I have a problem on my LS430 where it feels like a Jeep over bumps. It might as well not have suspension components cause it certainly doesn't feel like they work. My multi link suspension arms (in the rear at least) are old and rusty but the bushings don't appear to be too worn. They return back to where they should be after force is applied, and they don't clunk. The bushing that attaches to my rear knuckle in my rear struts may be shot, but I'm not certain that's what causing this. This is a very similar problem to the guy who posted about suspension issues about 12 days ago, but I made my own thread because I have other issues I'd like to discuss without hijacking his post.


Interestingly enough, I do know at the very least that the coils work because over large bumps, the car oscillates 2-3 times like it should. It's just over the tiny bumps that it transfers very easily into the cab.


For car history:

It appears the previous owner(s) did an entire front suspension replacement, every component looks to be in decent shape. I can't tell if OEM or not, doesn't look too out of the ordinary.

Rear suspension is untouched as far as I'm aware. I am working on it now but I haven't unbolted any bushings (mostly because the bolts are rotted on), so nothing should have changed.

Rims are aftermarket but compatible, size 18 wheels. Michelin Pilot Sport All season Tires 225/55/zr18.


I have a side issue of a pulsating noise that occurs and varies with wheel speed. I believe it is coming from passenger rear side of the car. It is present regardless of wheel speed, but the pulsating frequency increases with wheel speed. I've narrowed it down to the brake rotor (brand new) grinding on the parking brake shoes (also brand new parking brake equipment). I thought this was due to the wheel bearing going bad and having residual play (they don't move at all when shaking with wheel on and the whole drivetrain is silent when both brake rotors are removed, meaning CVs and Diff are silent too), so I am amid replacing wheel bearings. I have videos of the rear wheels when the engine is running and the car is on jacks, and the rear drivers wheel has a little bit of noise and no runout, the passengers side has a lot of noise and probably a half inch of runout. The entire wheel, including brake rotor bounces up and down every revolution, I'm imagining this was causing the issue, but I can't tell if a bad suspension component would also cause it to bounce. I'd just hate to put everything back together and find out this wasn't it.


Here's a video to the bouncing behavior with some commentary over the top lol:
Notice the grinding/whirring noise in the background that sounds like someone flicked a brake rotor.

EDIT: I have also tried the trick that Car Care Nut recommended where you put your hand on the coil spring and spin the wheel to listen for grit. As previously mentioned, there isn't any because the drivetrain itself is silent aside from the brake rotor rubbing.

 

Wheel balancing may be a way to go, have you replaced the struts? I'm having similar issues with mine, where it oscillates fine on undulating roads but small bumps are horrible. From what I heard in my previous thread, it's most likely the struts were just shot as worn-out struts can result in a super rough ride over small bumps but still do fine on undulating, large movements, more so if the previous owner used cheap parts. I've put in some cheap monroes in the front and am having the rears installed next week while I go about sourcing the parts for a full rebuild, will report back if that fixes my issue but it seems to have helped the ride significantly. Have you also looked at replacing the lower control arm bushings in the front? They apparently have a significant effect on the ride and I believe my left side, which rides worse than the right, was replaced with a solid rubber aftermarket unit.

Past that, even without vibrations being present in the shock, that kind of movement in the wheel while spinning seems to me like a wheel bearing issue of some sort.

 

Haven't replaced any struts in the rear and they're rusty enough to look original. The strut bushings that the rear knuckle bolts into look shot and are rusted somehow. I wouldn't mind doing a rear suspension replacement but the capital expense is pretty huge for OE parts. KYB struts are only like 100 bucks so that's not bad, but those springs are crazy expensive. Shouldnt actually need to replace the springs, but I can't tell for sure if I have OE rear struts installed or aftermarket. If the struts are aftermarket,, the springs may be too and then the spring factor is also likely off..

Truth be told I haven't paid much attention to the front struts. I'd imagine they were replaced at some point, but I can double check. Control arm bushings I also believe were replaced when the previous owner did the front end replacement, but again I can double check. It'd be nice to know if it's solid rubber or not, that would honestly be the first thing I'd replace at that point. Those bushings aren't even hard to get.

As far as the grinding sound goes, I'll report back if wheel bearings fix it. I'm waiting on the special nuts lexus uses to bolt their tie rods down with, so it'll be probably a week until I can report back on this, assuming I'm not busy otherwise.

 

You can actually get the OEM parts via amayama for 30-40% less if you're looking to do a full OEM rebuild/replacement, even with tariffs and duties factored in. Not sure what part of the country you're in, but in my experience the bolts on these cars tend to look a lot more rusty from external inspection than they really are, but if you're not sure about the struts, it couldn't hurt to throw in a cheap set of shocks to see if it alleviates your problems.

 

I've priced out a rear tie-rod and LCA replacement from Amayama and it'd be about 550 to do both sides before tariffs. That isn't including springs or shocks, just lower control arms and toe control. Not upper control either, it would have been over 1k if I want to go OEM there. It'd probably be 1700-1800 to do coils and shocks for the rear as well, and honestly at that point, my ls430 has enough rust that selling the old one and paying 2k more for a different one seems to be a better value. It's a ML version as far as I can tell, so no acoustic glass, but has nav and mark lev. No rear massager either, just rear heated seats.

