front suspension fixes and facts
04-14-11, 09:29 AM
#197
Suspension Conjecture...
Anyone ever noticed that all of the suspension components of the GS430 are the same as an SC430? Except, ironically, for the lower control arm no. 2 (a.k.a., caster arm, tension rod). I do not see vibration issues discussed as frequently, relatively not at all, over in the SC430 forums (thus, models 2002 and up). I attribute that to possibly a lower volume produced car, newer model years, and, generally speaking, a car that is driven fewer miles. In other words, I think their time is coming.
I have a 2002 SC430, about 110k miles, and the shakes have started, along with the inside wear. Car is/has been aligned to the best of local's abilities. I plan to replace the caster arm first, now, before I do anything else.
However, I ALSO have a 1999 GS400, about 185k miles. I ended up changing the bushings to daizen (polyurethane with shoulders) about 20k miles ago (and ball joints and tie rods) based on weird tire wear, not any sort of shake. I also have 18" 2007 Lexus GS430 type wheels installed, and have been lowered by 1" with NF210 springs, and pushed out about ¾” all around with H&R spacers, for about 80k miles. I have a slight vibration right now, with a squirrly steering wheel response, which I think might be balancing and/or alignment. I think alignment is pretty darn close. Tires are relatively new and wearing fine thus far, but I need to mark them off the list by confirming balance and alignment.
MY QUESTION:
Has anyone ever 'upgraded' their 98-03 Lower Control Arms #2 to the 03-05 version in response to vibrations, and not done anything else? What were the results?
Here's why I ask: On the GS400, all of the daizen front p/u bushings are not just a different material, they are also shaped differently. They reinforce all of the shoulders of the 3 parts (UCA, LCA #1, LCA #2). They change the "degrees of freedom" for the whole set up. I can't help but wonder if I have created one problem by addressing another problem.
If you happen to be blessed with perfectly balanced wheel/tire combinations, then most of this discussion is probably moot. You probably have not even come across this thread yet. You either changed your bushings to OEM and never looked back because all was well, or you changed to daizen bushings (or equivalent) and never looked back because all was well. Either way, if you have nothing causing vibration (tire/wheel/road combo), then you have no concerns with all of the components that would transmit those vibrations (suspension arms, bushings, steering rack, et al.).
However, what about those that do not have those perfect tire/wheel balance combos? Are we doomed? Must we insist on going to high quality tire shops hours away, and being in their back pockets to insist that road force balance results in no more than 2 pounds force, where the industry standard might be 20?! And, need we fear some sort of tire anomaly developing in 10k miles? Only to recreate the tire shop episode all over again?
I have seen some of the "fixes" ascribed to extremely high quality wheel balancing. Problem is: that is not very practical. It should not be this hard. It should not need this much care. These cars are not so sensitive as to require such scrutiny. I am going to assume, for just a minute, that Lexus engineers are a tad more talented. Let’s assume they took standard tire manufacturing and standard wheel balancing into account. If anything, tires and balancing have drastically improved in the last 14 years since these vehicles were designed. Let’s remember guys, the 1998 GS400 was the fastest 4 door automatic in the world at the time. It was cutting edge. These cars were designed to cruise at 135mph comfortably, quietly, and smoothly. (I need a moment--I have goose bumps.)
I do not think perfect wheel balancing is the answer. I agree that it is a fix, but it is not the answer. I am also starting to doubt my wisdom in installing daizen (or ‘equivalent’) bushings. I fell that worn out OEM bushings cause vibration because the wheels are allowed to move around too much and cause alignment problems et al. However, I am also beginning to think that daizen bushings stiffen everything up too much, also resulting in transmitted vibration.
Let me discuss it all this way. Between the road and the steering wheel, there are 3 main spring variables: #1 spring: tires, #2 spring: bushings, and #3 spring: steering rack pre-tension adjustment and/or its bushings. IF OEM is 17” wheels, ‘soft’ bushings without shoulders, and ‘loose’ steering rack, then the ability to mitigate road forced vibrations to your hand is more easily achieved.
