Badger AB needle problem

Thanks, ok that narrows things down a lot. There is an F on the spray regulator. I'll check these out.

Your have the only three parts that are needed.  Something is wrong.  Here are some possibilities:

They sent you a wrong part or a bad part.  It happens sometimes.

The tip is not sealing against the body.  Try a little bees wax or Chapstick.  Check for burrs or scratches.

The tip has a split in the end.  Examine it closely with a magnifier.

The head isn't tightened enough.  Not very likely.  Just snugged up should be enough.

Which kit did you get, the fine or super fine?  If there is an F on the spray regulator it is fine.

Don

This sounds like a bad fit between the tip and body of the brush. I am not really familiar with that Badger model, but several of the Badger models have a teflon washer on the tip sealing the nozzle pieces from the body of the brush.  Blowback into the bottle is a symptom of that washer going bad.  Is there any chance you damaged that washer when working with the brush (if it has such a washer)?