Harsh riding '05 LX this can't be normal

[tom.]

Hi,
My problems are similar to Ivan80’s.
I have bought my car few months ago (50K, ‘02) and since then I try to resolve AHC suspension problem. The ride is harsh and it is only noticeable at slow speed on expansion joints/cracks, potholes. On highway speed and bigger road imperfections everything seems to be Ok.
I have changed accumulators, checked sensors, shocks pressure, set everything (t-bars, sensors, car height) to correct specifications, fitted new tires (pressure front 30, back 32), changed AHC fluid three times and suspension works like before. Maybe there is improvement in the difference between sport and comfort settings but it does not make any changes for road expansion joints/cracks at slow speed. I feel like suspension does not absorb this small road imperfections.
Does anyone have any ideas what can resolve this problem?
Thanks

 

[Jim_Chow]

Don't expect it to ride like a caddie sedan over small imperfections/cracks in the road. You will still feel those, regardless of what truck you drive in. The only way you wouldn't is if the vehicle had 4 wheel indep suspension with very soft springs/shocks. Anyways, you should notice a significant difference between comfort and sport if you drive slow with one side of the car going over a speed bump. Try it in both modes. In comfort, the bump should be a lot less noticeable while in sport, it'll be as if you had a stiff sport suspension.

 

[CivicFerio]

Car manufacturers have different taste when it comes to damper settings. My observation on Toyotas in general, is they have good high speed damping giving you more road feel. At the same time a moderate mid to low speed damping for better ride on dips and bumps, but gives floaty feel at higher speeds (80mph+).

My observation on the AHC system is that it stiffens up the mid-low speed damping the faster you go. It gives you the best of both worlds. Low speed comfort and high speed body control. Though I sometimes like feel it needs a tad less on the high speed damping to iron out the road imperfections.

I'm a big fan of KONI shocks and their damping philosophy. I wish Koni has made an FSD suspension on our land cruisers. Maybe I can talk to them at PRI next week.

Koni FSD info

Koni: FSD

 

[uHu]

I noticed there are bubbles in the reservoir top of the fluid. Is this normal? The fluid is dark brown.

The truck has 55K miles on it and no CPO warranty(see sig line) and the tires are at 30f, 28r (see first post).

I'm thinking the Dunlops are a lot of the problem. I'm going to replace the tires in the next month, they're borderline anyway. And I'll R&R the AHC fluid.

There is definitely something wrong with your fluid. The color might even be from dissolving membranes in the spheres, and seals in the shocks and actuator valves.
I recommend you not only replace the fluid, but take off the shocks and flush them too. Remember to bleed well, also at the (pressure)accumulator (at the middle of the DS frame rail). It's easier if you avoid getting air into the pump/reservoir while changing the fluid.
And - the sooner the better.

 

[tom.]

I have heard that LC with AHC suspension rides better than Mercedes S, and if it is truth, I would like my car to be like that. My previous Toyota sedan drove smoother in conditions which I have described previously. I tried test with a speed bump and there was a significant difference between sport and comfort. When tried with two wheels going over bump together, it was much more rough but I think this is normal for all cars. Sometimes want to give up, but I have spend to much money … I need to resolve this problem.

Did anyone heard about any problems with ECU TERMINAL? Is there something like Harshness controller which controls the damping force? If so, how can I check them?

Thanks

 

[SWUtah]

I have heard that LC with AHC suspension rides better than Mercedes S, and if it is truth, I would like my car to be like that.
Thanks

My SL rides alot better then my LX even over bumps. The SL's suspension is under 2700 lbs of pressure, very high tech and it works.

 

[scrappyslexus]

After numerous visits to the dealer they finally decided that the accumulators were shot. The dealership blamed it on AHC contamination which was bull because they did all the services. I pulled oil samples and the AHC fluid was fine. The accumulators just went. You may be able to get it repaired under warrenty. My truck was very bouncy, barely noticeable on a flat highway. I called 4 lexus dealers and took it to the one dealer that understood what I had them qouting on. i got it done for $2300. The job is simple but needs to be done correctly flushing system ,bleeding and draining shocks. Good luck.

