I have a 86 F150 4x4 (33x12.5) 136,000 miles. Lately I have developed a vibration in the front end on the right side when braking. I also have been feeling a thump like something hitting the bottom of the cab when turning at slow speeds. This usually happens when backing out of parking spaces. I have been told that my radius arm bushings might need replacing.How can I determine if that is the true problem? And if it is the problem, how much should I expect to pay? If it is not the problem, what could be it possiblly be?

 

You can generally tell by looking...... they're the arms that lead from your front axle approximately 16 inches or so towards the back, and then attach through a bushing into a bracket riveted to the frame. You can jack up the truck and look at them, or observe them from the ground, from alongside the vehicle (NOT directly in front of or behind the tires) while a friend slowly moves the truck forward and backward by a couple of feet. You should be able to see any play, especially when the brakes are applied or released. As for labor, I don't know. I replaced my own, but it's involved. The "proper" way is to basically pull the front suspension forward, to position the radius arms forward enough to R & R the bushings. I cheated. Instead, I chiseled off and removed the rivets securing the aft bracket to the frame and left the suspension in place. After replacing the bushings (use polyurethane..... they're less expensive and higher quality than the stock rubber), I reattached the brackets to the frame by running Grade 8 bolts through the rivet holes. Should I ever need to replace them again, I'll simply need to unbolt the brackets.