Fuel Gauge Sending Unit Repair (Is It Possible??)

[Fred M.]

Hi,

After over 2 years of not knowing how much fuel is the tank of my '64 I finally removed the sending unit to investigate (had gauge checked months ago, all OK). Bent the tabs back and removed the cover on the small resistor-looking componet and found the culprit. A small section of the flat, wiring surface that connects with a contact point (driven by tank float) that moves up and down the surface was missing. It's the small contact point riding up and down the flat wiring surface that makes the gauge needle move. The missing segment of the flat wiring surface created an open circuit thus causing the gauge to malfunction. Anyone have experience or knowledge of repairing or replacing just the resistor section. Spending $145-$180 on a new sending unit is my last resort. TIA.

Fred

[James F.]

Re: Fuel Gauge Sending Unit Repair (Is It Possible

Fred, There are several advertisers in Hemmings Motor News that will repair these units. I believe prices are around $50-$60. Hope this helps.

[Joe Fisher]

Re: Fuel Gauge Sending Unit Repair (Is It Possible

Jim:

I just did my sending unit on my 61 that I just got. The sender was filled with muck and unusable. I was able to find a unit out of a 61 Chevy and used just the resistor element from it. Just a little solder and time, but saved a lot of money. Just be sure that the resistance value is the same as what your car calls for. any questions just email me.

Joe

[Brandon K.]

Re: new sending unit

I just got a brand new repro unit from a company in CA for about 80 bucks. havent installed it yet, but it looks identical to the original. email me if you want the contact info.

BK

[Jack H.]

Is It Possible?? Yes....

The price you quote for fresh replacement gauge is CHEAP -- most have kited into the $200 range with recent price hikes.

Inside gauge potentiometer unit you'll find (as you did), a wire wound resistor and a pot center wiper. Resistance should vary from 90-100 ohm value to a min of around 2-4 ohms when pot's wiper arm sweeps the wire wound windings.

If pot's wiper is bad/missing, you can replace with working unit off a scrap yard car of the era. I would NOT try to kludge a wiper contact using solder/iron-gun as you don't want it fall off once you've put the time/labor into the R&R (remove and replace) effort.

If the pot's resistance winding integrity is breached (broken), you can effect a repair that's 'virtually' undetectable. By cutting a small strand of bus wire (22-26 gauge), lay it across the section of the wire wound pot where the break is (out near the edge -- away from the path the pot wiper would sweep) and carefully solder it in to bridge the gap. Be CAREFULL not to 'blotch' too much solder and bridge more pot windings than necessary (guage could give 'jump' effect when pot wiper sweeps through this section as a result....

Last, if you're forced to get 'spare' parts from passenger car/truck of the era from a scrap yard. Consider moving the whole/functional pot assembly over on-to your existing gauge, but check for proper operation of the substitute part as well as compatibility of the resistance sweep range of the two assemblies. Then, while you're in there, get everything clean/fresh before you button up.

On mid-year cars, fuel gauge system differred from early (straight axle) or later (Shark) systems. Instead of guage being a simple variable resistance to ground setup, they built a whetstone bridge arrangement (keep absolute battery voltage from affecting tank readings). On these systems, you have to MAKE SURE you obey and maintain feed voltage and grounding (insulation on wires going to tank gauge pot) construction. Failure to do so, will result in an IMMEDIATE current overload inside the pot's wire winds and an open circuit. PLUS, if this happens with ANY electrical arcing while the gauge is sitting in a gas tank that's essentially empty but still contains residual fumes, you're a SOLID CADIDATE FOR KABOOM!!!!!