Sink driving me NUTS!!

I bought a travel trailer that has copper tubing throughout the trailer. It's pretty old, but I thought I would be able to fix it up. I got tverything in the trailer working good EXCEPTthe bathroom sink. It keeps leaking from where the copper tubing connects to the sink. No matter how much I tighten the fitting it doesn't seat propperly. I've never really messed with copper before, and don't want to mess it up.

thanks in advance

If the lines are 3/8" with brass ferrules you need to cut out a section of it then replace it with new copper and a new ferrule.

The old one is most likely distorted to the point that it will no longer work.

sink

if you are trying to screw copper adapters onto the faucet, it will always leak because the faucet has straight threads intended for a nut and gasket seal.