Over the years I have removed the gas tank sending unit from my 230SL, cleaned it and put back into the tank. It did finally give out though so I found what was billed as a "replacement" on line. Bought it for around $165 and yes it did fit but the connector on the top did not match mine so I sent it back. Subsequently bought a VDO sending unit for $27, which looked very much like the $165 unit. The connector is not the same as mine but with a small mod it all fits and works well. The mounting holes are in the identical same place as the original sending unit. For $27...I'm happy with it!
Should you elect to eventually go this route, you need to know the ohms range of your existing unit so that you get correct readings on your gauge.