 

[SWUtah]

After numerous visits to the dealer they finally decided that the accumulators were shot. The dealership blamed it on AHC contamination which was bull because they did all the services. I pulled oil samples and the AHC fluid was fine. The accumulators just went. You may be able to get it repaired under warrenty. My truck was very bouncy, barely noticeable on a flat highway. I called 4 lexus dealers and took it to the one dealer that understood what I had them qouting on. i got it done for $2300. The job is simple but needs to be done correctly flushing system ,bleeding and draining shocks. Good luck.

How many miles did you have on your LX when you think they went bad?

 

[CivicFerio]

I have heard that LC with AHC suspension rides better than Mercedes S, and if it is truth, I would like my car to be like that. My previous Toyota sedan drove smoother in conditions which I have described previously. I tried test with a speed bump and there was a significant difference between sport and comfort. When tried with two wheels going over bump together, it was much more rough but I think this is normal for all cars. Sometimes want to give up, but I have spend to much money … I need to resolve this problem.

Did anyone heard about any problems with ECU TERMINAL? Is there something like Harshness controller which controls the damping force? If so, how can I check them?

Thanks

I believe its just the nature of our vehicles to ride like that. Especially at higher speeds where unsprung weight plays a key role in handling dynamics. The heavier axles and wheels create the ride characteristics that we experience.

I think Toyota did a very good job tuning the suspension of the flagship 100 and 100 with AHC to the way it is. Compared to my 80 series, it's miles apart when it comes to NVH.

 

[tom.]

thank you for opinion

Has anyone tried Lexus GX470 with Adaptive Variable Suspension or Toyota equivalent?
If so, which one was softer and less harsh to drive?

Thanks

 

[SWUtah]

I'm starting to like to drive mine set clear over on "Sport". Very solid on the highway and not that bad on the back roads. I like the firm feeling.

 

[dfrelich]

I set mine at sport most of the time. I find that if I drive "comfort" in the back roads where roads are not so smooth and flat like interstate. The ride feel like I'm riding in the boat over smooth glass on calm day. You still feel some up and down motion. Even more noticeable in the dark where light shines up and down.

Dont get me wrong... it is not too bad. Just too much for my preference.

"Sport" is my choice. However, when riding on the interstate... comfort is very nice.

I'm starting to like to drive mine set clear over on "Sport". Very solid on the highway and not that bad on the back roads. I like the firm feeling.

 

[1loudLX]

I wish the sport was firm without the harshness, after riding in a bilstein equipped truck I cant but keep wishing for that ride compared to the AHC "sport" ride.

 

[scrappyslexus]

My LX had 50k when the rough ride developed, Dealer finally figured out it was accumulators after the warrenty ran out. In reference to the GX suspension. My new GX470 rides alot better then the 2000 LX.

 

[Dan Dibble]

Drove my wife's '05 LX today, and I cannot believe how harsh and rough it rides. The problem is most noticeable at slower speeds, and when you get to highway speed it's not too bad,

AHC set to comfort. Ride height works, comfort/sport setting seems to do nothing for the harshness, although it corners marginally flatter in sport.

Hi,
My problems are similar to Ivan80’s.
I have bought my car few months ago (50K, ‘02) and since then I try to resolve AHC suspension problem. The ride is harsh and it is only noticeable at slow speed on expansion joints/cracks, potholes. On highway speed and bigger road imperfections everything seems to be Ok.
I have changed accumulators, checked sensors, shocks pressure, set everything (t-bars, sensors, car height) to correct specifications, fitted new tires (pressure front 30, back 32), changed AHC fluid three times and suspension works like before. Maybe there is improvement in the difference between sport and comfort settings but it does not make any changes for road expansion joints/cracks at slow speed. I feel like suspension does not absorb this small road imperfections.
Does anyone have any ideas what can resolve this problem?
Thanks

Im experiencing the same condition.

Our 98 LX100 (225,000 miles) had the bouncing suspension no matter where the firmness was positioned. Found flat accumulators. replaced all four. this was about three years ago (50,000 miles ago)

It doesent bounce like it did with the flat accumulators. Just a harsh ride, more noticable at slow speeds no matter where the firmness control is. I checked the firmness control over a few speed bumps tonight and it is working properly. This is not the same condition as when the accumulators were flat.

The truck has always has the correct toyota fluid. And the Michilens have been on it for a few years with no problems.

Any new ideas on this problem?

Dan

 

[CrusrDug]

I am feeling the same thing on my 06 and 55k. I thought it was in my head since it's colder outside, but don't think so. Only at slower speeds. First thing I'm going to do is a fluid change since it's due at 60k. Then I'm going to adjust the TB's since they may not be as strong after 4 years.

 

[SWUtah]

I did my LX just a few months ago at 55K miles. Rides like new again. I think you just need to do the correct maintaince and no problem.

 

[Dan Dibble]

I did my LX just a few months ago at 55K miles. Rides like new again. I think you just need to do the correct maintaince and no problem.

You did what??

What "correct" maint?

The accumulators were changed and the fluid was flushed at that point and has been again last year.

I am feeling the same thing on my 06 and 55k. I thought it was in my head since it's colder outside, but don't think so. Only at slower speeds. First thing I'm going to do is a fluid change since it's due at 60k. Then I'm going to adjust the TB's since they may not be as strong after 4 years.

What are the "TB's"???


The problem is, you can feel every manhole cover or slight crack in the road as if the tires were way over inflated and the suspension was super firm.

Thanks, Dan

 

[RoderickGI]

TB = Torsion Bars

I just changed globes, flushed the system, and tightened the Torsion Bars up to near the maximum, from an initial setting near the minimum. I did this because I wanted to compensate for all the extra weight of the bull bar, winch, second battery etc. I have fitted to the front. I am using special order globes from B&B Suspension, which are actually set to lower pressures than standard, to give me more travel in the suspension while riding more on the springs than the AHC. That is, I am running the AHC at lower pressures, which means the pump doesn't have to work as hard, but I still get the full travel from the globes and normal damping.

Note that I had previously installed Old Man Emu (OME) 862 springs on the rear to support the extra weight of a long range tank, rear bumper and two wheel carrier, roller drawers, cargo barrier, radio, camping gear etc. in the back. This means that when I don't have a load in the back the truck is almost entirely running on the springs, rather than supported by the AHC. That screws up the ride a bit, so I try to run with full tanks and leave the roller draws in place, to get a better ride when I'm not carrying gear or two spare tyres.

Anyway, during the install process, before changing the globes I tightened up the Torsion Bars, and I found this improved the ride a great deal all by itself. I got less bounce at the rear, and better ride at the front. Basically supporting more weight on the Torsion Bars meant that the front globes, which weren't as flat as the rears, were less compressed, with less oil in them at the rest, which meant there was more capacity for the globes to absorb oil without filling the globes, and with more oil flow, more damped travel of the "shock absorbers". ( The bounce was fixed by the new globes.)

I still get a firmer ride that is a little harsher than it was when new, but that is not surprising given all the extra weight on the truck, and the heavy tyres I'm using.

So, try tightening the Torsion Bars to improve your ride.

 

[Ivan80]

I did my LX just a few months ago at 55K miles. Rides like new again. I think you just need to do the correct maintaince and no problem.

Let us know what it is you did exactly. Did you have the harsh ride prior to whatever it is you did?

As an update, I replaced the tires last spring with Michelins (it previously had Dunlops), ride only marginally improved, but that honeymoon is over.

Every imperfection and expansion joint in the road is felt as a jolt, however as I described previously (and as Dan also stated), it absorbs larger bumps like speed bumps fine.