Fuel Level Switch

I bought a new fuel level switch on ebay, but it`s leaking... 99% sure the fuel is coming from the whole where the cable goes through, see attached photo.
I can move it some back and forth... I assume these is something these is common ? what is the best way of handling it?
I will let the switch stay in oil for the night, maybe the rubber will increase and it will stop leaking?

Temporary have I used another socked I had and glued the whole again... so I can use the bike until I get the one with the switch working without any leaks.



Temperary fix until I got the other working correct without any leaks:

Mine leaked but soaking in gasoline for an hour or so swelled up the rubber seal and it hasn't leaked since. I made sure to keep the wires that sit outside the tank out of the gas. Only the part that gets exposure inside the tank was soaked.

Nessism wrote: Mine leaked but soaking in gasoline for an hour or so swelled up the rubber seal and it hasn't leaked since. I made sure to keep the wires that sit outside the tank out of the gas. Only the part that gets exposure inside the tank was soaked.

Will go out and change from oil to gas thank you !

Nessism you was spot one here... 4-5 hours in the gas removed the leak

Now I need to function test the level switch by using some gas

Mine was leaking there at the red plastic, so I sealed it with Permatex liquid metal. It comes in a tube. It is a 1-part epoxy.
I put the stuff on the outside of the fuel switch, and I didn't gob it on. I only used enough to cover the red part. After drying, it feels like plastic.
That repair was done several years ago, and it is still good. no leak. Seal-All is another product and there are probably others that will work.