WD proper setup-bars-and level tow vehicle

You should not try to level the trailer with the spring bars. You level the trailer by moving the hitch head up or down on the draw bar or shank. The spring bars should be tightened just enough to return the lost weight from the front axle of the truck when you put the trailer tongue on the ball.

I suggest you take a long look at this thread, which is stuck at the top of the Towing forum, for help on setting up your hitch correctly.
Barney