SUV suspension question - SWAYING!

I have a 99 4runner... I put more into it than I should, but oh well, I almost have it perfect, but there is one last issue.

I have replaced the majority of the suspension, but it sways pretty bad at highway speeds. I replaced the sway bar end links because they were very worn, which helped, but it's still not correct.

It just kind of dances on the highway, and doesn't feel very planted. It feels like it seasaws corner to corner, and it's a pretty silly ride. On a perfectly flat road it's perfect, but this happens when you hit bumps... It has new shocks, and coils, but it's almost as if this is overpowering them...

Does anyone have any experience with this, and maybe what it could be? I really just don't want to continue to throw even more money at it...

I've been looking at this on the 4runner fourms but it seems as if no body posts the results of them fixing it! I don't expect it to be perfect, but it's driving me bloody crazy.

I figure this place as always is the best bet!

Thanks

PS... If it helps... You can tell there is a change when you left off the gas, than when you are on it... Not sure what that means, but it's happening.

 

What tires are on it?

 

Firestone Destination

 

Don't know about those in particular, but wandering around at highway speed can commonly be attributed to tires.
Aside from that, you could check the ball joints and steering tie rod ends. It could also be the steering rack bushings. I know that is a common thing on the older Tacomas to go out, and that can cause a wandering issue.

Check this thread - it appears the 99 4 Runner may be the same as the 1st gen Tacomas. http://www.yotatech.com/f2/steering-rack-bushing-replacement-169316/
Not too difficult, just time consuming.

 

I do not know what rear suspension it uses, but if it is a trailing arm/coil spring setup,then check trailing arm bushings as well as the panhard bar/track bar.

 

I tried some Kumho tires on the Suburban once, they were horrible in a way just like you describe. Ass end of the truck was all over the place, twerking down the road.

 

I'm not sure... I should really know more about trucks.

But it's a solid rear axle with springs and shocks, but not a coil set up like the front.

I have replaced the ball joints... and i'm fairly sure i've replaced the tie rod ends as well...

I'm hard pressed to say it's tires becuase it's only on bumps really... and it makes the whole suspension move... can tires do that?

 

Yes. A shitty tire will make your life hell. Especially something with a huge sidewall on a 4 runner. It probably flexes way to much and it makes that awful swaying that makes you feel sea sick

 

Another thought, I once had an alignment done when I got new tires and they did a terrible job- it swayed all over the place. I then took it to another shop for an alignment and then it drove like new.

 

Does it have a shimmy shock?

 

this right here indicates a too much lateral movement in the rear. straight axle may have a panhard rod/bar, if it does then those bushings need replaced. if it doesnt then whatever bushings control the lateral movement.

push the body side to side while looking at the bushings to determine which bushings are bad.

 

No shimmy... just like a sea sick motion side to side.

I will check out the bushings tomorrow. Hopefully it will be something easy. I would like to try that before I put new tire$ on it.

 

Steering stabilizer.

 

yeah, not enough "toe in" in the front can make it unstable too but it wont change with accell/decell.

I can eyeball it and get better results than most "shops" with high tech sophisticated alignment machines sometimes I need to result to some string and a tape measurer y'all probably think Im full of it, eh?

learn these tricks watching G. Morretti's (MOMO) crew fine tune the 333SP at Daytona years ago. I was sorta shocked to see the way they set up that machine with all the gizmos they had available.

 

What we used to do with the offroad VWs, set the front of the tires 1/4 inch less than the rear of the tires with a tape measure.

 

Usually it is the other way around that causes instabilityToo much toe in will cause the vehicle to be darty. Toe'd out is normally pretty stable, we run a Half inch out on the race car...

Anytime you change the load on the front tires it can change the stability of the vehicle.
If you are carrying a big load you really need to get it aligned with the load in it.

There was a service campaign where the rear springs were replaced years ago...
Might need to make sure it has been done.

 

We always ran between a quarter to half inch Toe out on the midgets, closer to three quarter to inch on a winged sprint.

 

1/4" toe out? damn that car autta drive itself! LOL its probably got a stagger to it also right?

from my experience (RWD Only and mostly Italian jobs) toe out and you get that following the bumps feeling or wandering.

racecars are a different animal. throw away the "specs" and adjust to suit the race.

 

Depending on the track we would run upwards of 8 inches on the midget and more on a sprint.

 

I am guessing on the street car you have some bad bushings or funky tires.