I had a ball joint to fail as I was getting off the interstate. One scary ride. Luckily my truck didn't suffer any damage. If it would have failed just moments sooner it could have been catastrophic as I was running 70 mph. I had some symptoms prior to failure including stiffness in steering and a pronounced squeak from front end. After getting truck home and replacing all the ball joints,I discovered that the broken one had no grease in it. Another thing I found is that sometimes if u run grease fitting all the way in no to very little grease goes in. Hope this helps.