As we all do, let’s start changing variables. We stiffen spring #1: 18” wheels, or larger. These stiffer tires transmit more force to the bushings (and the LCA #2 will take it the most). Same vibration frequency, more force, quicker fatigue of the bushings, failure, alignment goes, etc etc. You replace the bushings OEM, all is probably well until the bushings fatigue again, who knows how quickly.
But let’s say you decide to change another variable. You keep the 18”+ wheels, you think your bushings are shot, so you replace with daizen bushings, thus stiffening spring #2. You post it on the forum, everyone cheers and expects similar results. For you, your wheel balance is already ‘better’, so your stiffened suspension does not result any issues for you. If you would have replaced with OEM, you would have had the same results (except less stiff suspension). However, for some, they will still have vibrations, because their wheel balance, although okay, might only be a 7/10 whereas yours is an 8/10. So, their bushings transmit too much, especially because their spring #2 is now stiffer.
Stiffer spring #1, stiffer spring #2…let’s stiffen spring #3. Tighten the steering rack (with the big bolt or the bushings or both). Same scenario as spring #2: for some, the increased stiffness of the entire system mitigates the vibrations, for others it does not.
Thus, my only point to make: realize increased stiffening of your suspension system may not be the answer. And, it might actually magnify other problems that you do not currently have, nor have others experienced.
All of the above rant is essentially to say that I agree MOSTLY with POST Numero Uno:
However, my suggestion is simply replace the LCA#2 caster arm with upgraded OEM components (i.e., 2003+ LCA #2, part no.486x0-30281). Although polyurethane bushings will result in success for maybe 80% of the viewing audience, I think the stiffer components will still cause the remaining 20% some problems over the life of the bushing (as tires wear), especially if you have lowered your vehicle and changed the angle of the caster arm with the bushing. However, I think the softer OEM will mitigate vibrations better, take the lowered angle better (because no shoulder) allow you to get normal quality tires balanced at normal quality shops, and give you another 75k-100k care-free miles.
IMO.
I have a 2002 SC430, about 110k miles, and the shakes have started, along with the inside wear. Car is/has been aligned to the best of local's abilities. I plan to replace the caster arm first, now, before I do anything else.
However, I ALSO have a 1999 GS400, about 185k miles. I ended up changing the bushings to daizen (polyurethane with shoulders) about 20k miles ago (and ball joints and tie rods) based on weird tire wear, not any sort of shake. I also have 18" 2007 Lexus GS430 type wheels installed, and have been lowered by 1" with NF210 springs, and pushed out about ¾” all around with H&R spacers, for about 80k miles. I have a slight vibration right now, with a squirrly steering wheel response, which I think might be balancing and/or alignment. I think alignment is pretty darn close. Tires are relatively new and wearing fine thus far, but I need to mark them off the list by confirming balance and alignment.
MY QUESTION:
Has anyone ever 'upgraded' their 98-03 Lower Control Arms #2 to the 03-05 version in response to vibrations, and not done anything else? What were the results?
Here's why I ask: On the GS400, all of the daizen front p/u bushings are not just a different material, they are also shaped differently. They reinforce all of the shoulders of the 3 parts (UCA, LCA #1, LCA #2). They change the "degrees of freedom" for the whole set up. I can't help but wonder if I have created one problem by addressing another problem.
If you happen to be blessed with perfectly balanced wheel/tire combinations, then most of this discussion is probably moot. You probably have not even come across this thread yet. You either changed your bushings to OEM and never looked back because all was well, or you changed to daizen bushings (or equivalent) and never looked back because all was well. Either way, if you have nothing causing vibration (tire/wheel/road combo), then you have no concerns with all of the components that would transmit those vibrations (suspension arms, bushings, steering rack, et al.).
However, what about those that do not have those perfect tire/wheel balance combos? Are we doomed? Must we insist on going to high quality tire shops hours away, and being in their back pockets to insist that road force balance results in no more than 2 pounds force, where the industry standard might be 20?! And, need we fear some sort of tire anomaly developing in 10k miles? Only to recreate the tire shop episode all over again?
