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Discussion Starter · #1 ·
Does anbody know the thickness of the wire used inside a GT gas guage sending unit? I've got one I'd like to fix, but there is no wire to measure off of.
 

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boomerang opeler
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dave if no one has posted an answer by tomorrow i will open my tank and check for you (i think you are on about the wires inside the tank ? yes
 

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Discussion Starter · #3 ·
There is a loop inside of the sending unit that the float rides on.
 

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boomerang opeler
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ok i will post in about 6 hours after i have some sleep :D
 

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Nichrome fuel gauge wire . . .

VERY thin strand of nichrome wire in one continuous loop from contact, down one side of post "T", across insulator "T" at bottom of post, then back up to mounting plate and grounded there. Two sets of brass fingers on each side of float "grab" wire and provide bridging contact for variable resistance as float rides up and down on center post. All of this is inside of tube. Most common problem I've seen is corrosion at the "ground" side connection, i.e. becomes ungrounded.

Check OGTS for nichrome wire, I think Gil has it.
 

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Old Opeler
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6v

"All GM cars use the same resistance in the sending unit for both 6 & 12 volts.
Never apply any current to the wire between the tank and the gauge or you burn out the sending unit. The gauge MUST be in the circuit as on 12 volt sustems it has an internal voltage regulator which steps the voltage down for the sending unit." Great thing the Search feature........

Sounds like the same sized wire is used in all GM fuel senders and I have a hazy recollection that Chevy sending units use 0.043" nichrome wire - but it has been a while since I fixed a '57 Chevy fuel sending unit .... best verify that size by actually measuring the wire inside an Opel unit. ;)
 

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boomerang opeler
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never looked at 1 of these before so dont know if this is normal but mine has this in and no wire i would want to go looking for sorry dave

ps theres an avatar for you if you want it
 

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Discussion Starter · #8 ·
Baz, if you remove that little nut on the bottom off the cylindrical section it comes off, exposing the wire and float.
 

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boomerang opeler
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just over 3 thou dave call it 32 /10000.inch :eek:
 

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I just repaired two units last week. The main problem encountered is as previously stated which is a bad ground. The only way to repair the bad ground is to carefully grind off the rivet, clean all the copper parts and the top of the sender unit, and then replace the rivet with a screw. As far as the wire goes, I noticed when browsing for VW part on midamericamotorworks.com that there is a VDO sending unit for 70's vintage VW's that looks almost exactly like the Opel unit. I would think that the internals would be the same since it's for a VDO gauge. If I could not fix mine I was going to buy one of those units and try to make a good Opel unit using the parts as necessary. Fortunately, I got mine working perfectly.
 

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Discussion Starter · #11 ·
Jeff that's not the only way. If you can generate a ground anywhere in the circular ring it has the same effect. Grinding is not needed as you have a good insulation barrier already. I have one in the truck that has problems now and will be looking into it as time permits as more tanks, senders and cars show up.
 

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I guess if you wanted to you could use a very short self tapping screw and solder a wire onto the copper spring and then attach it to the screw to supply ground to that side of the nichrome wire. The only problem there would be to make sure that the heat does not travel to the soldered joint of the nichrome wire and knock it loose. The tension on the nichrome wire is caused by the copper spring, so it would not take too much heat to soften the solder enough so that it would want to pull out. I am sort of a make it as close to original design as possible kinda guy, so I removed the rivet and restored the ground where it was supposed to be.
 

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Could this wire just give out, I filled my tank up for the first time on friday, the gauge read full, I shut the car down for the weekend and when I started it this morning the gauge reads empty.
 

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Discussion Starter · #14 · (Edited)
Yes the wire can just break. It could be a bad connection too, so I'd start there.

If it does turn out to be the wire keep it around. I found a spool of the correct wire for them. I haven't picked it up yet but 100s of feet for 15 bucks would do a few broken ones.
 

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Did you ever get the wire?

nobody said:
If it does turn out to be the wire keep it around. I found a spool of the correct wire for them. I haven't picked it up yet but 100s of feet for 15 bucks would do a few broken ones.
Say, did you ever get that wire? And would you be willing to part with a small amount (say, enough to fix my guage)?

Tried to PM you, but your mailbox is full.

Thanks,

jtb
 

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Discussion Starter · #17 ·
Sure no problem, I cleaned out the PM box a bit so just send me your address and I'll send you a couple yards of it.
 

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Discussion Starter · #19 ·
When I did one here they sold the wire by the pound and it is probably 1000 yards considering the size and the weight. The whole spool of it was something like 17 bucks. Believe me, I can't give it away fast enough to get rid of it all. The spool weighs around 8 pounds and is 5 inches by 4 inches and full. The cost of a stamp is worth it to start moving it out. That's why I offered yards not feet.
 

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OK guys, I took my spare sending unit apart with the idea of restringing it, cleaning connections, etc. I assume that one end of the wire attaches to the springy copper thing and the other end attaches to the rivet. (soon to be brass screw and nut). I'm confused about how the wire wraps around the plastic piece on the end of the post. It looks like if I just thread it through one notch, over the plastic piece and back through the other notch, it will contact the post which appears to be attached to the case, i.e. ground. Does anyone know how you go around the plastic piece without contacting the post? Maybe a picture.
 
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