AHC Sensor Adjustment for Lift (5 Viewers)
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great article and I can't wait to try that, however there are plenty of follow ups & replies on this thread discussing the need to tighten the torsion bars in order to get the "pressure" of the AHC closer to oem specs. I believe that the truck has to be plugged into some sort of software to read this right? can someone offer a bit more detailed info on that?? I am a new owner and coming from a solid front axle rig, this torsion bar stuff and AHC is a bit like voodoo (I am from New Orleans, I should know Voodoo). ThanksAdjusting your AHC sensors are fairly easybanana: job). You'll need to furnish/fabricate a simple bracket extension which I'll cover in step 5. You'll also need one can of AHC fluid from Toyota $22/can. (part # 08886-01805). I have heard the exact fluid costs more if bought from Lexus.
1. Take measurements of your ride height at each corner of the vehicle. I recommend measuring from the fender lip to the bottom wheel lip.
2. Turn off ignition. Jack up the front, secure with a jack stands and remove your front wheels. Locate the Height Control Sensor as seen in the diagram. Note the position on the adjustable top mount. You are going to want to slide it up as far as possible in the next step.
3. I found it easiest to just remove the top nut of the heim joint (10mm) and adjust the rod so that it is as short as possible. This will give you about 2" of lift in the front. If you want 2.5", you'll have to shorten the heim joint (I used a cut-off wheel) and then used the existing stop-nuts to "smooth out the thread" and actually remove the stop nuts completely. Be careful because one side is a reverse thread. Not many people I know have a reverse cut tap/die set.
Once done, reinstall the heim joint and adjust it so that the Height Control Sensor lever is as high as possible. Remount the wheels. You can readust the sensor through the wheel-well later. Make sure ALL adjustments are done while the vehicle is OFF for safety reasons!
4. After the front sensor adjustments are done and all jacks are cleared away, you can start the engine. All the doors, hatch and hood need to be closed for the AHC to work. This adjustment will yield up to 2.5" of lift in the front.
5. Now for adjusting the rear. Again, make sure ignition is off. No need to remove the wheels, just crawl underneath and locate the Height Control Sensor. There is only one for the rear. If you slide the adjustment to the top, you'll gain about 1.75" of lift. For more, you'll have to extend the mount 2" or so. I used 1" aluminum flat stock and drilled two holes (to mount to the existing bracket) and slotted a 3rd hole for adjustability. If you space out the aluminum stock from the old bracket 3/16" of so, you can get better adjustability.
6. Fill Reservoir with AHC Fluid to correct level. It is also a good time to flush the system if its never been done before. Lexus recommends a flush every 60k miles. How to flush AHC fluid thread: Changing out the AHC suspension fluid?
After you get the height you want, you'll want to get an alignment job. If you haven't already installed a differential drop bracket, now is a good time.
About AHC HI/N/LO modes: if you raise the front 2", you'll still be able to go into HI mode. If you raise the front suspension 2.5", the AHC system will raise and then come back down to N mode. I suspect the suspension is "topping-out" and so it reverts back to N mode. However, you'll be able to adjust to LO mode at any lift height.
I noticed a slight increase in ride firmness. I'm not sure if it is because the increased angle of the A-arms or the increase in AHC fluid suspending the vehicle or if it's just all in my head. But the Ride Comfort adustments work fine after this mod.
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Edit: Perhaps more important than the amount of lift is the amount of droop left in the suspension. If you lift too much, your suspension (shocks) will "knock" (top-out) when going over bumps. Here's some advice from ATS4X4:
You should maintain a minimum of 70mm [2.75"] of droop in the 100 IFS front set up, if you have a Slee diff drop fitted, to stop the cv boots wearing out. [boot pleats shouldnt be touching in straight ahead position at ride height]. This is normally 50-60mm higher than standard, depending on accessory levels. On a 16" rim this makes for 770mm [30.3"] measurenent from bottom of rim bead edge up through centre of wheel to fender edge when set up correctly. Rear should be aprox 790-800mm [31.5"]
View attachment 37153
Read pressures using techstream
How-To: TechStream In 5 Minutes
Getting Techstream up and running can be a bit of a pain. Hopefully this helps someone get started quickly. Step 1: Purchase an OBD-II / Mini-VCI interface. - I have sold out of my cables and supply chains are back in order, so no reason to purchase more. Anything like this will work: Mini-VCI...
forum.ih8mud.com
99 LX470 stock... Just did only the sensor adjustment by sliding the bolt to the top of the bracket on the front..... resulted in 5/8 lift of front end... the back was already at the top of the bracket.... almost level front to back now.... side to side is a different story.... 5/8 lower on drivers side... I had no idea I had put on that much weight
I had airbags installed in the rear springs years ago for towing a heavy trailer which we dont do aymore..... I have been running without any pressure for the last few years. Does anyone know if I can get a little height in the rear, maybe 1" by just adding pressure? I have searched but did not see any reference to the lift heights acheived... seems like it might be a cheap and easy was to add height, and load bearing capacity at the same time.....
You can not.
hi after reading this i’m interested in trying this out but i’m kinda stuck since i don’t know exactly which part of it to alter does anyone have a video or pics of the process? i took some images and maybe these are the pieces i need to adjust? any help is great thanks all
BullElk
SILVER Star
I haven't used the air bags on any LX but I have them in my '99 LC. I don't know what the psi is right now but it gives me a nice lift of about 2". Rides great and really like it.
Here is what to do if you don't want to cut anything.
A: remove the nut so that the top of the joint is free.
B: loosen these two nuts and unscrew until they are touching the "nut" in the middle of the two.
C: screw these further into the thread (basically screw them so that they get closer to the middle where the nuts are).
Eventually you won't be able to turn them any further. Once they are as close as they will go, back the "B" nuts back into them to lock them in place.
Hope that makes sense. There are three of these to adjust. One under each front wheel well and one in the rear.
Thank you so much i was lost just by looking at it!
one more question when do i screw A bolt back on ?
This is a good step by step.
forum.ih8mud.com
2-2.5" AHC Lift Using King Coils & Shock Spacers
Well all my parts finally showed up and this past weekend I lifted my LX. My goal was to have a 2-2.5" lift (using the AHC system), while keeping close to stock travel characteristics and stock neutral pressures. Components Installed: KING KTRS-79 Coils (sourced from eBay seller sparesbox_auto)...
forum.ih8mud.com
thanks a lot i really appreciate it sir!
Tomorrow i will attempt this. however when adjusting the torsion bars are their any precautions to take?? ive read the following:
leaving the car on the ground (wheels)
have the front wheels raised (front Jacked)
loosen the UCA so torsion bars arent maxxed out
im not sure which is accurate since ive read many ways to do it. Whats the best way?
thanks i plan on recording this process.
leaving the car on the ground (wheels)
have the front wheels raised (front Jacked)
loosen the UCA so torsion bars arent maxxed out
im not sure which is accurate since ive read many ways to do it. Whats the best way?
thanks i plan on recording this process.
Leave the vehicle on the ground when adjusting torsion bars.. Put the AHC in high mode before tightening torsion bars to make the torsion bars easier to adjust. Then put AHC back in neutral height to read your pressures.
I use a socket on my impact and put a piece of tape on the side so I can count revolutions. It's a pain in the butt to turn the screw by hand. Also a good time to put some anti-seize on it while you're there.
Thamks, thats pretty smart!
I don't go to the gym anymore, so I leave it in N and do it by hand. I then count that as my workout for the month.
The UCA loosening comments would be valid for the non-AHC cars where changing the torsion bars modifies the vehicle height and you need to ensure you don't twist a bushing and wear it out quickly. On AHC cars, the torsion bar has nothing to do with ride height, so the UCA and LCA can be left alone.
The UCA loosening comments would be valid for the non-AHC cars where changing the torsion bars modifies the vehicle height and you need to ensure you don't twist a bushing and wear it out quickly. On AHC cars, the torsion bar has nothing to do with ride height, so the UCA and LCA can be left alone.
