Diagnose and fix AHC (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Feb 12, 2021
Threads
3
Messages
26
Location
.
Hi everyone,

First post here. I just bought a 1999 LX470 and I am trying to work out first steps to getting it back to good functioning order. My initial plan was to swap out the AHC because it is not currently working. The truck rides very low and there is no AHC fluid in the reservoir. I figured the most simple and easy thing to do would be to just switch it out with an Iron Man or OME suspension. But I'm starting to think it's worth at least trying to get the AHC working again. I know next to nothing about the AHC suspension so I have no idea where to even start troubleshooting and trying to get it back to working order. I have Toyota AHC fluid coming in the mail. What should my first steps be to assess how serviceable the system is and what it would take to get it back running?


LX470.jpg
 
Add fluid to reservoir, bleed system and check for function and ride/height improvements.....
 
Last edited:
Definitely investigate. AHC is much nicer than those conventional alternatives and the fix for AHC is likely to be cheaper and less labor.

Very simple first things:

Fill the reservoir just past max with new fluid.
Crank the torsion bars 5 turns each (clockwise).

See if it will try to move. If not, bleed the system. You likely have air trapped in there and it can take some time to get it out. Easy task, just tedious.

Get yourself Techstream or another tool that can read AHC values (not just a standard cheap OBD scanner).

If all the components are there and it's not rusted to hell, AHC is generally easy and inexpensive to repair, contrary to myths of times gone by. We can help you source components from vendors with minimal markup.

Investigate for leaks from the AHC lines/components. If it's run dry of fluid, chances are it's leaking from somewhere.
 
Okay so I went out and took closer look at it. The fluid lines are actually disconnected from the shocks so it seems like someone had tried to start the AHC delete. I can't think of any other reason the fluid would be empty and the lines would be disconnected. Is it worth trying to figure out? Or should I just go ahead with the delete?
 
Investigate for leaks from the AHC lines/components. If it's run dry of fluid, chances are it's leaking from somewhere.
I just checked and the lines are not connected to the shocks anymore. I'm going to get it up on some stands and try to get a good look in the wheel well and see if I can get them back on and then put the fluid in and everything.
 
I just checked and the lines are not connected to the shocks anymore. I'm going to get it up on some stands and try to get a good look in the wheel well and see if I can get them back on and then put the fluid in and everything.
It's worth a shot. It is somewhat common for people to get [irrationally] scared out of their minds with AHC and give up without any investigation. Make sure the line connections are as clean as you can possible get them. You might need an o-ring (or 12).

I'm anxious to see where this goes!

Any chance you can get info from the PO? Just undoing the lines isn't helpful, so I wonder what they were thinking.
 
Are the globes and tube accumulator still installed?
 
It's worth a shot. It is somewhat common for people to get [irrationally] scared out of their minds with AHC and give up without any investigation. Make sure the line connections are as clean as you can possible get them. You might need an o-ring (or 12).

I'm anxious to see where this goes!

Any chance you can get info from the PO? Just undoing the lines isn't helpful, so I wonder what they were thinking.
The PO I bought from only had the car about 2 weeks because he got it in a trade and was just trying to get rid of it. I'm anxious to see too! I'll take a look today or tomorrow and let you guys know what I find.
 
And you're sure the shocks are the AHC shocks?
I can't tell but I am pretty sure. It's sitting too low to really be able to see much right now. Tomorrow I will limp it over to my friend's house who has jack stands so I can get a better look at what's going on. Just bought 3 liters of AHC fluid so let's hope I can put it to use. I actually already ordered an Iron Man suspension last week but if I can get the AHC working I'll just keep it on the AHC and return the new suspension or hold onto it until the AHC breaks. I have lots of small things to fix up on the car to get it to baseline so I'll take savings where I can get them.
 
I can't tell but I am pretty sure. It's sitting too low to really be able to see much right now. Tomorrow I will limp it over to my friend's house who has jack stands so I can get a better look at what's going on. Just bought 3 liters of AHC fluid so let's hope I can put it to use. I actually already ordered an Iron Man suspension last week but if I can get the AHC working I'll just keep it on the AHC and return the new suspension or hold onto it until the AHC breaks. I have lots of small things to fix up on the car to get it to baseline so I'll take savings where I can get them.
The Ironman suspension is garbage for a stock car (that is without a good 5-600 pound load at least). Fix the AHC.
 
How is the ride as of right now? AHC shocks that don't have fluid in the AHC system will ride like a early 90s Civic with 3/4s of the spring cut out. It will be absolutely bumpy as hell and pretty much undrivable.

Is it that bad, or is there some actual damping in the suspension?
 
How is the ride as of right now? AHC shocks that don't have fluid in the AHC system will ride like a early 90s Civic with 3/4s of the spring cut out. It will be absolutely bumpy as hell and pretty much undrivable.

Is it that bad, or is there some actual damping in the suspension?
It's bad like you described
 

Users who are viewing this thread

Back
Top Bottom