Trying to make a decision on my AHC for 2004 LX 470

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ctjambo

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I just purchased a 2004 LX 470 131K miles, from a Lexus dealership from out of state and the vehicle was stated to have gone through a full 154 point inspection. Upon driving the vehicle over rougher roads away from the dealership there was a very bouncy ride. I then brought the vehicle to a separate Toyota dealership to diagnose the issue and they stated all four shocks were leaking, left front being the worst. They also stated, Height Control Fluid activated which may have issue, need to replace all four shocks and alignment. Quoted $4200.

I have had the AHC cycle through the all three stages when sitting in park with no issues, but the ride is very bouncy when going over an overpass or slight bumps. I have read that there could be other steps to take besides tearing out the whole system, but trying to decide how much money to throw at saving the AHC system, compared to switching to a new "static" suspension. This is my first vehicle of this type and I am looking to be able to go out on trails but not to the extreme degree. Any advice as to which route to take from individuals that might have already had this issue?
 
BullElk

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There are others here that can give you better info but… AHC “shocks” may weep fluid normally with no need of replacing. A leaking “shock”, like loosing all the AHC fluid onto the ground leaking, may need to be replaced. However it is not a common occurrence to replace AHC shock/hydraulic pistons. I did have one replaced once that cost about $140 for the part.

My experience with a bouncy ride is the nitrogen globes being the culprit. That is an expensive job at all dealership but really a fairly easy job to do. You can get the four globes at a few non dealership vendors for around $700-800.
 
suprarx7nut

suprarx7nut

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Step 1: Consider that the dealership diagnosis is likely wrong. Leaking shocks may just mean they're all over pressure or the top Oring has failed. Needing all 4 new shocks is highly irregular.
Step 2: Read this thread and watch the video below. The ABCs of AHC - How to Measure, Flush, and Adjust all in one place - https://forum.ih8mud.com/threads/the-abcs-of-ahc-how-to-measure-flush-and-adjust-all-in-one-place.1211999/
Step 3: Check neutral pressures or find someone near you that knows how.
Step 4: Check gradations in the reservoir to determine if the globes are shot (they probably are).
Step 5: Replace globes as needed, flush the fluid and go from there. Be aware there was a bizarre stint of plastic bottles of AHC with gel in them. You shouldn't run into that right now, but it wouldn't hurt to inspect any fluid you buy. If the system is functioning perfectly, but the globes are worn out, it will ride horribly. Simple failure, simple fix.

Unless the system is badly rusted or you have a strong aversion to DIY work, I would forget the concept of removing AHC. For moderate use, that's like amputating a finger over an ingrown nail. The system is generally robust and the common failure points are well understood and DIY friendly.

 
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ctjambo

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There are others here that can give you better info but… AHC “shocks” may weep fluid normally with no need of replacing. A leaking “shock”, like loosing all the AHC fluid onto the ground leaking, may need to be replaced. However it is not a common occurrence to replace AHC shock/hydraulic pistons. I did have one replaced once that cost about $140 for the part.

My experience with a bouncy ride is the nitrogen globes being the culprit. That is an expensive job at all dealership but really a fairly easy job to do. You can get the four globes at a few non dealership vendors for around $700-800.
Thank you for the quick response, I had two responses that believe it is the globes so I will start there
 
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ctjambo

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Step 1: Consider that the dealership diagnosis is likely wrong. Leaking shocks may just mean they're all over pressure or the top Oring has failed. Needing all 4 new shocks is highly irregular.
Step 2: Read this thread and watch the video below. The ABCs of AHC - How to Measure, Flush, and Adjust all in one place - https://forum.ih8mud.com/threads/the-abcs-of-ahc-how-to-measure-flush-and-adjust-all-in-one-place.1211999/
Step 3: Check neutral pressures or find someone near you that knows how.
Step 4: Check gradations in the reservoir to determine if the globes are shot (they probably are).
Step 5: Replace globes as needed, flush the fluid and go from there. Be aware there was a bizarre stint of plastic bottles of AHC with gel in them. You shouldn't run into that right now, but it wouldn't hurt to inspect any fluid you buy. If the system is functioning perfectly, but the globes are worn out, it will ride horribly. Simple failure, simple fix.

Unless the system is badly rusted or you have a strong aversion to DIY work, I would forget the concept of removing AHC. For moderate use, that's like amputating a finger over an ingrown nail. The system is generally robust and the common failure points are well understood and DIY friendly.


Thank you for the quick response, I will start with the globes and hope that is the issue
 
bamabrock

bamabrock

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Unless you need considerable extra payload or your AHC system is rusted out, I'd correct the AHC pressures and then replace globes if needed.
 
Fisher67

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Saw this video and it made me laugh, but reminded me of why the AHC system is so awesome. Citroen system also uses globes and was good enough for Rolls Royce to use. Always have felt AHC makes the 100 ride like a caddy.


 
Z

Zer0zg

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Saw this video and it made me laugh, but reminded me of why the AHC system is so awesome. Citroen system also uses globes and was good enough for Rolls Royce to use. Always have felt AHC makes the 100 ride like a caddy.



Same thing went through my mind when I watched that. Showed my wife, she didn't seem as impressed...
 
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ctjambo

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I bought brand new globes for $850, but I was able to keep those in the box, because I was able to switch out all four of my globes with globes off of another system. I got great help from Jess over at Gray Industries Cruisers. He deleted a system for someone else but was still operable. I bought the used parts off of him and with a little bit of instruction was able to change the globes myself. When taking off the globes, only the front two did not pass the pencil test but I went ahead and replaced all of four of them. I added 2.5 liters of suspension fluid and tested the system and it went from 4 graduated units to 11. Took it for a drive and it was super smooth and floated, no more pogo sticking. Dealership told me $4200...Used globes, fluid and a little bit of a mess...$225. I was able to find everything I needed on this forum, so thank you all very much for your assistance.
 
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MuddSlideSlim

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If you want some nearly new globes for cheap, PM me and we can work it out. They have about 12k miles on them, but I deleted AHC last January and they've just been riding along ever since.
 

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