I believe I have a faulty fuel fuel pump on my 1968 280S (W108). The car sputters then dies. I see no fuel being sprayed into my carburetors. The fuel filter was changed approx 5K miles ago. No fuel comes out of the fuel line before the fuel filter. I see no rust or debris in my fuel tank looking though two fuel tank openings (the opening under the fuel tank cap and the fuel gauge opening in the trunk).

My best guess is a faulty fuel pump. Any thoughts?

My current fuel pump is a mechanical Pierburg. I have seen some posts about trouble finding the exact fuel pump replacement (some needing to retrofit aftermarket fuel pumps to work). However, I found this pierburg mechanical fuel pump that looks to be a match:

Amazon.com: Pierburg Mechanical Fuel Pump: Automotive

Before I pulled the trigger on this part, I was hoping to get the input from this board.

Thanks,
CNM

Does yours have the removable cap? If so, take the pump out of the engine, and open it. There may be quite a bit of dirt in the pump screen. You can also operate the pump by hand to see if it pumps, or if the diaphragm is torn.

Check this for a source: New Mercedes-Benz Fuel Pump OE# 115-090-01-50 (Fits: 280) on Ebay. There are also additional listings there; enter "Mercedes 280 fuel pump"

That pump does not look like any Pierburg I've ever seen. It looks like the crappy Vaico pump I bought for my m180 that constantly leaked oil out of the weep hole. It may be re-branded if it truly is a Pierburg.

It cost around $35.

__________________
1981 300TD 310k miles
1970 280sel 172k miles
1966 230 Fintail 162k miles

"Where are we going? And why am I in this hand basket?"

Not sure if mine has a removable cap or not. I haven't been able to find the right tool to unscrew the Allen bolts. Tight fit down there.


Hmmm... I have seen some of those cheaper fuel pumps around and have been trying to avoid them. However, the alternative is roughly $220 from a MB dealer.

Ug. You need a 6 mm allen wrench, the old style shaped like an L. The short end will barely clear. A 6mm allen socket won't fit.

FWIW I've been going through the exact same thing on my 1960 and 1963 Fintails which have the same pump and the same replacement pump. There are not rebuild kits available for the early pump. My replacement pump looks like the link you have but I paid $45 from an on-line outlet. I actually bought 2. One works fine, one leaks oil at the crimp seam and is going back.

In my mind there are two downsides to the replacement pump:

1) you don't get the primer lever which is VERY useful when you leave the car sitting for a week or three

2) you have to cut the metal fitting off of the fuel to carb line as it is expecting a compression fitting instead of just a hose and hose clamp.

Thanks Scooter. My 6mm allen wrench seems a bit to big to get in there. I have a slim pass through ratchet that should work and fits into the space. However, I havent found a 6mm head to fit it yet. Perhaps I need to search for a bit slimmer 6mm allen wrench instead.

It sounds like one of the cheaper fuel pumps may work. I am also waiting to hear back from my local MB dealer regarding their options.

My 6mm allen socket is longer than my wrench. I'm trying to remember, I think I had to take the fuel pump apart to get it off the 1960 and didn't for the 1963. But getting the new pump on was literally just barely possible.

After sawing off the tips of my allen wrench, I was able to get the old pump off. The gap between the bracket of the new pump and the actual head of the pump is slightly shorter than the old pump. As such, without shaving some metal off of the pump or the power steering, it just barely wont fit back on. In other words, I can get the bolts screwed back in, but the pump wont snugly fit against the engine.



FWIW, the new "pierburg" pump I bought from pelican parts appears a bit cheaper with the plastic end.

When I saw the "Piersburg" pump on-line I was concerned about the plastic end. WTF? Plastic? FWIW, I phoned Piersburg, which long ago sold off their mechanical fuel pump division, to another company. So the new "Piersburg" pump has nothing to do with the old Piersburg company.

I phoned Piersburg because doing a google search returned two different pumps for the same applications. One has the plastic head and the other doesn't have screws. I wanted to know which was correct or if both were correct. Needless to say, they didn't have an answer and the phone number that they gave me to call at some other company never returned my call.

In your situation I would return the pump and get the Meyle or MTC pump and hope it doesn't leak. On my car I could use that since there is nothing else in the way. Are you saying that the part of the pump that hits your power steering pump is the base flange or the screwed-together flange?

The Meyle replacement pump looks like your old pump. The MTC pump with a vendor sent me that I can't type here or it will flag a moderator that they sent me to replace the defective Meyle pump looks the same also except the hid is 90 degrees clockwise, which means that the fuel lines are not going to line up right.

The pump I was replacing was on an earlier car and it was mechanical with a manual pump lever. I wish I could get that rebuilt...

UG. I should have read this more carefully. I have a 1960 220S and a 1963 220S. I've replaced both (Meyle and MTC) and I'm on my 3rd new pump and they all leak oil out of the weep hole. What the hell!!!! I started a thread here, which is redundant with this one probably...

http://www.peachparts.com/shopforum/vintage-mercedes/362053-oil-drips-new-w111-fuel-pump.html

Did you ever come up with a solution to the oil leak on the pump???

thanks
Scott