Author Topic: Fuel Sending Unit  (Read 3446 times)

Rolf

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Fuel Sending Unit
« on: March 29, 2007, 18:21:49 »
I know there are various threads on this subject but, I couldn’t find any that dealt with this problem.
I have a 1966 230 with a cylindrical type sending unit. It wasn’t working at all. A friend of mine lent me the older exterior float type and it didn’t work correctly but, at least, it worked well enough to show me the gauge was OK.  I remove my unit and took it apart. I found the wire for the gauge was broken. I searched for past posts on this and found an excellent one on testing the unit. The problem being, the wire is too short to re-solder, about 2 inches 2 short. I am assuming the wire is aluminum. I have tried to find a place which has it to no luck. I did find some wire, copper, just a tad larger and tried it to no avail. I do get the red light when I move the float to the bottom but, the gauge reads full no matter what position the float is in. Is there somewhere I can get the wire required, or do I have to get another unit? I did talk to Ray at Bud’s Benz and was told the cylindrical sending unit is the correct one for my car. He told me the older units were used up to the chassis number starting with 008 and mine starts with 012.  Thank You



Rolf
1966 230SL Auto
1992 300D
1991 FLHS
« Last Edit: March 29, 2007, 21:30:04 by Rolf »

hands_aus

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  • Australia, Queensland, Brisbane
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Re: Fuel Sending Unit
« Reply #1 on: March 30, 2007, 05:25:44 »
The wire is not normal copper wire but resistance wire.
Maybe an instrument maker repairer could help you out.

Alternately maybe an electronics hobby type store.

My understanding is that there are different gauges to match the different type of sender.

I have a problem with my sender and gauge combination but I have learnt to live with it. When my red light comes on I have about 35 litres in the tank.
Initially I thought the car was guzzling the fuel (and it was) but in real terms it turned out to be the miss match.


Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL #114, auto, ps , 717,717
best of the best

al_lieffring

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Re: Fuel Sending Unit
« Reply #2 on: March 30, 2007, 07:45:50 »
When I took my tank out for cleaning I found the float assembly tube full of sludge and it caused the wires to break when I disassembled it.
Trying to fix it I took several wire wound rheostats apart and tried to find one with the same resistance per inch as the wire in the float sensor. The closest I came was one that when installed went to full then only dropped to indicate 1/2 full when the reserve light came on. I gave up at that point and ordered a new one $155 usd.

Al

66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket

Rolf

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Re: Fuel Sending Unit
« Reply #3 on: April 01, 2007, 07:09:53 »
Thank you Bob and Al. I called all over my area to no avail. I can not locate a place which can help me with the wire. I will probably get another unit from Bud's Benz.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

Rolf

  • Guest
Re: Fuel Sending Unit
« Reply #4 on: April 13, 2007, 21:56:25 »
Thank you Bob and Al. I ended uo getting a new sending unit from Ray. The gauge is working fine. I am still looking for the proper wire in hopes of repairing the old unit.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS