99 4runner limited rearend squirrly over bumps??????
 

I have replaced entire frontend. upper lower control arm bushings, innner outter tierods shocks steering rack bushings and upper lower ball joints. It feels very unstable over any kind of bump in road over 30 mph. I had a friend who is 250 pounds sit in back while i was under the rig. the coil springs are compressing all the way down to the cone bumpers inside the coils, Would this be my culprit? bouncing off of the cones and throwing my rear end around? Not alot of play in any of my rear control arm bushings and the panhard bar is tight. It gets very iffy on the hwy.

Weird that this is my first post, I've been a member since 2012...LOL. I search alot and always find the answers I need. Finally caught one new enough to give my input. Anyway, back to your problem.

In the event I am wrong someone please set me right.....In my experience if everything is mechanically sound on your vehicle and the rear wants to come out from under you it is usually a weight problem. Like when a trailer is loaded improperly (all the weight in the front) and it shakes back and forth at higher speeds. Try adding weight in 100 pound intervals to the rear compartment as far back as you can until it stops. That way you can estimate a weight for a more permanent solution. Rear bumper, Spare tire mount, etc.

Do you have a heavy bumper, with or without a winch, installed in the front? Not alot of info on your profile.

The only other thing I can think of is the alignment is off. I would be at a loss if it were anything else. Looking forward to the answer because you and I have the same rig.

My 2000 does the same thing and I think you are correct in that it is the sagging springs.

The 2000 sits really low so there is not much distance between the bump-stop and the axle. My 1999 sits much higher and does not feel the least bit squirrely going over bumps.

the runner is all factory no aftermarket bumpers etc. no winch. shouldnt be that much of a weight distribution problem I wouldnt think? Or most all 3rd gens would have the same problem. Im not ruling out at adding weight would help, Im just thinking somethings not right.

looking at the runner it does not seem to sag visually. but i can push down on rearend and feel it bottom out.

How old are the rear shocks?

As far as I know shocks are original with 267k

Check your rear upper and lower control arm bushings.
Hit the arms with a rubber mallet or dead blow hammer and see if they move around at the joints.
Or just try and move them with your hand.

They're probably not doing much damping at this point. The 4Runner has a live axle, with very heavy wheels and tires. That's a lot of unsprung weight. When you hit a bump, it bounces the axle and tires up. If your shocks are good it sets down again and stays planted. If they're shot, they bounce a couple of times.

The rear springs could also be sagged, it's a fairly common issue with 3rd gens. The rear end gets saggy. Really, new springs and shocks and check all the bushings and it shuold be back to as-new again. Needing new springs and shocks is a good excuse to put a lift on it.

18 years of sag and it's time for new rear springs. My '99 looked fine unloaded, but add in the slightest weight or go over a bump and it would hit the stops. New shocks were little help. New OME 906s and problem solved. Go great with original '99 talls in front.

Agree with TheDurk....Change coils and shocks and see what ya got. Sorry guys, I assumed his rear suspension was looked at and deemed good to go.

Thanks guys gonna change the coils and shocks then the rear bushings. Are the moog coils acceptable I'd not doing any towing? Also any good shocks cheaper than the 5100s or should I just go ahead and get them

I'm using FJ80 Tokico (OEM) shocks on mine, but that's with a ~3" Sonoran Steel lift. OEM shocks last 150K miles, they're plenty tough.

SS used to supply 5100 shocks with the lift kits, my wife had that on her '96. They lasted a disappointingly short amount of time. Something like 50K miles(?). The 5100's in the front had to be replaced sooner than they should have as well.

Good ol days of suspension talk.

OME 906 is great. X2 on that. I still run orig shocks, but don't stop there. Once you're through with the rear, you'll be back to the front for the rest of the upgrade. It will 'sag' in the front until then.

Heard mixed things about Moog, but I don't think you'll go wrong. Base whatever you choose on your needs. Who knows, you may wanna tow later (if you got a hitch). You can load stuff in the back and so on. There's quite a few options and heights. But beware of how much change in ride height. Its not the only thing that changes (drivetrain, tires, etc). So the 'upgrading' might continue. It can make your wallet a bit lighter.

Have fun, but please give us something to look at in the meantime:)

I'm a big fan of Moog parts. That's the only brand of steering system components I have found that will hold up in my log trucks. They take a beating they were never designed to. Never had any of their springs but I trust their quality.

Blistein and OME are arguably the best shocks for our trucks, however, I have run cheapo Monroes in my 01 and was very satisfied. I am currently running the ones that came with my Rough Country suspension kit. They are fine too. Beware though, the top shock nuts are absolutely awful to remove and install. Don't put shocks on there that you think you may have to replace again after a couple years, You'll see what I'm talking about soon enough. Best method I have found is a 17mm deep socket and a 12" flex handle 3/8" ratchet. Somebody correct me if I'm wrong here so he'll have the tools he'll need.

Was wandering if this fixed your problem.

New coils and shocks same problem still persists. Not really sure what it Is unless indeed the bushings in control arms are causing this

So then what do you mean unstable going over bumps at higher speeds? If its the entire truck, yeah, maybe needs alignment, like one of the earlier posters said. Esp if a lot of front suspension work was done.

If its the rear only, can you go into more detail, since now you're saying the problem persists, even with new shocks and springs? Curious to know what you went with, though I doubt that makes any difference.

Unstable could mean a lot of other possibilities...even something as simple as lug nuts not torqued...or worn tire treads...

By squirrly I mean the rear end feels like it kicks out to either side over a dip or a bump in Rd going 30 plus mph. Moog springs kyb shocks. Does ride a lot better but issue is still there.

Marc suggested rear control arm bushings or something...maybe check those. Or perhaps rear sway bar bushings/ rear end links...they're involved with controlling the side to side movements...