How do you fix a fuel sender to fuel gauge on a 72 beetle?

Answer 1

I also have a '72 beetle - with a busted fuel sender unit. I have the installed one and another older one. They both have a floater attached to an arm that makes contact with resistance wire on the inside of the unit. The resistance wire is wrapped on the inside. So the resistance (and thus the voltage reading) changes as the contact (floater) moves. It seems that the delicate resistance wire is the weak point in the design and usually breaks. The contact part that brushes over the wire also sometimes can be a bit bent. If you can see the wire is broken you can try to replace the whole winding by removing the old and determining the value (in ohms/meter) and buying new resistance wire and rewinding it. Alternatively try and replace the whole resistance wire setup with a potentiometer (variable resistor) - I think that probably better.

I actually got the old unit I had working this evening just to blow it up when I was clever enough to 'test' it with 12V without adding a current limiting resistor. before blowing it up I measured the resistance range: 0-400 ohms. the windings are regularly spaced, so the resistance should rise linearly with movement of the floater.

I see if i can get anything fixed and let you know. Otherwise, if you live in USA try wolfsburgwest.com in Cali. they have new ones for $33. I live in South Africa :( - so I'll probably have to try and fix it or pay like more than double that.....