WaveRunner

Didn't you install KYBs on your 1997?

I bought four KYB shocks. 2 front KYB strut mounts, 2 OEM rear strut mounts, and OEM spring bumpers and insulators. I haven't had them installed yet and not really in an immediate rush. My 1998 has 154k miles. It rides fine but the handling is sometimes suspect over 80MPH. Also it seems to have a little bounce on uneven surfaces. Body control when braking doesn't seem as it should and lack of confident planted feel. Then again I didn't own the car new so no idea how to compare it to how it was previously. These issues are not serious in terms of overall driveability but enough to make me assume the car needs new shocks.

400fanboy

I had my suspicions about how the car handled, but that wasn't enough on it's own. I replaced the ball joints and front shocks, mounts and insulators. But the primary motivation for me doing this was noise; there were clunks bangs at low speeds and driveways that appeared this winter during the first snow\ice. That really beat my car up and was the straw that broke the camels back I think. I think my ball joints and my shock mounts were the culprits. And if you're gonna replace the shock mounts, may as well do the whole assembly while you're in there since parts are a rounding error compared to labor costs.

400fanboy

Final update, figure I would share this for anyone who comes across this thread in the future. It took me about a month to get to the bottom of this because life became rather busy, I wanted to do the motor mounts first and isolate this problem, and my shop agreed to do the work for free if we scheduled it out a little further. Okay, not the end of the world. I can work with that.

As I alluded to above, I emailed KYB support, explained my issues. Their reply was the following:

And you know what, it ****ing worked. Pulling out of the parking lot I noticed a difference, and by the time I made it a block I knew this had solved it. The glide is back! The stiffness in the rebound at the front of the car is completely gone, it no longer feels like some super stiffly dampened sports car. It's kind of shocking the difference and I'm glad that I refused to accept that the car wasn't driving like it should. But I'm just glad the saga is over and finally, after 3 months of working since the winter storm & ice killed my front suspension, the rebuild is complete. Sway bar bushings, lower ball joints, the entire shock assembly, motor and transmission mounts. It's unbelievable how fresh it rides now. My shocks weren't broken, the mounts were though and making quite a bit of noise and had a lot of play. The biggest ride quality improvements came from lower ball joints and the motor\trans mounts.

For those of you who have had experiences in GT3 Porsches, Subaru WRX and specifically the Ford Focus RS; that is the level of stiffness in the dampers I was experiencing. Instead of "falling" into a bump like normal cars do, this level of stiffness actually pushes you "up" on smaller bumps causing some really nasty ride quality issues. The car would actually get pushed up from these small insignificant bumps, showing that the dampers actually weren't compressing at all until you hit them with a big enough load where they would compress.

Side note: does anyone know why this worked? I don't understand the geometry of why doing this process would soften up the ride. Was there an error in the install process of my shop that caused the shocks to become a load-bearing component? Is this a non-standard practice they had me do compared to most other normal cars? If I had to guess, it sounds like during the install when the suspension was hanging in the air, this applied a slight torque in the mount\top where the shock mounts to the body. And when the bolts were torqued down, this caused the geometry to be ever-so-slightly out of alignment. Enough to cause the shocks to become load bearing. Am I on the right track here?

CLLEXUSS

Well then it was sort of a pre-load problem! I was suspecting that, I remember I posted that a month ago in this thread. KYB basically believes the struts were locked out which seems to be the case. It's probably just an extreme geometrical position with succession of a series of geometrical angles that under certain circumstances can lock the struts sometimes if all components are tightened down with the vehicle in the air and the full weight of the suspension hanging down on the struts. Sure seems to be the case, congrats! It's fixed!

oldskewel

iTrader: (1)

Nice followup. Glad to see you stayed with it until it got fixed. Many would have bailed out, said how KYB sucks, and we'd never know the answer.

It sounds to me like basically the struts were locked in place by the 3 mounting nuts and the piston rod nut. If those are all tightened to final specs while the vehicle is in the air, there may be some deflection of the piston rod that is then locked into the system. So when you're back down on the ground, the piston rod is being forced to be slightly off center, which would cause binding. Every time you'd go up and down, that piston rod would actually need to bend. It would still move, but the binding force would be far greater than the damping force it is supposed to provide.

By lowering it on the ground, you set it at nominal ride geometry. Then with all 4 nuts loosened, and bouncing it, you allow it to find its center, where the piston rod is where it wants to be, without binding. Then you torque things down and it will always be centered there.

To me, this is the pretty obvious correct way to do it the first time. Similar to installing new bushings or other suspension components (or anything where being centered in its nominal geometry is important). So it's not really a special fix, just the way it should be done. And I bet KYB comes across it enough that they have that tech support answer ready to go.

So if you ask me, the shop made a mistake on the initial install. And they made another mistake by handing the car back to you with such an obvious problem. Nice that they finally did the re-do for free.

96DWPLS400

Thanks for the follow up. Now I can go back to looking at KYB shocks.

400fanboy

I too asked about long term damage, and this was their reply

So far I don't notice any issues. The car drives as I would expect now and I don't see any moisture much less any oil leaking onto the ground. So, so far, I think the shocks survived the initial break-in, 24 hours and about 50 miles of driving.