I have seen some of the "fixes" ascribed to extremely high quality wheel balancing. Problem is: that is not very practical. It should not be this hard. It should not need this much care. These cars are not so sensitive as to require such scrutiny. I am going to assume, for just a minute, that Lexus engineers are a tad more talented. Let’s assume they took standard tire manufacturing and standard wheel balancing into account. If anything, tires and balancing have drastically improved in the last 14 years since these vehicles were designed. Let’s remember guys, the 1998 GS400 was the fastest 4 door automatic in the world at the time. It was cutting edge. These cars were designed to cruise at 135mph comfortably, quietly, and smoothly. (I need a moment--I have goose bumps.)
I do not think perfect wheel balancing is the answer. I agree that it is a fix, but it is not the answer. I am also starting to doubt my wisdom in installing daizen (or ‘equivalent’) bushings. I fell that worn out OEM bushings cause vibration because the wheels are allowed to move around too much and cause alignment problems et al. However, I am also beginning to think that daizen bushings stiffen everything up too much, also resulting in transmitted vibration.
Let me discuss it all this way. Between the road and the steering wheel, there are 3 main spring variables: #1 spring: tires, #2 spring: bushings, and #3 spring: steering rack pre-tension adjustment and/or its bushings. IF OEM is 17” wheels, ‘soft’ bushings without shoulders, and ‘loose’ steering rack, then the ability to mitigate road forced vibrations to your hand is more easily achieved.
As we all do, let’s start changing variables. We stiffen spring #1: 18” wheels, or larger. These stiffer tires transmit more force to the bushings (and the LCA #2 will take it the most). Same vibration frequency, more force, quicker fatigue of the bushings, failure, alignment goes, etc etc. You replace the bushings OEM, all is probably well until the bushings fatigue again, who knows how quickly.
But let’s say you decide to change another variable. You keep the 18”+ wheels, you think your bushings are shot, so you replace with daizen bushings, thus stiffening spring #2. You post it on the forum, everyone cheers and expects similar results. For you, your wheel balance is already ‘better’, so your stiffened suspension does not result any issues for you. If you would have replaced with OEM, you would have had the same results (except less stiff suspension). However, for some, they will still have vibrations, because their wheel balance, although okay, might only be a 7/10 whereas yours is an 8/10. So, their bushings transmit too much, especially because their spring #2 is now stiffer.
Stiffer spring #1, stiffer spring #2…let’s stiffen spring #3. Tighten the steering rack (with the big bolt or the bushings or both). Same scenario as spring #2: for some, the increased stiffness of the entire system mitigates the vibrations, for others it does not.
Thus, my only point to make: realize increased stiffening of your suspension system may not be the answer. And, it might actually magnify other problems that you do not currently have, nor have others experienced.
All of the above rant is essentially to say that I agree MOSTLY with POST Numero Uno:
Fixes
It really starts with 1 as it is the problem that kills all the rest of components.
It is the front caster arm bushings.
When they die your alignment goes to **** .
The front wheels toe out and the caster goes negative . Causing all of the problems above from one part.
You can replace them with oem's rubber bushings but the suspension geometry is not the best for them and multiplies the pressure. This causes them to fail under hard braking fast as it does not take much. Replace these with urethane and you will be able to go hopefully forever without a repair again.
It really starts with 1 as it is the problem that kills all the rest of components.
It is the front caster arm bushings.
When they die your alignment goes to **** .
The front wheels toe out and the caster goes negative . Causing all of the problems above from one part.
You can replace them with oem's rubber bushings but the suspension geometry is not the best for them and multiplies the pressure. This causes them to fail under hard braking fast as it does not take much. Replace these with urethane and you will be able to go hopefully forever without a repair again.
IMO.
04-14-11, 10:22 AM
#198
I must rant too. I have NEVER, EVER had so many front end problems with a rear wheel drive car as my Lexus GS300. Lets face it, this suspension design is flawed, plain and simple. There is no denying it. Resistance is futile. It wouldn't be the end of the world to me if you could just replace all the rubber bushings. But no, you have to change out every single control arm! Thats very, very expensive guys. If it wasn't we all would have done it already. No polyurethane for me by the way (except for one part maybe). This car is a luxury cruiser for me. I do not want to feel every nook and cranny on the road or hear it for that matter (can I get a squeak?).
