Fuel Gauge Sending Unit

[volts101]

I have identified that my fuel sending unit is suspect on a 1967 BJ8.
It only gives 9 ohms with a full tank.
The gauge is OK and reads F with 70 ohms connected at the Sending unit.

Question is if the tank needs to be drained before changing the unit.... ??

Also is there any merit in opening the top cover (4 brass screws) to see if there is anything obvious to fix/fiddle with inside the unit ???

 

[Bobbydsport]

you don't have to empty the tank. I removed the 4 screws on my '67 BJ8 sending unit & removed it & then cleaned it with a q-tip & lacquer thinner. The only trouble was it still only registered 1/2 full when the tank was full. So I ordered a new one from a supplier & installed that one only to find the same reading at the gauge. Now I'm thinking the gauge needs to be re-calibrated.

Bobbyd

 

[vette]

you can move the magnets around on the back of the gauge to get it to read more accurately. I was able to get my gauge to read fairly accurately by just moving the magnets without the use of any external resistors or circuitry. I filled the tank and adjusted the magnets to just get the needle to go to full. Drove the car till I had a half tank verified by a wooden dip stick in the fill pipe. Then moved the magnets till the needle registered 1/2 tank. After about 2 more full tanks and some minor adjustments on the magnets the gauge was reading accurately.

 

[BigGreen]

... Question is if the tank needs to be drained before changing the unit.... ?? ...

No, but disconnect the battery to prevent sparks