2004 UL LS 430 with 115K miles. Recently replaced items related to the suspension: Michelin MXV4 tires, Lower control arm bushings, tie rods, assembly rods, new brake front brakes with rotors, steering rack bushings. The noise was there before and after all these replacements. I checked and double checked every nuts and bolts on the bottom of the car.

Here is the symptom, I have a rumbling or more like a drumming noise coming from the front left (driver side). The noise is very noticeable on bumpy roads while going from 1 to 25 MPH. It probably appears at higher speed but I don't notice it. TIA.

You'll notice on the first video the rumbling begins at 8 sec and became very loud after the bump til the end at the stop sign.

On the second video the noise appears from the beginning and became very noticeable beginning at 14 sec. It became much louder right after the bump.

 

your engine mounts may need changing.common on our cars.

 

That maybe the case but I doubt the engine mounts play a part with the noise I'm having. The noise persist with foot off the gas pedal. I'll check the engine mount thou.

 

Strut bar bushings? Sway bar links? Just got to go through it. Look for play in ball joints and or wheel bearing by seeing how much play there with the wheel still on. Find where it's moving and vibrating.

 

Which one is the strut bar bushing for air suspension?

 

There isn't a "strut bar" bushing. Basically any wearable part can be suspect. Since you've replaced most of the usual suspects I'd be inclined to think its a wheel bearing. I couldn't hear the noise on your videos, but usually a drumming or grumbling noise is a wheel bearing. You may also want to check to make sure the end links are installed properly, I just found one on my car that was installed on the inside of the sway bar flange instead of the outside, without a retaining washer, and the link eyelet had popped right off the rubber bushing and was bouncing around. Seems like I always have to triple check anyone else's work when they touch my car.

 

I was finally able to hear the noises in your videos. Funny thing is, I have the same problem with my '02. I replaced everything in the front suspension a couple years ago and have noticed this noise for quite some time. Techs have since told me everything was fine including the wheel bearings. Frustrating to be told that when you know something isn't right. Feels like the top of my air shock isn't bolted in tight or something, drives me nuts too. It's only a problem at lower speeds, isn't noticeable at higher speeds. Like you I just checked all the suspensions points with a crowbar for any looseness and couldn't find anything, that's when I found the messed up end link on the passenger's side. Unfortunately fixing the end link didn't solve all my noise issues with my front suspension. BTW I have a nasty clunk coming from the front right over bumps at slow speeds, its completely different than the sound from the front left, and this time it's for sure not the end link.... always somethin'.... grrrr

 

FYI one other thing to check is the torque of the control arm bushings, make sure they are to spec. I believe the front one is 166 ft lbs and the rearward one is 100 ft lbs. Do not overtighten the rearward one or you'll strip the stud requiring you to get a new control arm. If the front one is not to spec it'll make that noise you have, and even though it may feel tight, if it's not to spec it won't be tight enough.

 

Thanks Ancdmd for your suggestions. I have read almost every thread in this forum regarding noise for the last month. I have ruled out wheel bearings or any loose screws or nuts. I will replace end links and the rear stabilizer bars soon as they are showing signs of wear. The other culprit might be the left front air strut.

 

I should mention, on the LS400 forums we always referred to the part at the strut bar bushing. This was almost always the part that give you the clunk or pop on rough road. I know the ls430 has something similar. What the part is called I can't remember. Maybe it's integrated with the lower control arm now. Did replace 4865550012 BUSHING, LOWER ARM, NO.2 and the whole lower arm?



https://www.clublexus.com/forums/ls4...er-thread.html

 

So the strut bar bushing is the same as the LS 430 Lower Control Arm Bushing, correct? I replaced the lower control arm bushings (48655) about a month ago.

 

There's two in there. Check the other one out. I think you have to buy the whole arm.

 

Yes the forward bushing and arm come as one unit.

 

Lavrishevo LS 400 link leads me to the LS 460 control arms issue https://www.clublexus.com/forums/ls4...trol-arms.html. Apparently control arms failure are very common on the early LS 460. The began failing as early as 40K miles. They cost around $4K at the dealer.

 

May be your wheel hub bearing(s) are going. My drivers side rear wheel hub bearing made similar low growling sound, then went into a grinding/metallic sound. Put the car on jack stands and sure enough, the wheel could be wobbled by grabbing it and moving it back and forth, and turning the wheel hub made a similar growling sound.. Just put on new SKF BR930294 rear wheels hubs on both sides (which have Koyo bearings BTW) and no more noise. At least worth a look in your case.