I took my truck out of town the other day and at highway speed (75) hit a pretty pretty solid bump. At this time truck started shaking so hard I felt like it would rattle my teeth out. It didn't really want to jump from side to side as long as I held the wheel straight, but steering was very poor as one might imagine. The shaking continued until I was able to get the speed down to around 40-50 and then it smoothed back out. This process continued several more times for the duration of my trip.

Obviously this is not normal and I'm sure there is something worn out on the front end, I'm just not sure where to look first. Any suggestions would be appreciated.

The truck is a 95 F-150 2WD 300 six 5-spd short bed. It has 182k miles on it and to my knowledge the front end has never been touched aside from radius arm bushing a few years back. We used poly bushings for those and they seem to still be in good shape. Also, the passenger side front wheel is wearing really badly on the outside edge. I thought this might have been due to worn wheel bearings that I recently replaced when I did my brakes, but I think it has actually gotten worse since then.

I'm thinking tie rod ends and / or ball joints but wanted to get some other input.

Thanks in advance!

 

Yesterday I took the front wheels off and did some looking, shaking, poking, etc. The ball joints and the tie rod ends look ok, or at least don't appear to be obviously worn out. I suppose I could replace it all, but that's a costly proposal that might not fix the problem. I really don't like just throwing parts at it when my budget is already very tight.

Any other suggestions?

 

Sounds like you have bump steer, does your truck have a steering stabilizer, its the shock looking thing in the front end mounted on the steering arm between the two front wheels. When this goes bad it causes bump steer. A new one is usually about $30-$45 from the dealer. Hope this helps.

 

I don't believe the 95 has such a thing. It still uses the twin i-beam suspension.

To further clarify, when this starts happening, the vehicle does not want to dart to either side, it generally remains in the direction it was going. It literally feels like the front end is bouncing up and down violently. Think about maybe what a series of closely spaced speed bumps would feel like if you hit them at about 100 MPH. Furthermore, the problem continues well after the problem with the road surface is resolved. For example the road surface can be perfectly smooth but a bad transition off of a bridge will set it off. Once it starts, it continues to vibrate even if the road surface is as smooth as glass until the vehicle is slowed to around 45-50.

While the truck is "bouncing" steering and braking suck but they do respond. You don't have to correct it or counter steer, just hold the wheel straight and you'll keep going straight.

 

My guess is that you bent the i-beam or something in that area. You would need to be replaced it and have the truck an re-aligned. An alignment shop should be able to tell you if it is bent.

 

may need to have your tire re balanced, hitting a large bump at that speed may have thrown it off a bit. happened to me before i did my lift, hit a bump and popped the balancing weights off one tire. also check your front wheel bearings, and the caster/camber bolts. jack the truck up and if there is the slightest play in the ball joints or any other part, replace it. your problem sounds similar to whats know as the "death wobble" which is more common on lifted trucks. it could be caused by one thing or a number of things. it could even be simple as a bad shock. you never really know till you dive in! my $.02

 

Have you ever replaced the shocks. Shocks that are totally gone or broken will give you a problem like that.

 

It sounds like a bad tire or out of balance wheel. If you have a decent spare tire, I would try switching it to all four positions(if necessary) this would be a cheap way to eliminate that possibility.

 

I'd recheck the wheel bearings, tie rod ends, steering box, and while the wheel is off the ground, spin it to check for blisters on the tread. Also look at the bushings at the inboard ends of the axle beams.