Right now my car is OK. I have changed the Castor arms, lower ball joints, inner and outer tie rod ends (more than once) and aligned. I got the car so it will not eat a set of front end tires. I still have some vibration at high speeds, but I will stomach it for now. It will be OK until I hit my next pot hole...
OK, ranting is over. This all leads me to ask: what is unique to our front suspensions? The castor arms. It looks like a real bad design to me. That piece is just asking for abuse, deflection and whole suspension movement the way it is set up.
Degma, I hope the 03-05 is an improved design, because it is past due. You might be on to something.
Gears
Right now my car is OK. I have changed the Castor arms, lower ball joints, inner and outer tie rod ends (more than once) and aligned. I got the car so it will not eat a set of front end tires. I still have some vibration at high speeds, but I will stomach it for now. It will be OK until I hit my next pot hole...
OK, ranting is over. This all leads me to ask: what is unique to our front suspensions? The castor arms. It looks like a real bad design to me. That piece is just asking for abuse, deflection and whole suspension movement the way it is set up.
Degma, I hope the 03-05 is an improved design, because it is past due. You might be on to something.
Gears
04-14-11, 11:51 AM
#199
Gears12,
Actually, my rant was pointed more toward us, myself included. I do not think the design is bad, nor do I think the fix is to change all the control arms or ball joints or bushings. I think the ultimate fix is replace/repair the caster arm (LCA #2), and THAT IS ALL. About $280 in parts, 4 bolts, 2 nuts. For me, that is not that bad to do every 75k miles or more on a modified car.
I think most of the prior discussion over the YEARS is based on incorrect diagnosis, short-term fixes that lead to more problems later (i.e., stiffening the suspension system). As a result, we have painted a picture that essentially indicates the whole front end of these cars need to be replaced with non-OEM "upgrades" to address a bad design, and then some will STILL have vibration issues. I think that is just plain inaccurate. If we could take the time and be real scientific about it, we'd probably discover most have lowered their vehicle, increased wheel size, added spacers, and/or replaced bushings with non-OEM. Can't really blame Lexus for that, can we?
If you are purely OEM, and basic alignment is good and basic wheel balancing and tire quality is good, I'd bet a replacement of caster arm LCA #2 with OEM parts will last several years and several several thousand miles, vibration-free.
If you are not OEM, I still think a replacement with OEM parts is the way to go, but you MIGHT fail the ONE (each side) and only LCA#2 bushing sooner due to an induced steady-state deflection of the bushing upward from the lowering effects. That is also why I feel daizen might be bad for lowered cars. The stiff bushing, also with its large shoulders, resists the movement of the arm upward.
The GS3 design puts the caster bushing in the vertical plane, whereas GS2 is in the horizontal plane. I think the vertical plane offers advantages because bumps are not transmitted thru the caster bushings---it is all thru the spring/damper. A horizontal caster bushing takes all of the bumps...but the arms are so long that the deflections and forces should be minor.
And, as a final insult to this whole issue, I have found that lower tire pressure (I have 245s vs the OEM 235s) and LOOSENING the steering rack "bolt" mitigates my vibration. I have not seen that posted much...
Actually, my rant was pointed more toward us, myself included. I do not think the design is bad, nor do I think the fix is to change all the control arms or ball joints or bushings. I think the ultimate fix is replace/repair the caster arm (LCA #2), and THAT IS ALL. About $280 in parts, 4 bolts, 2 nuts. For me, that is not that bad to do every 75k miles or more on a modified car.
I think most of the prior discussion over the YEARS is based on incorrect diagnosis, short-term fixes that lead to more problems later (i.e., stiffening the suspension system). As a result, we have painted a picture that essentially indicates the whole front end of these cars need to be replaced with non-OEM "upgrades" to address a bad design, and then some will STILL have vibration issues. I think that is just plain inaccurate. If we could take the time and be real scientific about it, we'd probably discover most have lowered their vehicle, increased wheel size, added spacers, and/or replaced bushings with non-OEM. Can't really blame Lexus for that, can we?
If you are purely OEM, and basic alignment is good and basic wheel balancing and tire quality is good, I'd bet a replacement of caster arm LCA #2 with OEM parts will last several years and several several thousand miles, vibration-free.
