LX570 AHC Globe/Accumulator Replacement
- Thread starter NKP Garage
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lol. Yeah, ive tried various little things since my driveway is steep.
Fill on incline, fill on decline, drop doing both, visa versa etc.
One thought i am entertaining though, easy access, while i thought may wear out things, couldnt have been put in to the detriment of AHC, perhaps, it has protective value in purging things like bubbles, and cycling “used“ fluid back into the 5th and mixing with fresher ststuff on restart.
I may start using it more.
I'll echo what most everyone said. Your symptoms do line up with accumulator failure. Shock failure commonly happens shortly after accumulator failure because the system essentially becomes hydraulically locked with compromised or bottomed out globes. There are no codes that detect this failure mode.
Bubbles in the system are not likely as it runs at very high pressures and seems self purging to some degree. That would only result in a softer ride. Damping valve failures would not be it either as that would again be a softer ride, perhaps with less control, and usually has a code.
Look on Ebay for OEM globes from Japan, with super high ratings. Many of us have sourced globes from there at a fraction of the cost. Super fast shipping.
32cls6speedmt
SILVER Star
I ordered accumulators from JDM Planet | Auto Parts - https://jdm-planet.com. Great price
I have not installed yet since mine are working well.
I have not installed yet since mine are working well.
$330.67 US for 4 globes!
$330.67 US for 4 globes!
Shipping to high though.
Thread '‘Spring rubbers’ LX570 missing link for attitude control on normal builds (non long travel)'
‘Spring rubbers’ LX570 missing link for attitude control on normal builds (non long travel) - https://forum.ih8mud.com/threads/spring-rubbers-lx570-missing-link-for-attitude-control-on-normal-builds-non-long-travel.1300261/
My theory is that the stiffer spring rate will allow your ahc more overhead to manage attitude. Probably in your case just a patch for the accumulators, but cheap and easy to find out.
I still think it’s a bad bleed, but 10 years is the assumed service life on the accumulators.
We'll see; my 2013 LX is right @ 10yrs (only 71k miles though) AHC fluid changed at 60k. Working perfectly now.
Hello again,
As promised i would give updates regarding my issue. I ended up replacing all 4 accumulators it rides much better, smoother and handles well. All i can say is if any of you reading this are experiencing rough ride and if changing the AHC Fluid does not fix the ride quality, changing the accumulator is the way to go.
Many thanks, to all of you here, i followed the DIY Video provided and finished up the job together with a friend who is a mechanic in less than an hour.
There are a few questions i would like to ask, maybe some of you here can chime in and give input.
1. Right after the installation and everything was bled properly. We went for a test drive, in N (Normal/Neutral) it felt a bit firm and the next day it softens a bit more. Is this normal?
2. Had a few hours of spare time today and decide to test out the suspension in light off-roading condition. Nothing extreme, just some dirt surfaces with wheel articulation/suspension travel. Had in in H (High) and Comfort. It feels as though the suspension would all of a sudden over-damp or holding too much pressure. It was not smooth going over large bumps and humps. Its as if its confused choosing the right pressure on each wheel.
3. When going from N to H, does the car need to be on level ground? It took a while to lift up when it was not level and would not come down to N directly. After restarting the car and moving to a more flat surface it would return back to N and was slanted to the left. I cycled the suspension height then it was leveled out.
Thanks guys hopefully some of you who are experienced with the AHC system in the 200 series LX/LC can provide input.
As promised i would give updates regarding my issue. I ended up replacing all 4 accumulators it rides much better, smoother and handles well. All i can say is if any of you reading this are experiencing rough ride and if changing the AHC Fluid does not fix the ride quality, changing the accumulator is the way to go.
Many thanks, to all of you here, i followed the DIY Video provided and finished up the job together with a friend who is a mechanic in less than an hour.
There are a few questions i would like to ask, maybe some of you here can chime in and give input.
1. Right after the installation and everything was bled properly. We went for a test drive, in N (Normal/Neutral) it felt a bit firm and the next day it softens a bit more. Is this normal?
2. Had a few hours of spare time today and decide to test out the suspension in light off-roading condition. Nothing extreme, just some dirt surfaces with wheel articulation/suspension travel. Had in in H (High) and Comfort. It feels as though the suspension would all of a sudden over-damp or holding too much pressure. It was not smooth going over large bumps and humps. Its as if its confused choosing the right pressure on each wheel.
3. When going from N to H, does the car need to be on level ground? It took a while to lift up when it was not level and would not come down to N directly. After restarting the car and moving to a more flat surface it would return back to N and was slanted to the left. I cycled the suspension height then it was leveled out.
Thanks guys hopefully some of you who are experienced with the AHC system in the 200 series LX/LC can provide input.
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This will definitely affect changing heights in terms of both speed and the truck indicating that it fully changed heights. For example, my driveway is sloped, when I raise the truck it will clearly raise, flash, but never indicate high mode until I get on level ground.
If you are experiencing inconsistent dampening it might be worth another bleed.
Noted and thanks, I will try another bleed. Inconsistent dampening indeed... it was like as if the suspension all of sudden became stiff then back to soft then stiff again.
Right. I do have another 2,5 liter fluid ready, will try to bleed it again. Also I forgot to mention when raising the car from N to H it's quick. However from L to N it takes a long while now.
I discovered a little trick with the AHC display.
