[dsraven]

on that front end knock on turns, check to ensure the control arm bolts are tight, the ball joints are tight, the tie rods are tight and not bottoming against a frame that maybe shoudda had a C notch, the steering rack is tight and, if you have one, check the steering stop interference with the spindle. some have an adjustable bolt that stops the spindle from turning past a certain spot at full turn. it bottoms against a flat spot that is sometimes not flat so when the steering is turned to the stop point and the suspension is also going over a bump the stopper bolt is forced out of it's rabbit hole, or low spot, and can make that bumping noise. some front ends rely totally on the rack for maximum turning. anyway, better find out what the problem is sooner than later. don't wanna find out the hard way, loose control, and be looking at the grass from the bottom side.....
got a pic of the front end, maybe a couple of pics so we can see both sides and the rack? could it be a spring that doesn't fit into the spring seat well and is moving? usually a tell tale is a bit of rusty powder in the area, that denotes something is moving metal on metal.