If you are not OEM, I still think a replacement with OEM parts is the way to go, but you MIGHT fail the ONE (each side) and only LCA#2 bushing sooner due to an induced steady-state deflection of the bushing upward from the lowering effects. That is also why I feel daizen might be bad for lowered cars. The stiff bushing, also with its large shoulders, resists the movement of the arm upward.
The GS3 design puts the caster bushing in the vertical plane, whereas GS2 is in the horizontal plane. I think the vertical plane offers advantages because bumps are not transmitted thru the caster bushings---it is all thru the spring/damper. A horizontal caster bushing takes all of the bumps...but the arms are so long that the deflections and forces should be minor.
And, as a final insult to this whole issue, I have found that lower tire pressure (I have 245s vs the OEM 235s) and LOOSENING the steering rack "bolt" mitigates my vibration. I have not seen that posted much...
04-14-11, 01:01 PM
#200
and also, heres my thread about changing out the 98-00 arms to 03-05 arms.
04-14-11, 01:09 PM
#201
Degmla,
I guess we have different standards for cars. I have never had to change a bushing at 75,000 miles, foreign or domestic brand. Nor do I want to change it out every 75k and get an alignment every time. By changing to a newer castor arm to correct a problem proves there is a design flaw. If you are right about this newer castor arm, then Lexus knows there's a problem too (design change). My car is NOT lowered, or modified in any way. This car is not my high performance vehicle (I have two other cars way better suited for that). It is driven primarily on the highway. People have been posting and posting about vibration problems on these cars. You cannot ignore that. Not all of them are modified (maybe 50%). I am convinced this car has a weak front end design. Should I bring up the ball joint issues these cars have too? There's a sticky about that. This is not what I expect from a $50,000 car and a "Flagship" brand.
I am not here to Lexus bash. I just want to be clear that this not normal for other cars.
I hope you are right about the improved design castor arm.
Gears
I guess we have different standards for cars. I have never had to change a bushing at 75,000 miles, foreign or domestic brand. Nor do I want to change it out every 75k and get an alignment every time. By changing to a newer castor arm to correct a problem proves there is a design flaw. If you are right about this newer castor arm, then Lexus knows there's a problem too (design change). My car is NOT lowered, or modified in any way. This car is not my high performance vehicle (I have two other cars way better suited for that). It is driven primarily on the highway. People have been posting and posting about vibration problems on these cars. You cannot ignore that. Not all of them are modified (maybe 50%). I am convinced this car has a weak front end design. Should I bring up the ball joint issues these cars have too? There's a sticky about that. This is not what I expect from a $50,000 car and a "Flagship" brand.
I am not here to Lexus bash. I just want to be clear that this not normal for other cars.
I hope you are right about the improved design castor arm.
Gears
Last edited by Gears12; 04-14-11 at 01:15 PM.
04-14-11, 03:43 PM
#202
Gears,
I took this to mean that you had possibly changed your caster bushing to p/u (since there is no other bushing in your list). However, since you are completely OEM, then that is the type of feedback I am looking for. Are you 16" wheels or 17" wheels? I am hoping 17".
I do not feel an improved part necessarily demonstrates a design flaw, but more realistically a design improvement, thus demonstrating a design weakness in the original component. People have been posting and posting about vibration and I have been reading and reading. And, what I noticed is that most people SEEMINGLY chased wheel balancing and tie rods and ball joints and steering racks. Then some began to clear some of that up by drawing more attention to the caster arm as primary culprit, and now I am drawing attention to p/u POSSIBLY not being the best installation for the caster bushing because of added stiffness.
As for standards, my 75k was based on a MODIFIED vehicle, bigger wheels, wider tires, lower springs, widened wheel base. But, OEM, I think 75k is low...I'd expect more. If you are pure OEM, and are having unresolved vibration or recurring vibration, I'd be upset.
**********
Coco-bun,
Read your thread(s) in the past...several times. It is part of my inspiration. Many thanks to you for your prior research.
No polyurethane for me by the way (except for one part maybe). Right now my car is OK. I have changed the Castor arms, lower ball joints, inner and outer tie rod ends (more than once) and aligned. I got the car so it will not eat a set of front end tires. I still have some vibration at high speeds, but I will stomach it for now.
I do not feel an improved part necessarily demonstrates a design flaw, but more realistically a design improvement, thus demonstrating a design weakness in the original component. People have been posting and posting about vibration and I have been reading and reading. And, what I noticed is that most people SEEMINGLY chased wheel balancing and tie rods and ball joints and steering racks. Then some began to clear some of that up by drawing more attention to the caster arm as primary culprit, and now I am drawing attention to p/u POSSIBLY not being the best installation for the caster bushing because of added stiffness.
As for standards, my 75k was based on a MODIFIED vehicle, bigger wheels, wider tires, lower springs, widened wheel base. But, OEM, I think 75k is low...I'd expect more. If you are pure OEM, and are having unresolved vibration or recurring vibration, I'd be upset.
**********
Coco-bun,
Read your thread(s) in the past...several times. It is part of my inspiration. Many thanks to you for your prior research.
04-15-11, 09:16 AM
#203
I am completely OEM. I have 16" factory chrome Lexus wheels with 215/60/16 tires. My replacement Castor arms are straight from Carson Toyota. My reference to the polyurethane: I am thinking about using some poly rack bushings.
My car was seriously eating tires before I changed the Castor arms. These arms are tough to troubleshoot using existing methods. They didn't exhibit much too much play having the car jacked up. I finally noticed it when the suspension was in a certain position, I saw that the bushing was pretty cracked. After changing the arms it probably reduced the vibration by about 60%. This was done about two years ago. Keep in mind I had several professionals troubleshoot the front end. No one could ever find anything wrong. The biggest improvement with the arms was the reduction in tire wear.
As far as wear on the other suspension parts, they were all legit. All were verified having excessive play, before changing, by me. These parts are pretty easy to troubleshoot.
My reference to changing out all the rubber bushings on an earlier post means this: Normally, if I was having this much trouble with front end vibrations and tire wear, then I would rebuild the entire front suspension. If you could change out each bushing individually then this wouldn't be unreasonable. You might even be able to get a kit for further cost savings (maybe $160). This way, when you are done, you will have a factory fresh front end and everything like new. But since you cannot change each bushing and have to buy EVERY arm, FROM Lexus this is out of my price range. I think I looked into it and it was like $1300 just in arms, at internet prices (discount).
If you look at how the lower suspension is designed, it is just asking for problems. First having a two piece lower control arm is not the ideal way to have strength in your suspension. The lower control arm takes most of the abuse and movement is not ideal. Second, the castor arm is what is really keeping that first arm straight and true. However, the back end of the castor arm has a bushing that will allow it to move in ANY direction. To add to this, this particular bushing is not uniform in construction (thin in some spots). Lets add even more to this: bushing wear and play. Now you have your whole lower control arm moving around! I am sure this is doing just wonders for tire alignment and handling, especially under a heavy load (like braking)! If you can just picture the lower control arm moving around: Can you see why there are so many vibration issues at speed? Heavy tire wear due to deflection and misalignment? Premature suspension wear (worn lower ball joints, tie rod ends) due to excessive movement and oscillation?
I do like the SLA design suspension, but in my opinion they messed up on the lower control arms. If they would have used traditional style, true "A" style, forged aluminum lower arms, (like the upper arms) I dont think this stickied thread "Suspension Fixes" would even exist.
I hope this helps,
Gears
My car was seriously eating tires before I changed the Castor arms. These arms are tough to troubleshoot using existing methods. They didn't exhibit much too much play having the car jacked up. I finally noticed it when the suspension was in a certain position, I saw that the bushing was pretty cracked. After changing the arms it probably reduced the vibration by about 60%. This was done about two years ago. Keep in mind I had several professionals troubleshoot the front end. No one could ever find anything wrong. The biggest improvement with the arms was the reduction in tire wear.
As far as wear on the other suspension parts, they were all legit. All were verified having excessive play, before changing, by me. These parts are pretty easy to troubleshoot.
