Author Topic: Fuel sending unit repair  (Read 3549 times)

dirkbalter

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Fuel sending unit repair
« on: June 25, 2017, 20:41:31 »
Hello all,
I am attempting to repair my broken fuel sending unit. One of the lower taps of the u-type wire is broken and needs to be re-soldered. My question however is regarding the routing of the wire on top. I attached to picture. I routed the wire through the gaps or hooks in the plastic bracket. In doing so, the wire will touch the metal hex nut and stem. I don't believe that's right. Does anybody know or even better, have a picture of how the wire is run?

Thank you
Dirk

 
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

mbzse

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Re: Fuel sending unit repair
« Reply #1 on: June 25, 2017, 20:53:32 »
Quote from: dirkbalter
.../... does anybody know or even better, have a picture of how the wire is run
Try this. In the second picture, I have tried to enhance the wire routing in red
/Hans S

dirkbalter

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Re: Fuel sending unit repair
« Reply #2 on: June 25, 2017, 20:59:47 »
Hans,
Excellent.
Thank you.
Dirk
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

ja17

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Re: Fuel sending unit repair
« Reply #3 on: June 26, 2017, 14:33:36 »
Many W108 sedans of the era used the same sender, if you can find a good used one.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

dirkbalter

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Re: Fuel sending unit repair
« Reply #4 on: June 26, 2017, 16:29:03 »
Thanks for the tip.
I will give the soldering a try and see if it works. Is there a way to test the unit (meter it out between the poles)?
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

mbzse

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Re: Fuel sending unit repair
« Reply #5 on: July 02, 2017, 15:11:11 »
Measure resistance between "M" and "G". Should read some 70 +/-1,4 ohm when float is at bottom and 4,7+/-0,4 ohm when it is at the top. This is what affects the red needle in your instrument binnacle fuel gauge.
"W" is for the red "near empty" warning light.     Masse = Ground
« Last Edit: July 03, 2017, 10:40:03 by mbzse »
/Hans S

Anthony

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Re: Fuel sending unit repair
« Reply #6 on: July 03, 2017, 09:01:33 »
We're expecting a new shipment repro fuel sender units for the later W113 models any time now in case you're not able to fix the current unit.

dirkbalter

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Re: Fuel sending unit repair
« Reply #7 on: July 04, 2017, 23:05:57 »
Hans,
Thank you for the help. I soldered the contact but than slipped and snapped the wire in an attempt to route it before I even got to measuring.
Anthony thanks as well. I just received a new one from the mb classics center here in Irvine. (Fairly reasonable price I believe)
Dirk
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI