The adjustment is easier, and somewhat more likely to be done accurately if the weight of the vehicle is supported by a jack before trying to tighten the adjusting bolt. Raise the truck by the frame, letting the front wheels hang free, and tighten the adjusting bolt a couple of turns with minimum load on it, then lower the vehicle and bounce it up and down a few times to let it assume its new ride height.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!