My reference to changing out all the rubber bushings on an earlier post means this: Normally, if I was having this much trouble with front end vibrations and tire wear, then I would rebuild the entire front suspension. If you could change out each bushing individually then this wouldn't be unreasonable. You might even be able to get a kit for further cost savings (maybe $160). This way, when you are done, you will have a factory fresh front end and everything like new. But since you cannot change each bushing and have to buy EVERY arm, FROM Lexus this is out of my price range. I think I looked into it and it was like $1300 just in arms, at internet prices (discount).
If you look at how the lower suspension is designed, it is just asking for problems. First having a two piece lower control arm is not the ideal way to have strength in your suspension. The lower control arm takes most of the abuse and movement is not ideal. Second, the castor arm is what is really keeping that first arm straight and true. However, the back end of the castor arm has a bushing that will allow it to move in ANY direction. To add to this, this particular bushing is not uniform in construction (thin in some spots). Lets add even more to this: bushing wear and play. Now you have your whole lower control arm moving around! I am sure this is doing just wonders for tire alignment and handling, especially under a heavy load (like braking)! If you can just picture the lower control arm moving around: Can you see why there are so many vibration issues at speed? Heavy tire wear due to deflection and misalignment? Premature suspension wear (worn lower ball joints, tie rod ends) due to excessive movement and oscillation?
I do like the SLA design suspension, but in my opinion they messed up on the lower control arms. If they would have used traditional style, true "A" style, forged aluminum lower arms, (like the upper arms) I dont think this stickied thread "Suspension Fixes" would even exist.
I hope this helps,
Gears
Last edited by Gears12; 04-15-11 at 09:57 AM.
04-19-11, 05:34 AM
#204
Gears,
Sorry about all of your problems. I do not agree with all of your suspension design comments, but I agree that what you have described in regard to your own experience is onerous.
Some good news: I just purchased 2 lower control arms #1 and 2 of the "upgraded" lower control arms #2 for my 1999 GS400 for just shy of $375, delivered. LCA#1 are not OEM, LCA#2 is OEM. I will try and keep everyone updated over the next several months.
Yesterday, I was looking for a place locally that would do "road force balancing". As a result of that search, I stumbled across something interesting: other types of cars are also seemingly experiencing the 55-65mph vibrations. The 2 forums I recall were Acura TL and Corvette. Those particular threads were attributing their issues to poor wheel/tire balancing.
For now, my personal contention is this: stiffening the suspension system has probably caused me more vibration issues than keeping OEM. Initially, I should have replaced the caster arms (LCA #2) with the newer OEMs, and been done. I am now going back to OEM, and I intend to update with my experiences.
Sorry about all of your problems. I do not agree with all of your suspension design comments, but I agree that what you have described in regard to your own experience is onerous.
Some good news: I just purchased 2 lower control arms #1 and 2 of the "upgraded" lower control arms #2 for my 1999 GS400 for just shy of $375, delivered. LCA#1 are not OEM, LCA#2 is OEM. I will try and keep everyone updated over the next several months.
Yesterday, I was looking for a place locally that would do "road force balancing". As a result of that search, I stumbled across something interesting: other types of cars are also seemingly experiencing the 55-65mph vibrations. The 2 forums I recall were Acura TL and Corvette. Those particular threads were attributing their issues to poor wheel/tire balancing.
For now, my personal contention is this: stiffening the suspension system has probably caused me more vibration issues than keeping OEM. Initially, I should have replaced the caster arms (LCA #2) with the newer OEMs, and been done. I am now going back to OEM, and I intend to update with my experiences.
05-11-11, 03:18 PM
#205
So, I finished replacing the Lower Control Arm #2 and the LCA#1 this weekend with OEM (or aftermarket "equivalent"). Wanted to remove all of the daizen bushings. The SBC Upper Control Arm is relatively new, as is the lower ball joints and outer tie rods...so those were not changed.
I initially home aligned the suspension (I can usually do as well as their fancy machines), but I realize that is still a variable. However, I have gotten pretty good at camber, and toe is measured within 1/16" and then confimed with the instant gas mileage flash during a 70mph cruise. So, for now, I assuming it is "good enough".
I also had my relatively new tires (4k miles) road force/match balanced by a 2nd separate tire place.
