this sounds like it is in the dash (it is that loud) you hear it when the left front wheel hits a "pothole"

I am thinking it is the front coil spring BUMPER, part number 4833150060.

In the photo below it is 48331.

MY QUESTION IS has anyone had to replace this item on your LS?

Sewell has 5 of them in stock, so it must wear out.

 

I'm thinking it is an upper control arm - part number 48630-59015 - check the ball joint in the center of this part

otherwise, I vote for the shock/strut itself p/n 48510-59106

that could be their original stock and none have ever sold!

I would call and ask which front uspension parts sell the most

 

No real comment on your diagnosis.

But to answer your question, I did replace these on my '91. I did all 4 corners with KYB struts and strut mounts and Genuine Lexus on all other parts. On at least one of my struts, the bellows thing was torn away enough that I could inspect the bumper with the strut still on the car (jacked up, wheel off). It is a very tough looking plastic piece (not rubber), and I could see that it was intact but kind of chewed up. So I think I replaced all 4.

For the overall job, I know I replaced a lot of parts that were original and still very good at 170k miles (e.g., the strut mounts seemed just fine but I had the replacements so I just put them in - not worth it to return).

My thinking on these bumpers is that they are not supposed to ever be touched. They are a last-ditch buffer in case the strut has failed or you're landing big jumps (that was a joke). In normal driving, potholes, etc., with a functional strut, I don't think the bumper should get hit. So if your bumper is chewed up, broken, or gone, then your strut is probably bad too.

You can try to inspect it without removing the strut, but may not be able to see in there if the bellows is fully intact. The bumper is a dark orange plastic thing, as I recall.

 

thanks guys, I forgot about UCA bushings, and it could be the strut, this 99 has 236k.

 

My 98 LS has a few front suspension noises and I've solved some but can't find out what others could be. I've been researching older posts for more information.
Did you find out what was causing the noise in this situation?

 

When you press down on the front of the car does it bounce more than 1 1/2 times? If so, thinking struts. Is there abnormal tire wear? A bad strut can cause bouncing tire wear faster than the opposite tire. Clunking on speed bumps or the like leads to ball joints. Jack the car up. Grab the tire at 12 and 6 o'clock can you shake it? What about at 9 and 3 o'clock? Struts are expensive and you have to do them both at the same time plus an alignment. You are looking at $600+ if you need struts. Ball joints are most likely to last thing to go. I would suspect, sway bar bushings, sway bar support bars, tie rod ins and out, struts, and then ball joints lastly. Also, not sure but there might be grease fittings in the suspension. You might just need sway bar bushings and a suspension greased.

 

Oh I've been at war with suspension noises since I got my LS last year. There's also persistent wind noise which I attribute to a replaced windshield. I replaced the strut rods altogether and that stopped a loud clunk while hitting bumps or inclines. I also replaced a leaking steering rack and outer tie rods which helped steering feel. I just ordered KYB struts off Rockauto for a ridiculous low price. They had some closeout deal going on. I will have those replaced along with the mounts, bumper, and insulators. I just can't determine whether to buy OEM front strut mounts or use KYB. The OEMs are like $130 a piece. The rear OEM strut mounts are around $30. It is weird because each time I solve a suspension noise another one appears. Right now I have two different faint sounds. One is an occasional burst of creaks when turning slow (think Ford Crown Victoria) and another is a single slight knock when steering at slow speeds. I can swear both these sounds started when I asked the dealer to tighten the strut bolts and other components. It was then the dealer mechanic concluded I needed new shocks. The car doesn't really bounce but the handling isn't on point and I suspect worn shocks not keeping the tired planted to the road. I don't service the car at dealer but really wanted to get to the bottom of the suspension noise and they were mostly useless.

 

Noises with turning I would be think steering rack, too. I saw a write up on how to flush clogged screens in the rack and pinion selanoid that didn't look too difficult. But I would check to make sure all the plastic under panels are secure and tight first ... they can mimic suspension noise. Also, rocks can get up into panels and make noise. Drive on gravel roads or driveways?

 

Loose battery mount? Broke fan shroud? Loose radiator maybe?

 

I suspected it was the steering rack but when I had the whole thing replaced the noise remained. It is most definitely a suspension component. I just know it but can't zero in on which part. I'm not going to actively pursue investigating as much anymore. I will replace the shocks and mounts in hopes it may cure the problem otherwise I'll live with it. The lower ball joints were said to be fine. Thanks for your input.