If your ride height changes and does not confirm in dash, open the door, select low, normal, and back to high (it wont change with the door open, but the dash will pretend to cycle), now close door and 8 times out of ten, it will show H everytime.
And yes @KRR there are certain lockouts depending on multiple factors, one of them being g sensor.
Is this a good place to talk about actual effect of having air in the system? I should preface all this will, if i was asked, I think I can definitely feel after doing a component change that the ride is harsher and eventually smooths out after bleeding/driving around. But in theory you should always be able to put numbers to what we are experiencing.
Let's start with some data:
Brief background. The fronts have all 3 chambers acting at normal driving and shuts off the No. 1 chamber when in curves and during braking to stiffen up the front end. The rear always has both chambers acting on the actuator. The other piece to the puzzle is that all 4 corners can act on each other's individual system pressures.
Situation A:
Let's say you let 200cc of air into the system at 1 bar (atmospheric pressure at sea level-ish). This could be your typical changing out a component, so the system has become completely decompressed, but you sealed it back up with air in it.
Now you start the truck up and push the vehicle up to 8 MPa (assuming functioning OEM system)
By Boyles law that 200cc of air is now 2.5 cc of air. The #1 gas chamber should now be at a volume of 95cc (at the rear, so i can avoid the math for gas chamber 2)
In affect you will have added a 2-3% (2.5cc/95cc) increase in volume of the No. 1 Gas chamber.
How much difference do we think that makes? Or am i missing something? I know that I'm essentially ignoring the force on the system from gravity (the ground pushing the actuator back into the system). But i'm having trouble wrapping my head around that.
Its easier to think of a system with only 1 force acting on it, but in reality, if you are looking at each corner of the trucks systems individually, there are inputs from:
A. The center control cylinder
B. Each of the Gas chambers (3 for front and 2 for rear)
C. Gravity acting on the shock actuator back into the system.
D. Any air that might be in the system.
Let's start with some data:
| No. 1 Gas Chamber | Front | Rear |
| Sealed Gas | Nitrogen | Nitrogen |
| Gas Chamber Volume | 24.4 In^3 (400cc) | 24.4 In^3 (400cc) |
| Sealed Gas Pressure | 2.26 MPa | 1.90 MPa |
| Relief Gas Chamber | ||
| Sealed Gas | Nitrogen | Nitrogen |
| Gas Chamber Volume | 7.3 In^3 (120cc) | 9.2 In^3 (150cc) |
| Sealed Gas Pressure | 13.5 MPa | 10 MPa |
| No. 2 Gas Chamber | ||
| Sealed Gas | Nitrogen | |
| Gas Chamber Volume | 7.3 In^3 (120cc) | |
| Sealed Gas Pressure | 1.8 MPa |
Brief background. The fronts have all 3 chambers acting at normal driving and shuts off the No. 1 chamber when in curves and during braking to stiffen up the front end. The rear always has both chambers acting on the actuator. The other piece to the puzzle is that all 4 corners can act on each other's individual system pressures.
| Vehicle Condition Fluid Temperature | Fluid Temperature Condition | Reference Value |
| When vehicle height changes from NORMAL to HI | 20°C (68°F) +/-10°C (50°F) | The oil pressure begins rising when control is started and reaches approximately 13 MPa (132.6 kfg/cm2, 1885 psi) when the vehicle height is almost finished changing to HI. |
| When vehicle height changes from LO to NORMAL | 20°C (68°F) +/-10°C (50°F) | The oil pressure begins rising when control is started and reaches approximately 8 MPa (81.6 kfg/cm2, 1160 psi) when the vehicle height is almost finished changing to NORMAL. |
Situation A:
Let's say you let 200cc of air into the system at 1 bar (atmospheric pressure at sea level-ish). This could be your typical changing out a component, so the system has become completely decompressed, but you sealed it back up with air in it.
Now you start the truck up and push the vehicle up to 8 MPa (assuming functioning OEM system)
By Boyles law that 200cc of air is now 2.5 cc of air. The #1 gas chamber should now be at a volume of 95cc (at the rear, so i can avoid the math for gas chamber 2)
In affect you will have added a 2-3% (2.5cc/95cc) increase in volume of the No. 1 Gas chamber.
How much difference do we think that makes? Or am i missing something? I know that I'm essentially ignoring the force on the system from gravity (the ground pushing the actuator back into the system). But i'm having trouble wrapping my head around that.
Its easier to think of a system with only 1 force acting on it, but in reality, if you are looking at each corner of the trucks systems individually, there are inputs from:
A. The center control cylinder
B. Each of the Gas chambers (3 for front and 2 for rear)
C. Gravity acting on the shock actuator back into the system.
D. Any air that might be in the system.
- Thread starter
- #297
Interesting read
Question for you, did you examine any of the globes you took off? Like did you check the depth of the diaphragm to see if anywhere abnormally lacking pressure? I had my globes off last year to see if they needed replacement and all the diaphragms were where they should be so I didn’t bother replacing but the ride if rougher then I believe it should be on this truck.
Wait, i thought the rears were charged higher than the fronts?
There’s some math there I’m having trouble wrapping my head around.
The higher spring rate No2 chambers also have a lower charge pressure . It is also a smaller volume.
I assume there is something I’m not wrapping my head around that the lower charged gas spring makes for a higher spring rate. The only thing off my dome I could come up with is that the spring would be activated at a lower pressure, so possibly that’s why it creates a higher spring rate.
