Hello all. For the past 6-7 months my truck's (2003 Ranger - STD / 2WD / 2.3L / Auto / 98.8 k mi.) "fishtailing" has progressed from the normal movements of a light truck of said configuration to an overall issue of driving instability. It is not uncommon when driving around corners at speeds as low as 25 mph to feel the rear end wanting slide out, even on dry pavement or asphalt. When driving over an extended portion of obscure surface (ie multiple railroad tracks) the vehicle reacts in a motion I can only describe as being similar to a fish swimming up a stream -- a swaying from side to side which seems to want to rotate the rear counter clockwise. It is a motion which feels (at least to me) very unnatual -- as if the truck were 2 seperate pieces held together by a swivel in the center. These problems are becoming worse, to the point where I am contemplating selling the vehicle.

After dealing with this issue nearly every mile of 2 seperate 2900 mile round trips to the west coast and back to the midwest in a span of 6 weeks, I recently replaced:
Brakes - total front and total rear including lines and fluid.
Upper Ball Joints & Control Arms
Lower Ball Joints
Front Wheel Bearings
Alignment
The truck has also had proper oil/fluids changes and aside from a single accident** has never been abused.

Like everyone else that has had a similar complaint, I originally blamed the tires and road conditions for my problems. After 6 months I have gone through 7 sets of tires (Out of "scientific" interest - not wear... thank god) and drove all of them initially at manufacturer rated pressure and again with an even decrease in psi from 5-9. Believe what you will, but this is not an issue of improper acceleration/speed/driving. I have had several people drive the vehicle aside from myself, all of whom experienced the fishtailing and swaying to an extent that is unreasonable.

** A parallel question:
In 2004 I was in an accident with this vehicle that did a fair amount of damage to the front driver side. Could any of these "scars" be contributing to this issue?

Since the accident, the front driver side wheel extends outward, exposing the tire some 1.75 inches beyond the fender. This has never given me a problem, nor prevented the truck from being properly aligned.





Compared to the passenger side and a front view






If anyone has any thoughts I would love to hear/read them. Especially if anyone believes (as I do) that the actual aerodynamics of the truck have been compromised to an extent that air flow beneath the vehicle is of an amount and speed in excess of its design, capable of producing increasing lift in the rear of the vehicle. Any takers?

 

I can't believe after doing all that front suspension work that wheel still sits out that far. That makes me think the spindle may be damaged.

As far as the fishtailing.....I had an odd feeling fish tail motion when my rear axle shaft flange was bent. As the wheel and tire wobbled back and worth it caused the truck to do so. It was noticeable in the cab but did not cause any unstable driving issues. It drove fine. The only reason I really knew was people were stopping me and telling me my wheel was about to fall off. The swaying back and forth was about and inch each way. It was very apparent from behind while the truck drove.

 

The fishtailing could just be caused by worn out shocks on the rear.

 

I'd also check the bolt in the center of each leaf spring pack. Normally, the round head indexes the axle perch to the leaf spring. Having one of those bolts sheared off or missing creates a very interesting version of 4 wheel steering.

 

^^^ wouldn't a rear alignment check indicate if that was the case?

 

My guess is frame bent.......... time to trade. 7 sets of tires in 6 months wow.