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  #1  
Old 11-24-2007, 11:56 PM
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Location: Coarsegold Ca
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Rebuilding Fuel Sending Unit

I pulled the sending unit in the wagon to clean it up - it wasn't operating properly. Once opened I noticed the wires were disconnected from the solder points and seemed to short to reattach. Looked around for either a new or used replacement and only came up with one north of $200.00. Hard to swallow when I know that once stock is replenished it would be about $80.00. I didn't want to wait until that would take place.

I thought about using thin wire but figured there was a resistance value that would not be the same and that would mess up the reading.

Off to the pick-n-pull knowing my chances were 1% that a wagon would be there...my thoughts being I would find one from a sedan and then use the guts to rebuild mine. The wagon is about 1/2 the length of the sedan (guess).

Found one in good shape (except for the gunk that went splat once opened).

1/2 off today so it cost me $8.00. Now onto cutting and soldering the wires.
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it

Last edited by BIGRED; 11-25-2007 at 01:53 AM.
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Old 11-25-2007, 02:41 AM
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Question

How did you open it up? My gauge would jump around from time to time when the tank is under a 1/4 full. I took the sending unit out, cleaned the holes and let the gunk drain out. Spilled half of it on myself! I couldnít figure out how to open it to check if thereís a loose wire. I put it back in the tank and the same thing happened.
Also, when fuel is low, there seems to be something dragging on the bottom of the tank when stopping and going. When I filled it to about half a tank, the sound went away. Itís very annoying.
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Old 11-25-2007, 02:51 AM
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Quote:
Originally Posted by SlashJoe View Post
How did you open it up? My gauge would jump around from time to time when the tank is under a 1/4 full. I took the sending unit out, cleaned the holes and let the gunk drain out. Spilled half of it on myself! I couldnít figure out how to open it to check if thereís a loose wire. I put it back in the tank and the same thing happened.
Also, when fuel is low, there seems to be something dragging on the bottom of the tank when stopping and going. When I filled it to about half a tank, the sound went away. Itís very annoying.
i am not 100% on this but your sending unit s different than his. yours you take out and it is a tube. at the bottom of the tube there is a spanner nut. it looks like a flat head screw driver with the center ground out so the bolt will go where the bit is ground out (like a two pronged fork, with wide prongs). if you take that nut off you can then CAREFULLY slide the tube off and clean up the inside.
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Old 11-25-2007, 10:09 AM
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Being that I have pulled both the SD's and now the TD's, they are the same in design concept. The difference is the length of the tube.

There is a tutorial somewhere on this site with pictures...having said that... there is a small plastic nut that you unscrew. That releases a round metal disc which lifts off, to be followed by a "labyrinth" looking plastic disc pressed in and flush with the tube. I wiggled that until it freely pulled straight out after which the tube will slide off exposing the guts.

You need to be careful as the wires can break loose.
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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  #5  
Old 11-25-2007, 08:42 PM
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Quite a frustrating day....

I took my time and swapped the wires.. reinstalled it and it read full tank (it ahs about 1/2). So I pulled it and out it comes in the basic same destroyed condition...a bit worse than one before it.

LIGHT BULB
I look under the fuel tank and notice it is dented in an inch or so...just enough to force the compression of the sending unit and blow it apart. Mind you that it doesn't hit when placing it in the tank prior to tightening it. The roughly 3/8" lower it goes with tightening was enough to break it up worse than it was. Fooled with it a bit more.. not a good idea in the state of mind I was in.

Can't rebuild it a 2nd time.. gonna track a new one down.
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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