Fuel Sending Unit Removal - PeachParts Mercedes-Benz Forum

S.Scogin · #1 03-13-2008, 12:32 PM

I was wondering if someone could tell me where the fuel sending unit is on the W123 chasis. Do I get to it from inside the car, after removing the first aid kit housing?

Thanks,

-S.

Jordan G · #2 03-13-2008, 12:41 PM

Right on, buckaroo. Big metric hex head though....46mm or 1 13/16" (cheaper to buy).

Having problems? Before you replace it....carefully clean with brake cleaner or something similar....lots of crud builds up in there.

Jordan G · #3 03-13-2008, 12:42 PM

Oh...and it's helpful to put your car/year in your signature too....you indicated w123 - which helps....but it's easier

Welcome to the forum

Chad300tdt · #4 03-13-2008, 12:45 PM

Welcome, and I agree, your comment about the first aid kit tipped us off that you had a sedan, but wagons have a different location for the FSU.

Info in your sig is a huge help.

Dee8go · #5 03-13-2008, 12:46 PM

So, where would it be our our cars, Chad, next to the tool kit?

Chad300tdt · #6 03-13-2008, 12:57 PM

Quote:

Originally Posted by Dee8go

So, where would it be our our cars, Chad, next to the tool kit?

Under the hatch floor. I used two channel locks to remove it. It's not too tight since it's compressing an o-ring as a seal.

mobetta · #7 03-13-2008, 03:34 PM

I use a standard vise grips all the way open, and a large screwdriver to provide leverage.

If you have a third row, you can access it by only removing the forward part of the seat, and peeling the cover to the back of the car.

dont know about 2 row cars

S.Scogin · #8 03-13-2008, 05:32 PM

Thanks everyone. I think I found my new favorite place for information for my Benz. Oh, and sorry about the lack of signature, I thought I already set it.

pawoSD · #9 03-13-2008, 05:38 PM

Quote:

Originally Posted by Chad300tdt

Under the hatch floor. I used two channel locks to remove it. It's not too tight since it's compressing an o-ring as a seal.

Wow...wagons have a secret compartment!

300SDog · #10 03-13-2008, 05:54 PM

And best done with tank nearly empty on the 123. You'll need a small bucket to catch diesel fuel otherwise spilled all over the seat. Careful of breaking piano wires if ye disassemble it too.

Chad300tdt · #11 03-13-2008, 06:07 PM

Quote:

Originally Posted by 300SDog

And best done with tank nearly empty on the 123. You'll need a small bucket to catch diesel fuel otherwise spilled all over the seat. Careful of breaking piano wires if ye disassemble it too.

Here's a photo of the "piano wires". My ground wire was broken so I cut a tab from sheet copper and soldered it back. Everything works great now. Unless the center rod is completely corroded and the jewel float or base is broken, you can fix the one you have.

S.Scogin · #12 03-19-2008, 04:13 PM

Quote:

Originally Posted by Chad300tdt

Here's a photo of the "piano wires". My ground wire was broken so I cut a tab from sheet copper and soldered it back. Everything works great now. Unless the center rod is completely corroded and the jewel float or base is broken, you can fix the one you have.

How did you take the cover off the sending unit? I tried doing that the other day but didn't see how it came off.

Dee8go · #13 03-19-2008, 04:16 PM

I learn something new here everyday! Some of it is actually useful stuff.

Thanks, Chad.

Chad300tdt · #14 03-19-2008, 04:20 PM

Quote:

Originally Posted by S.Scogin

How did you take the cover off the sending unit? I tried doing that the other day but didn't see how it came off.

At the bottom of the unit is a nut that I used a snap-ring pliers to remove. You could find a screwdriver that fits the width and grind out the center too. Watch how the parts come off so you can put them back the same way.

Stevo · #15 03-19-2008, 04:23 PM

Quote:

Originally Posted by S.Scogin

How did you take the cover off the sending unit? I tried doing that the other day but didn't see how it came off.

Theres a tiny nut in the center (bottom) surrounded by, what looks like a little piece of plastic hose, you must get rid of that too get to the nut. And be careful, tiny wires when you get inside.