How to repair a MB/GPW fuel gauge. Lots of pics

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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YLG80
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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by YLG80 » Fri Nov 25, 2011 5:20 am

For a complete information on fuel gauge repair, here is a picture of an Early Fuel gauge in restoration.
The general principle is the same, but the 2 coils positions are different.
The picture shows the gauge in a mid position (1/2 full)
early_fuel_gauge-web.JPG
early_fuel_gauge-web.JPG (40.77 KiB) Viewed 6806 times
Yves
Ford GPW 164794 1/4T 12-7-43 - Frame# GPW*239762*
ACM I body#198443
Restored as 1st Army 759th LT B21
ON6YD(ex YB1AUH)

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by mandrake » Sun Sep 09, 2012 2:24 pm

Hello,
the value between the two connectors is 38 so i think it's ok but the value between the left connector and the brass li is 51...isn't it too much?
Pleas let me know i it's ok or not

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by Akiss » Sun Nov 18, 2012 6:38 am

Great post thanx :)

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by Chuckman84 » Tue May 28, 2013 5:32 pm

ok, so I tried this, and broke my glass while doing so. anyone know of a vendor who could sell me the glass and the rubber(ish) gasket? Id love to keep this thing vintage and original as can be.

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by JLR » Wed May 29, 2013 1:25 am

Good morning all,
This is a subject about which several of us (non-electricians) are scratching our heads at this very moment, so your help would be greatly appreciated.
Here in France, we have 6v, 12v and 24v jeeps.
The spare parts Dealers have 6v and 12v dashboard gauges (not 24v), and only one sort of gas-tank transmitter which is supposed to work with all 3 voltages.
The Dealers tell us that gauge and transmitter must be matched.
What is your verdict on the following questions please :-
1- can a gauge marked 6v work properly with a 12v or 24v circuit ?
2- can a gauge marked 12v work properly with a 6 or 24v circuit ?
3- can the tank transmitter work properly with any of 6,12 or 24v circuits ?
4- must the gauge and transmitter be matched ? If so, how is this done ?

Many thanks for your help in solving these "froggy questions" !
John

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by MB1943EB » Tue Nov 26, 2013 1:48 pm

JLR wrote:Good morning all,
This is a subject about which several of us (non-electricians) are scratching our heads at this very moment, so your help would be greatly appreciated.
Here in France, we have 6v, 12v and 24v jeeps.
The spare parts Dealers have 6v and 12v dashboard gauges (not 24v), and only one sort of gas-tank transmitter which is supposed to work with all 3 voltages.
The Dealers tell us that gauge and transmitter must be matched.
What is your verdict on the following questions please :-
1- can a gauge marked 6v work properly with a 12v or 24v circuit ?
2- can a gauge marked 12v work properly with a 6 or 24v circuit ?
3- can the tank transmitter work properly with any of 6,12 or 24v circuits ?
4- must the gauge and transmitter be matched ? If so, how is this done ?

Many thanks for your help in solving these "froggy questions" !
John
Gidday,

anybody here who could give answers to JLR's interesting questions? I'm most interested in question no. 4.
Would be glad to get some information. Thanks.
Eckhard
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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by parcours » Tue Jul 21, 2015 5:26 am

EXCELLENT Post.

Bringing it back to life...

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by Seff » Thu Nov 05, 2015 2:43 am

The tank sender unit is a variable resistance. This resistance, if it goes from 0 to x Ohm, should work equally well on 12 V and 6 V. They don't, though. There's always some resistance in them, and they can never cut/"resist" 100% of the voltage.

The gauge should be voltage-specific.

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by rich42gpw » Tue Jul 02, 2019 4:26 pm

Thanks for all that!
My insulator washers came apart on disassemble
Any way to get more.

Also they go on the inside of the gauge correct?
RICH

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by trifido » Fri Aug 16, 2019 2:28 pm

Hi,I have repaired this FG and after multy-meter testing theese ere the results
Attachments
fg3.jpg
fg3.jpg (72.01 KiB) Viewed 3046 times
fg2.jpg
fg2.jpg (89.06 KiB) Viewed 3046 times
fg1.jpg
fg1.jpg (86.9 KiB) Viewed 3046 times
fg4.jpg
fg4.jpg (21.71 KiB) Viewed 3046 times

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by Finn42 » Sat Sep 14, 2019 5:03 pm

Does anyone know if you need the insulated clamp in the back? The rings that go around the posts on the clamp have disintegrated. Additionally, anyone know how to recreate the insulators?
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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by JAB » Sat Sep 14, 2019 6:50 pm

Yes, they are necessary to prevent the wires from grounding out or shorting instead of going to the "meter" part of the gauge (the coil).
-Jeff

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by 85jeepcj » Sat Sep 14, 2019 7:23 pm

I got very similar resistance readings on a NOS gauge.

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by Juno » Mon May 18, 2020 10:37 am

My test readings after repairing the gauge are very similar to Trifido,s but the needle still jumps to FULL when installed in the Jeep. Is this likely to be an earthing issue in the dash or is that 85.8 ohms reading on one post to body an issue? Any thoughts?
Cheers
Sean.

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Re: How to repair a MB/GPW fuel gauge. Lots of pics

Post by YLG80 » Tue Jul 14, 2020 2:07 am

Hi Sean,
I would opt for a grounding problem.
• If your gauge is permanently stuck on the full mark it most likely is not making electrical contact with the dash panel .
->A clean metal to metal contact between the gauge body and dash panel is needed to provide a current path for coil B to ground at X on the circuit .
fuel_gauge-schematic.png
• If the pointer is jumping upwards towards the full mark there may be some paint or rust causing a intermittent path to ground at X .
• Conversely if you have a dirty or intermittent ground connection at the sender unit your gauge will jump around or be permanently stuck on empty.

You first need to be sure that the gauge is grounded correctly internally. When I repair a gauge, I usually add a ground wire soldered between the gauge and the housing.
Then you need to be sure that your gauge is correctly grounded to the dash panel.
Check also if your sender is correctly grounded.
Yves
Ford GPW 164794 1/4T 12-7-43 - Frame# GPW*239762*
ACM I body#198443
Restored as 1st Army 759th LT B21
ON6YD(ex YB1AUH)

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