My old style hand primer pump on the '79 300SD was weeping and when I removed it I found a spring and orange plastic part in the hole where it screws into.

It almost looks like a check valve but could it have been part of the old hand pump that separated? I left it in but should I have removed it when installing the new style spring-loaded pump?

I've replaced these before and don't remember seeing a spring down in the hole...is it supposed to stay or go?

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

http://www.peachparts.com/Wikka/PrimerPump

Here is a wiki on the job. It should look like this when installing the new pump.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

That's what I am used to seeing, but in this one there were extra pieces down in the hole of the IP housing which did not look like they came out of the old pump. A spring and a little plastic plunger piece. I left them in there but probably didn't need to.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Does it work alright the way it is? If so leave it, if not take the parts out. Hey if its not causing a problem don't worry about it.

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1983 300SD
200000miles

It seems to pump OK but the system is closed now so I cannot tell for sure. The EPC shows these parts as being a "repair kit" which consisted of a spring and plastic plunger piece...OK, I will just leave them in for now. Maybe they were some sort of check valve for it.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

When you pump the primer pump enough you should be able to hear fuel coming back through the return and if you do I'd just leave it. As you say maybe it's some kind of check valve that they thought might fix a leaking primer pump or something, it would be interesting to find out.

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1983 300SD
200000miles

Based upon my experience with these new pumps I would say it is pumping...there is definitely resistance once it got primed and you can hear the characteristic squeeel of the fuel in the lines.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz