do replace all the other injector return line hoses with the correct hose or you can lose a lot of fuel.

Using hoses was a MB cost reduction. Older engines had metal lines that never needed replacement. But it doesn't save us any money when we have to replace the hoses.

P E H

Those metal lines were a PITA, as the injector had to be assembled on a jig to get the fitting in the correct place!

Rubber hose is MUCH easier!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Vac line is a NONO..it will turn to mush in no time flat (not to mention the heat involved).
That braided stuff is actually very similar to VW fuel line...only smaller. You will notice this when you go to remove it and it doesn't want to budge (good stuff)