Lube enough to get the job done no more/no less.
You can use running water (steady stream/not full blown jet), over the fittings/connections to help isolate the leak, or shaving cream, foaming/not gel.
Run water/or place shaving cream on fittings and such, keep an eye on the basket and watch for the air bubble to dissipate, go slowly.
With the shaving cream you can watch it get sucked into the leak.