I wonder if it could be body mount bushings? I actually have those already, but it seems like a lot of work, hahaha.
AHC with harsh ride (1 Viewer)
- Thread starter kgrove
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uHu
Bridgeburner
I've seen, here on mud, a few cases like this reported. Really puzzling.
When everything measures the same as on a truck with a more comfy drive, what can be wrong?
One thing to check, if you haven't, is that the steering sensor is straight, as the L/R valves (gate) will close at a steering angle of more than 30 deg (or was it 35), which gives a harsher ride (like having a solid anti roll bar).
Otherwise, I can think of
1- air bubbles in the valves (bleed, again),
2 - type of tyres, and tyre pressure,
3 - pollution in the hydraulic system,
4 - height sensors with loose linkages or unstable signal (worn carbon trace).
Malleus
Far west of Siegen
yes, tons of work and didn't help
No, I haven't yet changed body mount bushings.
To put things in perspective, I've got a 2003 Sequoia on an Eibach 1" lift that has all poly urethane bushings in the front end. It still sucks up minor road variations SO MUCH better than the LX.
To put things in perspective, I've got a 2003 Sequoia on an Eibach 1" lift that has all poly urethane bushings in the front end. It still sucks up minor road variations SO MUCH better than the LX.
@uHu , maybe you know the answer on this. Only the vgrs equipped have a steering angle sensor. I did some logging on my MY'99 and it shows a reading for the steering angle with a value of 85.5 degrees. Is this a default value if it doesn't see the sensor, or not equipped? Or am I entirely wrong and all MY100's have the sensor? Unless Toyota used different terminology, I have been thru the FSM/EWD and found nothing of the sort.
I to have the high speed rebound damping issue. Just figured I was due for some basic fluid maintenance as it's been a while.
My numbers are a bit low 5.8/6.0 but that's because I was set-up with a lot more weight that has since been removed.
However, I noticed that the damping concern is not consistent and seems to respond to me toying with the damping switch.
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Have you bled each corner recently to check for air bubbles?
One of the guys on here last year or 2023 maybe had new globe(s) fail soon after install. Bleeding a while after install generally makes that obvious. Not a common thing, but it can happen.
Malleus
Far west of Siegen
Just to be clear, I'm referring to the bushings between the body and frame, not the suspension components, upper/lower control arms, etc. Removing these bushings, except for the front and rear corners, isn't that much work, IMO.
Just wondering, because I replaced these on my 80 and it made a noticeable difference. Granted, it doesn't have AHC, but still...I'm trying to plan PM for my 2000 LX470 before it goes off to live a new life with my son after college.
Yes, the body mounts bushings. There were 8, maybe 10 of them? It has been a while and while they weren’t the hardest thing to change out it was definitely time consuming and there was no perceived improvement in ride quality. I did this after changing out ever other suspension bushing. Upper and lower control arms, sway bar bushings, steering rack, trans mounts, transfer case, engine mounts, etc.
Malleus
Far west of Siegen
Thanks for the reply. This is good to know information. Can you share how many miles you have on your truck and what tires you have?
182k. It’s had this issue since 130k or so. Consistently regardless of tire, e rated ko2, p metric at3, c rated Toyo mt currently.
uHu
Bridgeburner
If you have AHC, you have a steering angle sensor. On cars without vgrs, it's very easy to reset the sensor. Just make sure to have the steering straight, then unplug and replug the sensor, and reset fault code.
So I looked into the SAS this afternoon. Didn't use Techstream but used the Autel unit at our shop. Baseline reading showed approx -85'.
I unplugged the sensor while observing the data and it didn't flatline or throw a fault. However, I was able to get it to zero out by removing the steering wheel, spinning the sensor until it read zero, unplugged it to hold the zero value, re-centered, and plugged back in. Now reads '0' with the wheel centered.
I will say I feel a noticeable difference in the high speed bump response and absorbs them a bit better now. Definitely not as harsh as it was before.
Could use a good fluid flush and some pressure tweaks and I think it'll be near perfect.
Thank @uHu
Alot of good information here!
I have a 99 mod 4,2 diesel with 407000kms on it that have some issues with the AHC when the outside temperatur drops under 0°celcius. Then it gets this bumpy ride-feeling, and the AHC OFF light is blinking in the dashboard. After 10 minutes of driving things get back to normal and the heightlevel sets correctly.
I have new coils, new rear oem hydraulic dampers (old where leaking) and new fluid in the system. I get 7-8 marks fra H to L in the fluidtank.
Thinking of replacing all four globes. Is that the way to go?
Could it be that the gaslevel is low, and get even lower in cold temp?
I have a 99 mod 4,2 diesel with 407000kms on it that have some issues with the AHC when the outside temperatur drops under 0°celcius. Then it gets this bumpy ride-feeling, and the AHC OFF light is blinking in the dashboard. After 10 minutes of driving things get back to normal and the heightlevel sets correctly.
I have new coils, new rear oem hydraulic dampers (old where leaking) and new fluid in the system. I get 7-8 marks fra H to L in the fluidtank.
Thinking of replacing all four globes. Is that the way to go?
Could it be that the gaslevel is low, and get even lower in cold temp?