I've snapped bolts (one on the low part of the radiator, one on the driver's rear wheel well holding a bracket for some kind of sensor) and also rounded nuts on this car. The interior is actually in great shape which is why I even want to put work into this car to begin with, I just want to know that with all the time and money I'm putting into this Lexus that it's actually going to be quiet, fun to drive and better on MPG than it currently is (I get 20-22mpg filling with 0%Ethanol 91 Octane. 91 is what is recommended in Lexus Owner's manual, so I use that).

 

I still get around 25 mpg on hwy with half that on interstate on my 2001 using regular gas. As I remember the most I ever got was 26 on premium years ago.

 

I had the same issue with a rough ride over a bunch of small bumps and transmitting through the car. I replaced the shocks with OEM ones, as well as other stuff I needed. This made a huge difference, the car rides so much better. I did a mix of parts from Amayama and buying from Lexus during a 15% off sale. It's still not cheap, but more affordable. I wouldn't recommend KYB aftermarket. I put these on my wife's RAV4 and I haven't been very happy with them.

My shocks were aftermarket as they didn't have any KYB or Toyota markings on them. They were completely dead as they would not rebound at all. Generally you can tell if the springs are factory if they have paint marks on the coil. I had the same concern, but my springs had the paint paint marks on them. Aftermarket usually have no marks. I have the IS lower bushings to put on mine, I just haven't gotten to them yet.

 

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If you don't mind me asking some clarifiers:

1. What speed on average? I get like 22mpg round trip with an average speed of 65-75mph. If I drive 55mph, that's the ideal and I can maybe get like 23 or 24 round trip. But the speed limit is 70 and everyone drives 75-80, so that sucks lol. Yes I use Cruise.
2. What tires? I use Michelin Pilot Sport All Seasons in 225/55/zr18.
3. Is the drive hilly? My commute to work is almost entirely hills with no real flat spots. Even WITH flat spots I'm not getting better than 22 usually (20-21mpg is average I'd say), but there are some pretty crazy hills in my commute. I'd say 2 hills basically force the transmission to downshift to maintain speed. Rest are pretty mild or moderate.
4. What's your ambient temperature? We have winter mix fuel here that does technically contain less energy than normal, but I'm not sure if that applies to premium or not. On top of that, I find most of my vehicles just run 1-2mpg worse in the winter anyways. Maybe it's the fuel, maybe it's the temps. Idk.

I think I may have had more questions but I can't remember them as of right now. I'll let you know as I think of them.

What shocks did you use? Amayama has some Genuine Toyota replacements with P/N: 48510-80130.

Meanwhile, the Bell Lexus parts are P/N: 48510-50120 (and double the price).

 

Regarding MPG, I get 3-4 MPG worse in the Winter here in the Midwest than I do in the summer, so it might genuinely be down to winter fuel blend shenanigans.

 

48510-80130 are the rear shocks and the 48510-50120 is an alternative part number for the Front Shock.
On my '02 I used:
Front Shocks: 48510-80306 (same as 48510-50120)
Rear Shocks: 48530-80130

As for good mpg I have managed to get almost 27mpg on all Highway driving. Last year on a trip from Cleveland to Nashville I was averaging 26.7 mpg. In the winter time don't even worry about good fuel mileage. The winter blends, cold temps, etc. I was generally cruising around 75-80 in 70mph Zones. In every day mixed driving I can really only ever get about 21-22 mpg max.

 

Alright Follow up post:

• My front struts are NOT NEW. This is news to me. They still have the OE sticker on them that says the manufacturing date. I have new rear struts in house and have mounts on the way.
• My front lower control arm bushings are cracked, both sides. Got some new ones on the way.
• With my control arm bushings being shot, I ordered some new lower ball joints as well, those should be here pretty soon.

Wheel bearings don't appear to have solved the problem necessarily but it is quieter at least. I do believe the quietness is due to me substantially backing the parking brake off though. This video from TRQ shows a technician adjusting the exact parking brake system that we deal with on our LS430s: .

I looked online to find what other vehicles share compatibility with our parking brake hardware and found the similar GSs and smaller ISs (2006-2015 IS250) share the exact same parking brake design as the LS430. At 16:34 he spins the wheel hub assembly with it torqued down from the lug nuts and there is a grinding noise that is identical to the one in my video from above. This is the exact noise I was hearing when driving around and it pulses depending on where the wheel is in its rotation. As he describes in his procedure, his parking brake was adjusted too tight and he backed it off and the noise lessened (but didn't go away). I followed the same steps and came to the same conclusion where my noise lessened but didn't go away.

Some noise may remain due to other issues that I'm currently dealing with, will keep posted on that front.

 

Alright I've found a lot more things to be failing than I had expected. My rear struts are absolutely blown, no doubt about it. When you press down the shock rod on the old one and the new one, the new one returns about 3x quicker at 60F. If cold enough, the old one won't return at all lol. Front lower control arm bushings were blown too, inside was a nice orange powder (dried oil) instead of just normal oil. Work has a shop press, so I got the bushings from Amayama and got that done. Front Lower ball joints were worn but not necessarily bad, but I had the new part on hand so I replaced them anyways.

I found that the major rust on my LS430 is actually on the Subframes, not necessarily the frame itself, which is a relief as this is somewhat easily removed. The rear pinch welds in front of the rear tires are unbelievably rotted, but everything else appears to be surface rust for the most part. I've been dealing almost entirely with rust for the past month or so, and haven't driven it yet since I've replaced everything. Will post here when I do.