Severe wobble in rear on bumps

I have a '99 Windstar SEL that has appeared to need rear shocks. I replaced them this weekend but now the shaking and wobbling is even worse after hitting even moderate bumps. Bumps that run across the entire lane width don't seem to cause the violent roll anywhere near as much as the random bumps do. I don't hear any unusual noises on bumps, just the shaking noises from inside the van. I felt as if I was going to lose complete control and drove home from the store very slowly to avoid accidents. Has anyone ever encountered something like this?

Phil

In the light of the morning I looked under and saw the broken axle bar. I'm amazed I was even able to get home at all last night. These Michigan roads really took a toll on that axle, it appears. I'm checking to see if insurance may cover that.

Phil

Sorry you have had this problem. Is it broken near the LH end? That seems to be where most have broken before. I have a theory that the breakage is actually caused by erosion/corrosion from drippage down onto the axle. (Crazy old man!!)

You are lucky not to have had an accident! Normally there are not a lot of mechanical forces in this axle member ... but without it, there is no rear wheel alignment. Very lucky!

Any chance you could post pictures of the damaged axle? I'm not in a cold climate and my vehicle has never seen road salt, but I'm aliitle concerned and would like to know what to look for before it's too late!

Sorry you have had this problem. Is it broken near the LH end? That seems to be where most have broken before. I have a theory that the breakage is actually caused by erosion/corrosion from drippage down onto the axle. (Crazy old man!!)

You are lucky not to have had an accident! Normally there are not a lot of mechanical forces in this axle member ... but without it, there is no rear wheel alignment. Very lucky!


Yep! Just like all the others, it broke about 18 inches or so from the left. Much closer to the left, the beam widens so it would be stronger at that point anyway. Where these are breaking is the point where the amount of metal is smaller and at the same time close enough to the "fulcrum" point, which is at the shock mount and spring. I just put new shocks on, but before that it felt "swervy" on bumps and we just figured that the new shocks would fix it. In fact, the new shocks may even have helped finish off the break since the new shock's resistance to rapid movement, such as a bump or pothole, would act as a fulcrum point and reflect the stress from the wheel to the inside part of the beam, putting a good deal of stress momentarily on that point.
Although rust may be a factor here, I really believe that it is caused by many years of flexing force from the bad roads and in the end is simple metal fatigue. Still, if the Ford engineers or the engineers involved with the design of that beam had thought more about that stress point and just used more, thicker metal at that point, these beams may never have broken. The ACTUAL cost of the additional metal surely would have only made a few dollars in cost of the part, and a drop in the bucket toward the cost of manufacturing the entire vehicle.
After some other sites that I read regarding this issue, apparently there are numerous complaints of this and it really is dangerous, beyond just simply a "wear-and-tear" issue. A major suspension component like this should be designed never to break. It just simply would not cost much to have made this beam virtually unbreakable at any age and mileage.

Phil

Living in the Southeast, my car has never been exposed to much roadsalt ... and the axle never showed any corrosion. But we recently had a little snow, and I drove across some salted overpasses and bridges ... so I took another look. Guess what! No corrosion for sure ... but a definite pattern of drippage and drying has occurred on the axle, leaving markings that definitely look like precursors to the problem. I'm gonna try to get a camera under there before the next rain washes the evidence away.