Ls400 Strut Bars,balljoints, Noises,clunks

[rfworld]

Many threads have been written on LS400 suspension problems. There are pictures and step by step guides to remove and replace the various arms, joints and bushings that can all cause noise and steering issues.

What the DIY er who does not want to replace every component in the front end at a huge cost needs is a test guide to determine which components are the real culprits. Hope this helps...

Here are the front end components and their approx prices purchased online. Price are for Lexus OEM

Strut bars complete 100.00 x2

sway bar bushes 20.00 x2

sway bar end links 69.00 x2

lower ball joints 75.00 x2

tie rod ends 50.00 x2

lower control arm 200.00 x2

upper control arm 250.00 x2 cheaper if you don't go OEM

shocks(strut cartridges) 100.00x2

strut mounts 50.00 x2

upper strut umbers 20.00 x2

Disclaimer... roughly going off pure memory as to what I found online so prices may be some what different" ball park"

So we are in the neighborhood of about 2000.00 in parts and a lot of DIY hrs to replace everything and hope that your LS400 is now good for another 100,000 miles.

Inspections

Strut bars

With car up on stands and front wheels hanging and wheels turned to limits shine intense light into both sides of each of left and right strut bar bushings AKA "bushes" and see if cracks turn into tears as you rotate and elevate the wheels. These tears and cracks will cause not only thumping but instability so much that the LS will drift more on windy days. Driving over crack and sharp bumps IE RR tracks and manhole cover plates will cause the LS to bang and shift position off the impact. The impact noises will travel through the strut bars and up the steering knuckle and resonate in the shocks leading the driver to believe noises are coming from other components and locations. Pops rattles and other annoying sounds,vibrations.

Ball joints

The tie rod ends, the lower ball joints and the upper control arms all contain ball joints that will wear and cause vague feelings of drift. When these ball joints get to the point where they not only have lost their firm socket resistance but are now able to move vertically due to the ball and socket being cracked the LS will jump on small rd bumps and make banging noises that can also travel and resonate through the front end misleading the diagnosis. Pull the joints apart using a 25.00 puller from pep boys and compare to a new joint for what a tight feel is like. IF gravity can get a joint to flop over it probably is done. Do nOt use pickle fork or you can kiss that ball joint rubber cover good bye.

The sway bar links have small joints on each end and while they probably won't make banging noises they too can become limp and take away from the sway bars job which is to keep the LS stable during turns.

Upper and Lower control arms bushes these bushes are hard to inspect while in place. If you use intense light can see tear outs in the bushes replace. If you place a large screw driver or pry bar under the arm where the bush is installed you may be able to move the bushes enough to see tearing. If you cannot let your wallet be your guide as you leave these two most expensive parts as last inline on the elimination process.

Strut cartridges or shocks. If you do the basic bounce test where you press with all your weight on the corner of the fender and the car does on bounce and returns to normal you are probably okay. Inspect with intense light the cartridge for oil leakages. Excessive leaks mean a replacement no brainer. If you go for new cartridges get new bump stops inside if they are dried out and check the strut mounts for worn out rubber or corrosion or dry rot. It is too much work to skip over these additonal parts if there is any doubt after visual inspection.

Sway bar bushes. Replace at 100,000 miles no brainer as they are relatively cheap and easy to install. remember to grease , white lithium okay on inside of sway bar bush to keep squeaks to a minimum.

Removal of all above parts will need various techniques. Certainly a two foot breaker bar will be needed to influence the stubborn hardware. Try soaking all hardware days in advance with your favorite IE liquid rust, WD 40 ect. A baby hand sledge will help as will various pry bars. One particular stubborn bolt can be the lower shock bracket. this bracket fastens with two bolts. The problem bolt can be the small bolt that fastens into the lower control arm. It is short and may be frozen. It is a good idea to order two of these bolts before you start and grease with anti seize for future removal. If you cannot get this 17 MM to turn carefully apply the torch so that you do not burn the nearby brake lines or wires for break wear or ABS. If you strip this head off you might seriously think about replacing the lower control arms all together as you will be dealing with drilling easy outs and other very difficult processes that may end up destroying the threads in the lower control arm. Your best bet is to heat that sucker cherry red before you even make your first crack at it with the breaker bar. DO NOT USE THE IMPACT HAMMER!