Thanks a ton for the writeup oldskewel. I now understand how the internals of a shock work a little bit better. I really do hope the shocks themselves don't have internal damage that will be a problem in the long term. I'm guessing if the piston rod was bending, this may cause some sort of seal failure on the top of the shock which would allow oil to escape? I guess we'll just have to see.

Onward and upward. Again a big thanks to everyone who helped with this problem.

Side note- KYB technical support is awesome. You just email them (with no account signup BS) and you get a reply the same-working day from a technical minded person (I've had several back and forths, they aren't copy+pasting a pre-defined document).

JohnAndic

I am very happy it worked out for you. Crazy how much you had to fight to get it right though. if it was up to your garage you'd be driving around with a ****ty ride until the struts did break. Then they would charge you to install another pair the same wrong way I bet. good luck going forward man!!

paulo57509

Damn. Talk about tenacity in getting this solved.

FWIW, I scanned through the front shock absorber pages of the FSM, buried in the disassembly steps is a "hint"...."At the time of installation, after stabilizing the suspension, torque the bolt." But this is in reference to the lower mounting bolt and not the nut at the top.

In my experience in doing suspension work, there are certain things (like control arm pivots with bushings) that aren't supposed to be tightened unless the weight of the car is on the ground.

deanshark

We had this discussion last year when "peterls" did his tutorial on "upper control arm install". At that time noone knew for a fact if the UCA bushing bolts needed to be preloaded. I read all through my 93 manual and the only thing that had to be preloaded was the lower shock bolts and a couple rear suspension bushings. (I can't remember which) Since then I finally changed my UCAs and can say for a fact that you DO NOT need to preload the UCA bushing bolts. I tightened mine to torque and they do pivot (as they're supposed to) up and down as far as you can move it. I meant to add this into that thread but it slipped my mind. Too much stress lately.
OP; glad to hear ya got your shocks straightened out.

oldskewel

iTrader: (1)

Yes, I remember that too. And I think the instructions that came with the parts in that case said to torque once lowered on the ground, which we concluded was not necessary. But this situation here is an example of why general principles like that are often given as advice / official instructions even when not strictly necessary. (so the Lexus manual said not to bother; the non-Lexus parts had instructions that said to torque after level) Can't hurt, might make a difference, so ...

High performance (like this) suspensions are usually designed trying to be close to linear - so things mostly move in a straight line as the wheel moves up and down, vs. deflecting off that straight line. If these Lexus suspensions were perfectly linear, it would not matter whether torqued in the air or on the ground. But since they're just pretty close to linear but not perfect, there is a slight deviation as the strut extends. So that's why you lock it in when it is in its nominal state, which is sitting on the ground.

Definitely the best way to do it. Whether or not it actually matters will depend on other factors.

400fanboy

Thanks a bunch everybody. It indeed was one hell of a saga. I'm just happy to be on the road with quiet, comfortable suspension which is exactly what I bought the car for. If the car wasn't comfortable and riding properly, the car wasn't accomplishing the goal that I own it for. You can get comfortable AND well handling suspension, but you have to spent a hell of a lot more money to accomplish that (usually by going German). So I'm maximizing comfort and ride quality over handling in every situation vs. putting poly bushings, stiffer swaybars and lowering coilovers on it. You're never going to make this car handle properly, but you can make it ride properly. And it is phenomenal how good it gets.

I'm just happy to have finally reached there after being beaten down by that first winter storm which broke basically everything. I have a feeling that after 22 years, the car was on it's "last legs", and all it took was a good knocking from a ton of ice to be the final straw that breaks the camels back. I only wish I didn't have to replace everything but the control arms on my front suspension to get there lol. Total cost including labor for everything was about $2700, with a roughly 50\50 split between parts and labor. KYB shocks were the only non-OEM part that I put on. I live in an area with ~$110\hr labor rates, so it's not the cheapest out there compared to rural areas where you're down in the $80's. I'm just glad I didn't have to pay the $180 dealership labor rates. I'm also not a wrench, with neither the tools nor the facilities to do my own oil changes - much less replacing suspension components.

But thanks to enough information on these forums, I was able to correctly diagnose every single problem on the front suspension one-by-one. Every single part I replaced fixed something, either a handling characteristic or a noise. Rusty door hinge? Sway bar bushings. Judder and clunking noises going over bumps? Shock mounts. Sensitivity to road camber and excessive body roll AND clunking noises? Lower ball joints. Vibration at idle, loss of the "glide" and harsher gearshifts? Motor\trans mounts. And in the process I've learned a wealth of information, especially on the diagnostic side.

If you're curious on my car, here is an album of pictures I've assembled throughout my ownership. It's the perfect spec (silver on black) in AMAZING condition, so I'm a lot more willing to invest in it and keep it fresh for whoever will own it after me than if it had ripped leather, a salvage title and twice as many miles:

https://imgur.com/a/7HG0U

john341

Thank you for posting the solution. One of our car's Struts was recently replaced with KYB and was was very harsh afterwards. Yesterday morning i decided to follow the solution posted. All i can say is WOW! what a difference it made. I was planning to put some miles to break in the struts, before taking it back to the mechanic. saved me lot of time and headache.. Thank you.

400fanboy

I'm glad it helped, and your searches with the keywords led you to this thread. I try to keep things well documented for this exact reason.

It's really difficult when doing research to find someone who fixed the problem with "yeah I put it in the air, did some magic mumbo jumbo and it solved the problem!" or just "nvm fixed it".