66 Fuel Sending Unit Issues?

[Mark P.]

I recently pulled my 66 fuel tank to repair a slight leak and after repairing it and re-assembling, found that the gauge reads 3/4 full with only 5 gallons in the tank. After messing with it, (lifting the arm up and down in the tank, it won't read below 3/4, but will read full when the arm is lifted to the top. What gives? I was very careful with the unit upon removal and disassembly. Contacts are clean and bright.

What did I do wrong or is it just a sign of old age? (the sending unit, not me...or it could be me, too.)

Any advice would be appreciated!

Mark