Trying to figure out what to change to tighten up 99' tall stock 4runner suspension.

Handles well in absence of bumps, no excessive roll in corners, no dead zone in steering. But when faced with a big bump, rear has a tendency to wander badly side to side and cause a feeling of severe sloppiness. At it's worst when faced with a series of rough bumps on highway, it has caused almost a full unwanted lane change.

Shocks are old but don't seem to allow excessive bouncing over bumps, so I don't think its the main problem.

What can I change? Ideally I have some part numbers I could bring to toyota and then have my mecanic install everything.

Thinking theres worn bushings some where in the rear

 

Just how high of a lift ??

The higher you go the worse it will handle.

Then depending on just how it was done you might have to much spring for the weight of the vehicle making it bounce like a pogo stick.

Slow Down!!

If you have worn parts they should be replaced without being up close and personal hard to say if it will help.

 

It's bone stock '99 4unner SR5, so has the '99 tall springs. I don't know how much higher it is then other years, maybe an inch or two max.

So could somebody list all the possible toyota suspension components that I may have to replace? At least in the rear, I think that's where my problem lies.

 

So first thing I would check is your panhard bar and make sure it is tight.

Then look at your sway bar. Are the bushings worn? What about your sway bar links, again are the bushings worn?

Then look at your upper and lower rear control arms. How do the bushings on those look to you?

Those would be where I would start if you think the shocks and springs are good.

 

Awesome, that's what I was looking for, some good troubleshootings steps.

Can I just grab the panhard bar by hand and feel for play?

Pretty sure my rear sway bar link bushings are not in the best shape (maybe even cracked), I'll have another look. If those are done, could that be my issue alone?

I'm not sure how to check the UCA and LCA bushings, can I just inspect visually?

Thanks!

 

Pics of your rear suspension components help.

Put the truck up on jack stands at the frame so the rear suspension is off the ground and start wiggling parts. Crap will feel tight with the weight of the truck on your axle

If your mechanic knows what he is doing he should be able to inspect it and show you what is bad with the truck on the lift

 

Pretty easy to remove the RLCA though and have a look

 

If the ride height is much taller than normal, then the panhard rod will be moving the truck somewhat to the side when the whole suspension compresses (vs. just one side compressing).

It's a simple but imperfect method of aligning the rear axle side to side and still allowing independent movement of the axle. In a perfect world, the panhard rod would point downward slightly, then when a bump compresses both sides it would lengthen slightly as it became level, then shorten again as it went past level.

With a lifted suspension, it droops even more, and as the suspension compresses it mostly just gets longer and pushes the rear end in the same direction the whole time, this is felt as a squirm, or as sloppiness.

The real fix is to raise the axle's panhard mount position by as much as the suspension's normal ride height is over stock geometry. or just ignore it.

 

Update:

I lowered my rear tire pressure by 5 psi until I have time to properly address this. My D-rated Geolandars were up around 40 psi, which was evidently too high (was trying to sqeeze as many MPGs as possible since I drive mostly street). The difference is astonishing, I now experience the issue WAY less. I guess the tires are compressing more over bumps now, so the suspension doesn't have to travel as much, and therefore the panhard has less of an effect. I also realized my tire pressure should generally be less in the back since its a front-heavy truck. Probably should do a chalk test to really get it dialed. In any case, thanks for the comments/advice everyone.

 

The husband's also got a stock suspension 99 with 200,000 miles and it handles pretty much as you describe-
"Handles well in absence of bumps, no excessive roll in corners, no dead zone in steering. But when faced with a big bump, rear has a tendency to wander badly side to side and cause a feeling of severe sloppiness. At it's worst when faced with a series of rough bumps on highway".
Bumps on a curve on the highway are the worst.
He's also got seriously worn out shocks.....
I could see how that coupled with high tire pressure would exaggerate the goin' that-aways travel on bumps.
Though certainly the old thing could do with a twice-over on all the rubber mentioned above don't discount the possibly shocking state of....shocks.

 

x2 on what habanero said. with the shocks having limited control over the coil spring actions when it rides over a bump, there will be a feeling of sloppiness