Update: Well the clunking is back in full force... It all started with a simple "R" inspection sticker for a Lower ball joint. I've since changed the upper control arms, LBJ's and tie rods+end links. This was done progressively....I tend to look things over if I do too much at once. After every single test ride the clunk seemed to disappear, but then came back after about 50 miles. Although the shocks have 99k, they don't bounce or leak. I am suspecting the upper strut mounts on both sides.
I'm like C'mon HuH?!!!! Someone gimmie some pointers!! LOL .. I don't mind changing out the parts cause we have a new owner waiting patiently. That's a couple years away....right now, I just wanna find this clunk!!

 

Since you have already change the UCA and the LBJ. Nothing else would make a clunk afaik. do correct me. does it happens when going fast or slow? are you sure it's not your shocks bottoming out?

 

What about the Lower Control Arm? I'm curious, because I'm having the same 'clunk' on the left side of my car, at slower speeds going over bumps, at highway speeds it's fine.

 

Tie rods and bushings?

Someone posted that as a solution a week or so ago.

 

Yeah, i get the clunk when going over bumps at 30-50mph....and it's getting louder and more frequent. I've already thrown money at it, so I can't stop till it's fixed. It's got to be the front shocks, or the strut mounts. It's all stock with no mods except gs400 17's. I think I will try one side. If it still does it, I'll have to go to a lexus mechanic/stealer and let them handle it.

 

Bad bushings will definitely make a clunk sound

 

tension rod/caster arm/lower control arm no2/whatever the hell you wanna call it?

 

Shocks were the first thing I tried on mine, car had 180k, but alas, the clunk didn't go away.

 

Mine won't clunk with the brake pedal depressed - even barely depressed makes the clunk disappear completely. Makes me think my clunk is brake-related, but the shop swears they're solid and not the cause. Opinions?

 

Then the pads are moving around.....is that factory shim kit still installed on your brakes? Check the torque on the caliper bolts too. I know cause I checked for this already and all was good.

 

Really? When u did the shocks, did u use the old strut mounts with the new shocks? Damn, it seems like there like 1000 fixes 4 this common problem. There's just gonna be a "replace everything" answer. LOL

It's a crap shoot....when I do finally get it fixed, I will post back....

 

I used the old strut mounts, but I can't see how that could be the issue because it looked to be in good shape.

 

GOOD LUCK. i have been battling this same issue for a year now. my "clunk" is from the rear and feels like a baseball bat hitting my back seat. only happens when the suspension unloads. like when going over a bump and the car gets light feeling, then- boom! never found marks , dents, or evidence of any kind of unwanted movement.....

 

Mission accomplished! Bye bye clunk. Turns out it wasn't suspension-related at all.

It was a "slider pin" on my front passenger side brake. I'm no mechanic, but this is how it was explained / shown to me. There are two slider pins - which look like really long bolts - that are used to hold the brake caliper in place. One was not OEM and was slightly small, which allowed for the caliper to bounce around. And it was an inexpensive repair all things considered ... then again, the 90K mi service done at the same time was anything but inexpensive.

No idea how it got switched out or broken, but I wonder if it happened the one time I took my car to an independent for front brakes. They didn't use the shim kit and it rattled big time. The dealer fixed me up at that time, but I wonder if that shop buggered the slider pin at that time. Who knows?!

On a similar note, my lower and upper control arms, tie rods and bushings are all in fine shape. Knock on wood.

 

Nice find!