AHC Bouncy & Stiff Front End (1 Viewer)

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The timing on this thread is awesome. My 07 has no shock absorption after a bump in the road or after going over a speed bump. I'm not mechanically inclined so I work with a local shop. For the most part I used a Toyota dealer but they have become more interested in getting their commissions than actually working with me on what needs to be done. With that said, would you all suggest shocks, etc or should I look into something else. Sorry to highjack this stream of info but you all really seem to have a handle on this issue. Thanks in advance.

Do you have AHC or conventional? For AHC, it's impossible to diagnose without knowing the "health" of the system. You'd need Techstream or an iCarSoft TYT reader to get the pressures. One thing you could do would be to run a graduation test. Don't need any tools for that.

Put vehicle in Low. Once rig settles and stops moving, pop hood and observe the AHC reservoir (passenger side firewall in engine bay). There are "graduation" marks on the reservoir. Take note of what mark the fluid is at. Shut the hood, return to the driver seat and cycle the AHC to Neutral/Normal. Once it settles and stops moving, pop hood and observe the AHC reservoir again. Take not of what mark the fluid is now at. If the total difference in marks between the two settings less than 8, you're looking at a compromised system. 14 marks would be brand new. Most consider "healthy" to be 9-11 marks.
 
The timing on this thread is awesome. My 07 has no shock absorption after a bump in the road or after going over a speed bump. I'm not mechanically inclined so I work with a local shop. For the most part I used a Toyota dealer but they have become more interested in getting their commissions than actually working with me on what needs to be done. With that said, would you all suggest shocks, etc or should I look into something else. Sorry to highjack this stream of info but you all really seem to have a handle on this issue. Thanks in advance.

Would need to know a lot more about your setup currently. 07 LX I assume? Are you in the same boat as the OP with AHC removed? Do you have AHC torsion bars or replaced with something else? What shocks?
 
Do you have AHC or conventional? For AHC, it's impossible to diagnose without knowing the "health" of the system. You'd need Techstream or an iCarSoft TYT reader to get the pressures. One thing you could do would be to run a graduation test. Don't need any tools for that.

Put vehicle in Low. Once rig settles and stops moving, pop hood and observe the AHC reservoir (passenger side firewall in engine bay). There are "graduation" marks on the reservoir. Take note of what mark the fluid is at. Shut the hood, return to the driver seat and cycle the AHC to Neutral/Normal. Once it settles and stops moving, pop hood and observe the AHC reservoir again. Take not of what mark the fluid is now at. If the total difference in marks between the two settings less than 8, you're looking at a compromised system. 14 marks would be brand new. Most consider "healthy" to be 9-11 marks.
Looks like the difference was 3 marks.
 
Would need to know a lot more about your setup currently. 07 LX I assume? Are you in the same boat as the OP with AHC removed? Do you have AHC torsion bars or replaced with something else? What shocks?
07 Toyota LC. AHC system installed.
 
Looks like the difference was 3 marks.

Go all the way to High and then let us know what that delta is between Low and High. I originally meant to say go from Low all the way to High and then measure. Odds are, you're probably looking at 7 graduation marks between Low and High.
 
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First off, I really appreciate your time. The difference is 4. A note, in N the fluid is 2 marks below minimum.
 
First off, I really appreciate your time. The difference is 4. A note, in N the fluid is 2 marks below minimum.

If from L to H you only have a difference of 4 graduations, your AHC globes are shot. This would certainly explain your poor ride. They're about $1000 in parts to replace so you'll have to decide if that vs an aftermarket non-AHC suspension is a better investment.
 
First off, I really appreciate your time. The difference is 4. A note, in N the fluid is 2 marks below minimum.

YIKES! 4 is a failed system. Sounds like the fluid was never maintained and you've got a potential leak somewhere. What is the color of the fluid in the reservoir? Should be pink. Curious what the fluid in the system looks like. You could always do a quick drain and refill if you wanted (would cost less than $60). Just need a few bottles of AHC fluid. My money is on a blown globe. I bet if you cracked one of the bleeders and drained some fluid, you'd see a dark, foamy fluid which would indicate a failed globe.

I've seen it all when it comes to AHC. I've seen people who have put brake fluid in the system, windscreen washing fluid in the system, coolant in the system and more. Most of the time, they simply drive and drive and drive and never once maintain the system. It really should be drained and refilled every 30k to maintain it.
 
It's been a while but I think when I flushed my AHC fluid the first time the fluid was pink (when the fluid was in the 2.5L metal can) but when I did it a 2nd time (the single quart bottles) the fluid was amber. Or it could be the other way around.
 
It's been a while but I think when I flushed my AHC fluid the first time the fluid was pink (when the fluid was in the 2.5L metal can) but when I did it a 2nd time (the single quart bottles) the fluid was amber. Or it could be the other way around.

You have it the other way around. AHC fluid is a light pink.
 
Yikes is right. My fluid is brown. I'm guessing a call to Toyota service is my next step.

Honestly, I'd just order 3 bottles of AHC fluid and do a flush and refill at home and see where that gets you. It's a straight forward job and I am happy to walk you thru the process. Generally takes 20 minutes to complete a full drain/fill. Brown fluid is definitely OLD. I bet when you bleed one of the globes, you're going to see foam. You are most likely facing either replacing the globes (about $900) or replacing the suspension to conventional (about $1k in parts). Either way, a drain/refill might buy you some time.
 
Honestly, I'd just order 3 bottles of AHC fluid and do a flush and refill at home and see where that gets you. It's a straight forward job and I am happy to walk you thru the process. Generally takes 20 minutes to complete a full drain/fill. Brown fluid is definitely OLD. I bet when you bleed one of the globes, you're going to see foam. You are most likely facing either replacing the globes (about $900) or replacing the suspension to conventional (about $1k in parts). Either way, a drain/refill might buy you some time.
This is good advice since your globes are already worn out. Clean fluid now and if you swap out the globes later you'll feel better having clean fluid running through them. I had around 5-6 grad in my LX when I got it, it rode pretty good (not pogo stick feeling yet). The pogo feeling happened after I flushed the fluid. I was mad that I spent the money on the first flush but realized when I changed my globes, clean AHC fluid was the only fluid the new globes saw, not whatever fluid was in there from the prior owner. Before you go spending money, these grad tests are only really valid when your AHC pressures are in the proper range.
 
This all has given me so much knowledge and prepared me to almost as much as the dealer/service department. Changing the fluid first is a great idea. I'm taking it in tomorrow. I'll keep you all posted.
 
This all has given me so much knowledge and prepared me to almost as much as the dealer/service department. Changing the fluid first is a great idea. I'm taking it in tomorrow. I'll keep you all posted.

You can do this!!
 
Before adjusting tbars or replacing fluid, etc. I'd say adjust the sensors so the hub center to bumper distance are factory and the sensors don't disagree that much. That'll give you new pressure readings & reveal if you have a bad sensor or two. If the height is set correctly and the sensors are reading correctly only then go further with other things. Just my $0.02
 
Hey everyone, I recently had my mechanic reindex my t-bars and this was the outcome when I checked the pressure levels....


EF47D636-59EC-4CFC-83CF-663F50420543.jpeg
 
Update: the Toyota Regional Master Tech was in the shop same time as me/my Cruiser. After having a look he recommended going back with a solution that bypasses the AHC. There are several rusty parts that look impossible to open/repair. In his words, "it's a can of worms you don't want to open."
 

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