Tech Question - Ziebart

I was hoping that you would be able to enlighten me some on the leaf spring failure that occurred on my 1991 Jeep Grand Wagoneer. The vehicle has around 140,000 miles on the odometer and has never seen a Buffalo winter or been abused.

A few weeks back I was on my way to a friend's house when coming to a stop I was greeted by a loud pop and a groaning/grinding sound that turned out to be my front springs. I managed to limp the car the entire way home and found that all but one of the driver's side leaves snapped just past the U-Bolt between the axle and rear spring eye.

Upon closer inspection of the driver's side spring I noticed that some of the broken leaves were already rusting where they had snapped indicating this damage had been happening for quite some time.

After removal of the passenger-side front spring I also saw that a leaf in that pack had snapped in the same location.

I read on your question of the week page that the leaf spring steel does not respond well to being greased and was wondering if the Ziebart protection I had done might have the same effect as greasing springs? - Charlie

Charlie, I do not think the Ziebart had an effect of the life of the springs. Springs breaking away from the u-bolt area shows that lose u-bolts were probably not the cause. As you were braking the springs under went wrap-up, that is they tried to pivot around the axle while hold back the force of the vehicles weight. Springs break on rebound, that is when the weight is removed and when the vehicle is coming to a stop the weight is off the back 1/2 of the spring. This is when yours broke. Many other factors, including 140,000 miles, could have lead to their failure. It is hard to take a guess as to what could have caused them to fail without seeing them. However, I would not be too concerned just because of the 140,000 miles they have seen, the springs lived a long useful life. -