Bushes that tear , stretch and move can also create enough "jar" in the system to make the ball joints reach their limits which will create additional metal to metal banging noises. Strut bar bushes can somewhat sling shot or whip your front end on bumps and your LS will get a nasty whip in movement in addition to horrendous noise. Research leads one to believe that the strut bar is the number one culprit in cars that have reached 100,000 miles that are still on the orginals.

The sway bar links also can be very stubborn to remove. They also have 17 MM nuts on those ball joint ends . Heat them with a torch once you have committed to replace the links to get the nuts to crack and move. Then use you Allen wrench to hold the inner thread while you back the nuts off. PITA !!!!

More additional savings if you mark your geometry with a sharpy you will save on a 100 dollar Lexus alignment.

If you pay Lexus to replace everything above at 100 per hour plus 50% mark up on parts over places like Iron toad you're looking at possibly a 4000.00 job. DIY 2000.00 Find the real culprit and replace only that and you might get away with 200.00 plus some !Removed! knuckles. Of course more mileage will eventually cause all these components to fail and here you will sit again in the front wheel well.

Every component wears over time and each ones small looseness will add to a larger cobined loosness in the front end

REPLACE EVERY COMPONENT IN PAIRS! in other words replace the left and right side strut bars!

Hope these observations help you. Check out his link for a great pictorial.

rfworld

98 LS400 black

08 Corvette coupe black

05 Accord EX silver V6 for sale

05 Highlander

contact me direct Dave

rfworld@aol.com

This info is for a 1997 LS400, probably the same as yours, but check.

Hi, replace both strut rods, The strut rod part numbers are 48670-40011(LH) and 48660-40021(RH).

They come complete with bushings and 2 pressed-in bolts.

they run about 95 each.

http://photoshow.comcast.net/watch/Fj9WH6CM

[oarnura]

Thanks for that informative post.

My problem is slightly different. When I hit a sharp bump even slowly I can feel it quite a bit in the steering with a soft clunk. It doesn't feel like a worn bushing. Otherwise I get no drifting or problems in turns.

What component would that be a symptom of? The car is a 98 with 84000 miles.

[landar]

Thanks for that informative post.

My problem is slightly different. When I hit a sharp bump even slowly I can feel it quite a bit in the steering with a soft clunk. It doesn't feel like a worn bushing. Otherwise I get no drifting or problems in turns.

What component would that be a symptom of? The car is a 98 with 84000 miles.

Mine did something similar to yours. A clunk when turning into the driveway and going over a slight curb (like a speed bump).

And it only did it in one direction, not the other. I replaced both strut rods last year and the problem went away. Mine is also a 98 LS400 which

had 68k at the time. The rubber bushings get dry rotted and cracked over the course of 10 years.

[rfworld]

Thanks for that informative post.

My problem is slightly different. When I hit a sharp bump even slowly I can feel it quite a bit in the steering with a soft clunk. It doesn't feel like a worn bushing. Otherwise I get no drifting or problems in turns.

What component would that be a symptom of? The car is a 98 with 84000 miles.

You need to inspect the individual components as well as moving the parts for excessive play.

[oldskewel]

...

Pull the joints apart using a 25.00 puller from pep boys and compare to a new joint for what a tight feel is like. IF gravity can get a joint to flop over it probably is done. Do nOt use pickle fork or you can kiss that ball joint rubber cover good bye.

...

Great information. I've filed this away. Thanks!

I'd like to echo that suggestion on not using a pickle fork. I've seen many instructional posts that say you'll need new tie rod ends when you replace the lower ball joints, just because the pickle fork will ruin the rubber. Not true. When I did mine, I used a screw-type puller that worked perfectly, probably easier than a pickle fork, and the perfectly-good tie rod ends were re-usable.

Ed

[GearHead28]

APXautoparts.com sells the 1990-1994 and 1995-2000 LS400 upper control arms for $100 each including free shipping. I replaced both of my fronts with the APX part six months ago and it fixed my clunking issues.

[Micah.Berry]

Thank you for the very informative post. I've bookmarked it.

