My Porta Mount's altitude axis is loose, but it's not that it spins too easily, because I know how to tighten that down. I can pull the portion that rotates a small amount away from the arm and push it back in place, so there is a little slop now, and the weight of the scope pulls it slightly away from the arm, so the worm gear doesn't grip as well.
When I rotate it in altitude I can hear more noise in the axis than I remember, you can tell the worm gear isn't gripping the best because it barely turns with weight on it, despite being tightened down.
I tried tightening down everything else and it didn't make a difference.
Here's a shot of the gap i'm talking about.