My nagging "issue" with AHC is wondering if the suspension doesn't feel quite right. I feel bumps pretty well and I subjectively recall an older 100 series land cruiser standard suspension feeling like being on a cloud vs the small cracks in the road. The question is driving me insane when I'm on the road..
I've read what seems like every AHC topic on here over the past few months before and after my LX470 purchase. Knowledge is there but spread around.
I'd like to replace the major AHC wear items short of the globes and it would be very useful to confirm these steps in one post, for myself and others as well wondering about their suspension.
Here's what I've come up with for the most bang for the buck: please let me know if you'd add or remove anything / change ordering, etc. For the record, my LX is at 117k miles.
First you would want to diagnose if you have a problem with your AHC.
Unfortunately, the only test I know of is to check if your globes are bad via the "Height Test".
I have no way of knowing whether the other components are bad or if my ride is standard / okay. I just have a gut feeling that it can be improved. At worse, you'll be extending the life of your AHC by reducing wear on it.
AHC height test.
Put vehicle in LOW. Mark fluid level in AHC reservoir.
Put vehicle in HIGH.
Number of graduations (ticks) on the reservoir from LO to HI should be at least 7. If less, your globes are shot and it's very expensive to replace.
I personally get 14 or so so it appears they are in great condition.
Assuming those globes are fine, it's time to start working:
Flush AHC fluid.
https://forum.ih8mud.com/100-series-cruisers/438560-ahc-fluid-change-how-need-input.html#post6127557
Cost: $40 / can. Need 2.
Dealer charge around $200-250.
Difficulty: Easy.
Result: Many report increased ride quality. I didn't notice so much when the dealer did it. I am going to buy 2 cans and flush it till it's clean.
Test neutral pressure / crank torsion bars accordingly
Neutral pressure is the pressure of the AHC system at each wheel in the N position. The AHC system is designed to carry a certain load while the torsion bars in the front / coils in the rear pick up the rest.
My dealer refuses to check the neutral pressure for me saying it's only what crazy enthusiasts do so I've found a product called the Tactrix Open Port 2.0 which can read the pressures.
Once you have the pressures up front, you'll be able to crank the torsion bars until the AHC system is carrying the correct load. Others blindly do 3-6 cranks every 5 years.
Here's a post from somebody who cranked Tbars based on neutral pressure data: https://forum.ih8mud.com/100-series-cruisers/529309-measure-ahc-neutral-pressure.html
Cost: $100-200 used/new for Tactrix Open Port 2.0 Cable There's a $35 alternative discussed below; waiting for reports.
Cost at dealer: they cowardly refuse.
Result: Haven't done it yet. Hopefully noticeable.
Replace Rear Coil Springs
The neutral pressure test will probably show the rear AHC pressures too high due to age of the rear coils.
Posts on mud suggest 5 years max before rear AHC starts going over spec on load.
Anything else in this rear suspension setup I should replace?
Part numbers:
48231-6A730
48231-6A740
Cost: ~$200 for parts.
Cost at dealer / mechanic: ?
Result: haven't done it yet.
My hope is that after these changes I'll have done as much as I can (without spending too much) for my ride.
Any comments, additions, etc. appreciated.
I've read what seems like every AHC topic on here over the past few months before and after my LX470 purchase. Knowledge is there but spread around.
I'd like to replace the major AHC wear items short of the globes and it would be very useful to confirm these steps in one post, for myself and others as well wondering about their suspension.
Here's what I've come up with for the most bang for the buck: please let me know if you'd add or remove anything / change ordering, etc. For the record, my LX is at 117k miles.
First you would want to diagnose if you have a problem with your AHC.
Unfortunately, the only test I know of is to check if your globes are bad via the "Height Test".
I have no way of knowing whether the other components are bad or if my ride is standard / okay. I just have a gut feeling that it can be improved. At worse, you'll be extending the life of your AHC by reducing wear on it.
AHC height test.
Put vehicle in LOW. Mark fluid level in AHC reservoir.
Put vehicle in HIGH.
Number of graduations (ticks) on the reservoir from LO to HI should be at least 7. If less, your globes are shot and it's very expensive to replace.
I personally get 14 or so so it appears they are in great condition.
Assuming those globes are fine, it's time to start working:
Flush AHC fluid.
https://forum.ih8mud.com/100-series-cruisers/438560-ahc-fluid-change-how-need-input.html#post6127557
Cost: $40 / can. Need 2.
Dealer charge around $200-250.
Difficulty: Easy.
Result: Many report increased ride quality. I didn't notice so much when the dealer did it. I am going to buy 2 cans and flush it till it's clean.
Test neutral pressure / crank torsion bars accordingly
Neutral pressure is the pressure of the AHC system at each wheel in the N position. The AHC system is designed to carry a certain load while the torsion bars in the front / coils in the rear pick up the rest.
My dealer refuses to check the neutral pressure for me saying it's only what crazy enthusiasts do so I've found a product called the Tactrix Open Port 2.0 which can read the pressures.
Once you have the pressures up front, you'll be able to crank the torsion bars until the AHC system is carrying the correct load. Others blindly do 3-6 cranks every 5 years.
Here's a post from somebody who cranked Tbars based on neutral pressure data: https://forum.ih8mud.com/100-series-cruisers/529309-measure-ahc-neutral-pressure.html
Cost: $100-200 used/new for Tactrix Open Port 2.0 Cable There's a $35 alternative discussed below; waiting for reports.
Cost at dealer: they cowardly refuse.
Result: Haven't done it yet. Hopefully noticeable.
Replace Rear Coil Springs
The neutral pressure test will probably show the rear AHC pressures too high due to age of the rear coils.
Posts on mud suggest 5 years max before rear AHC starts going over spec on load.
Anything else in this rear suspension setup I should replace?
Part numbers:
48231-6A730
48231-6A740
Cost: ~$200 for parts.
Cost at dealer / mechanic: ?
Result: haven't done it yet.
My hope is that after these changes I'll have done as much as I can (without spending too much) for my ride.
Any comments, additions, etc. appreciated.
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