Micah

[stevie boy]

Okay, I've read hundreds of posts in multiple forums regarding a variety of loud knocks heard whenever the LS 400 suspension encounters a sudden, perhaps even small (1-2") rise in the pavement, even though the suspension makes no other sounds during more gradual excursions, and dampning is good. Some suggest replacing both front struts, some say replace the rubber "spring cushion" at the very top of the strut, others swear that the strut rod bushings are the culprit. My car makes no noises when physically bouncing the front suspension by hand, or during hard breaking from slow speed, and using a large (6 foot) pry bar, I can not create any front-to-back movement in the front wheel when raised slightly off the ground. Therefore, I believe my problem must be related to the top strut mount, specifically the rubber spring bumper that cushions the strut shaft in the top mounting assembly. I have seen pictures that identify it as a "spring bumper", but I do not have a part number. Does anyone know the part number for this item? Thanks

Steve

[stevie boy]

Okay, I guess I should have said that I suspect a defective upper strut mount assembly; does the rubber shock isolator inside wear out, allowing a metal to metal contact during quick compression? I know that my struts are not bottoming out, so you are right about the "bumper" not being the problem. Thanks,

Steve

[billydpowell]

will this help? 1st gen and 2nd gen...( the strut rods are different)

comp1.pdf

[oldskewel]

Okay, I guess I should have said that I suspect a defective upper strut mount assembly; does the rubber shock isolator inside wear out, allowing a metal to metal contact during quick compression? I know that my struts are not bottoming out, so you are right about the "bumper" not being the problem. Thanks,

Steve

(all of this is based on the front suspension on my '91, but from Billy's post, it sounds like it's the same for you)

To clarify some of the relevant parts from that drawing, for those it may help ...

Part 48755 in that Sewell drawing is the "strut mount". I replaced mine with KYB part KYSM5176. The part above it (48553D) is just a cap. The "insulator" (boot, bellows, 48257B in drawing, 48157-50010 for my '91) is below it, with the top of the insulator providing a rubber cushion between the top of the spring and the bottom of the shock mount. The lower part of the insulator obviously tries to keep dirt, etc. off the strut. The "bumper, front" (48341 in drawing, 48331-50010) stops the strut from reaching its end of travel.

If the insulator is intact, it may be hard to inspect the bumper without removing it. My bumpers were kind of chewed up and I replaced them. I can see that if the strut is not providing the damping it is supposed to, then the bumpers could get destroyed, and the strut could be hitting its end of travel, making a bad noise. I don't know if that's your problem.

The strut mount (as it sounds like you figured) is made of two thick steel plates with rubber in between. Not much rubber by the way, I'd guess 1/2-3/4" thick at the thickest point, much less at the thinnest. Mine were completely intact, looked perfectly good, but since I had the new ones bought I replaced them. If this rubber were to separate, then yes, you would hear clunking sounds. If you read the KYB (et al.) propaganda, they'll tell you to always replace the strut mounts when replacing struts (at 50,000 mile intervals, by the way). So I guess they ARE considered a wear item.

By the way, I did all four wheels, with KYB struts and mounts and Lexus everything else, and it rides great. I don't understand some comments you'll see around here that say the KYB ride is too harsh.

[VBdenny]

One of the most informative posts I've seen in awhile. Thanks.

[stevie boy]

Well, I ordered motor mounts and strut rod bushings; should know if they fixed the engine vibration and clunking sounds (two different problems) in a week or so. If it still clunks, strut mounts are my next project. I know they are the least probable cause, from all the comments I've seen, but my gut tells me different. I'll let you know. Thanks for the info.

Steve

[billydpowell]

Well, I ordered motor mounts and strut rod bushings; should know if they fixed the engine vibration and clunking sounds (two different problems) in a week or so. If it still clunks, strut mounts are my next project. I know they are the least probable cause, from all the comments I've seen, but my gut tells me different. I'll let you know. Thanks for the info.

Steve

where in Texas are you?

[Steve Chambers]

I just replaced the strut bushings on a 1998 LS400 (with Poly). I haven't driven much yet, but initial testing does show harsher ride over potholes, etc, and a harsher sound.

One thing I found during the replacement work though, was that the bolts holding the (old) bushings were somewhat looser than spec (121 lb-ft), especially on the right side. It's simple to re-torque these 22mm nuts (after removing the undercover) and I think these should be checked first. My most obvious symptom was a lot of creaking sound while turning sharply at low speed - primarily in parking lots. In retrospect, I think a simple tightening would have curtailed a lot of that creaking.

(I posted this on another Lexus site also)