Thanks for the answers, but i guess it'll be cheaper to just buy a new temp gauge. I refaced the gauges, and noticed that the needle on oil gauge was pressed all the way to the plate, so hopefully thats the only reason why it didn't work.

The temp gauge tube is broken, so now i know why that one doesn't work.

Now i need to rewire the fuel gauge-fuelsender , but i thought it was supposed to be wires like this:
12V source - 6V resistor - Fuel Gauge IN
Fuel Gauge OUT - Fuel Sender Unit.

And then the fuel sender unit would be grounded. But now i saw that there are to connectors on the unit. I guess one (outer) is for ground and the other (center) is for to connect to the gauge?

picture of sender

the wires that are connected don't go anywhere.

Chevrolet 3100
Year: 1951
engine: inline 6 217CI
Transmission: Manual 3-Speed.
12Volt.