my truck is a 98 f150, 4x4, 4.6. when i am braking and just when the truck is about to make a full stop, there is a clunk in the front end of the truck and kind of feels like a jerk, just slight. i dont know if that would have anything to do with the braking, but i got under the truck today, and the idler arm is original, and looks pretty bad, like 15 year old grease and oil caked on it, and i pushed the bushings with my finger and the bushing was soft and left an indention of my finger.

 

You need to grab the tie rods, idler arm, etc. and try to shake and move them and look for play in all the joints.