CONCLUSION: shakes are still there! However, they are different, so I am still resolved. And, so far, less than $400 spent (and a day with the wrenches). I also did new brakes and rotors...so not a total waste of time.
Next item: INNER TIE RODS. PO'ed I did not think of this before...steering rack and pre-tensioner and outer tie rods all on the mind, but never the inners. I am thinking mine are bad, based on other posts I have read. I am thinking mine tend to fall when you let go of them...will head home to check, and then place a pair on order.
Also condsidering MOTOR MOUNTS. After 185k miles, it might be time?
I also played around with pre-tensioner and tire air pressures...no real change that I noticed. Will keep you all updated...hopefully with a success story.
I initially home aligned the suspension (I can usually do as well as their fancy machines), but I realize that is still a variable. However, I have gotten pretty good at camber, and toe is measured within 1/16" and then confimed with the instant gas mileage flash during a 70mph cruise. So, for now, I assuming it is "good enough".
I also had my relatively new tires (4k miles) road force/match balanced by a 2nd separate tire place.
CONCLUSION: shakes are still there! However, they are different, so I am still resolved. And, so far, less than $400 spent (and a day with the wrenches). I also did new brakes and rotors...so not a total waste of time.
Next item: INNER TIE RODS. PO'ed I did not think of this before...steering rack and pre-tensioner and outer tie rods all on the mind, but never the inners. I am thinking mine are bad, based on other posts I have read. I am thinking mine tend to fall when you let go of them...will head home to check, and then place a pair on order.
Also condsidering MOTOR MOUNTS. After 185k miles, it might be time?
I also played around with pre-tensioner and tire air pressures...no real change that I noticed. Will keep you all updated...hopefully with a success story.
05-12-11, 07:27 AM
#207
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DEFINITELY time for motor mounts, and probably tranny mount as well.
My memory of the thread is a bit vague. Have you also changed out your lower ball joints recently? If not, I'd add that to your list.
Let us know what you find out.
My memory of the thread is a bit vague. Have you also changed out your lower ball joints recently? If not, I'd add that to your list.
Let us know what you find out.
05-12-11, 12:47 PM
#208
My memory of the thread is a bit vague. Have you also changed out your lower ball joints recently? If not, I'd add that to your list.
However, i do confess...I thought I got them tight, until I came across the suspension specs the next day and realized those puppies are torqued to 120 ft-lbs!!!! Oops...luckily, I had only driven about 30 miles on them. They were easy to re-torque...turn steering wheel, remove cotter pin, and start torquing. I was quite surprised and embarassed about how much more turning I got out of it. I was probably about 80 ft-lbs initially.
05-12-11, 01:44 PM
#209
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What about your strut top perches? Have you replaced those? Replacing those will help. To what degree I don't know. I had mine replaced with some other suspension parts(arms, struts, etc). My mechanic told me I needed to have mine replaced as well.
All better now, but I don't know how much of the improvement was due to the perches. I don't know what the actual name for them are, but that's just what my mechanic referred to them as.
All better now, but I don't know how much of the improvement was due to the perches. I don't know what the actual name for them are, but that's just what my mechanic referred to them as.
05-31-11, 02:33 PM
#210
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I had my lower ball joints replaced and also swapped out the old caster arms for the newer (03-05) design. Got the wheels balanced and went to get an alignment this morning. Now, when I took the car in this morning, the steering wheel was cocked slightly left of center, maybe about 5-7 degrees.
Now, the wheels are "properly aligned," but the steering wheel sits 45 degrees right of center!? The mechanic asked me if the car has ever been in a wreck in which I replied "no"
He advised that I take the car back to where I had the LBJs and caster arms replaced and have them take a look at it. I drove the car home and it feels MUCH better, other than the fact that the steering wheel is 45 degrees right of center. Any suggestions???
Now, the wheels are "properly aligned," but the steering wheel sits 45 degrees right of center!? The mechanic asked me if the car has ever been in a wreck in which I replied "no"
He advised that I take the car back to where I had the LBJs and caster arms replaced and have them take a look at it. I drove the car home and it feels MUCH better, other than the fact that the steering wheel is 45 degrees right of center. Any suggestions???