trdcorolla
SILVER Star
Don't the King springs bring down the pressures by 2-3? I think you would be a good candidate and if your pressure is too low after the Kings, maybe give yourself a small sensor lift to get you back in spec?
The ABCs of AHC - How to Measure, Flush, and Adjust all in one place (12 Viewers)
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I would get King Springs. If pressure is too low, give yourself a tiny sensor lift. Being a little low on pressures is better than a little high, IMO.
If you don't want to go for Kings, I'd add spacers with your existing springs. The rear springs don't wear down too much from my mental tracking of folks that have swapped for new. New springs help, just not much. Spacers help a little more and Kings help a lot.
- Thread starter
- #103
Update: added @suprarx7nut's excellent video and cheat sheet to the early posts in this thread as well as some basic research I've done about different AHC mods.
Finally changed my AHC fluid over the weekend. Thank you very much for the guides. Fluid was black, similar to most pictures you'd see here. I didn't adjust torsion bars yet, but my pressures are all pretty good last time i checked last month when i was curious.
I had 9.5 grads before flush and about 9-9.5 after the flush, so no change there. It took a couple days of driving to really "feel" the difference, and wow, it's very noticeable between settings. I do about 90% highway driving, and had usually kept it in Sport 1 or normal (2nd setting). I find myself now putting it in sport 1/sport 2 when i know i have to change lanes a bunch or take turns since it really tightens things up. Comfort setting (first setting) to me is almost too "floaty" for the highway now. Overall I'm very happy with the improvement...will do another flush next year most likely.
I had 9.5 grads before flush and about 9-9.5 after the flush, so no change there. It took a couple days of driving to really "feel" the difference, and wow, it's very noticeable between settings. I do about 90% highway driving, and had usually kept it in Sport 1 or normal (2nd setting). I find myself now putting it in sport 1/sport 2 when i know i have to change lanes a bunch or take turns since it really tightens things up. Comfort setting (first setting) to me is almost too "floaty" for the highway now. Overall I'm very happy with the improvement...will do another flush next year most likely.
Great thread! Thanks to all.
One question:
I could not bleed my driver's side rear globe because of rust. The 10 m wrench could not grip the bleeder so i just left it alone. All of the other globes/ accumulator were able to be bled fully.
How necessary is bleeding each globe if they are connected side to side? Wouldn't bleeding the pass rear clean out most of the lines that lead to the rear globes?
One question:
I could not bleed my driver's side rear globe because of rust. The 10 m wrench could not grip the bleeder so i just left it alone. All of the other globes/ accumulator were able to be bled fully.
How necessary is bleeding each globe if they are connected side to side? Wouldn't bleeding the pass rear clean out most of the lines that lead to the rear globes?
It is worth doing the 16-step test just to be sure that nothing strange is happening at each individual corner. It is also worth being confident that the Front and Rear Levelling Valves are operating properly – you can do the “Active Test” for this but good evidence also is that the vehicle ‘shuffles’ upwards normally, alternately at Front and Rear, when rising from “LO” to “N”. You can also use Techstream to watch the signals sent by the ECU to the levelling valve solenoids during the rise – watch ‘SLRL’ (for Solenoid Rear Levelling) and ‘SLFL’ (for Solenoid Front Levelling) on the Techstream read-out during the rise. This operation also can be heard/felt at the Control Valve Assembly. Checking that the Gate Valves actually are working correctly is more tricky because the ECU uses speed, steering and other inputs. Watching ‘SLRG’ and ‘SLFG’ on Techstream while someone else is driving and turning sharply at speed may give an indication.
Anyway, assume that all relevant valves are working correctly. If so, then the Gate Valves remain open when the vehicle is travelling in a straight line, OR, when the vehicle is at rest. The hydraulic connections then are as shown below, except that when the "LO" or "HI" button is pressed on the console switch, the Levelling Valves open and the vehicle falls, or rises with pump operation, as required.
Ideally, the bleed is done at “LO” so that as much as possible of the old fluid in the ‘shock absorbers’ is returned to the AHC tank for removal. At “LO”, more weight is supported by the front torsion bars and rear springs (because of their greater deflection) and less weight is carried by the AHC system. If the ‘globes’ are in good condition (meaning that most of the nitrogen is still in place behind the diaphragm), then more fluid will be pushed by the nitrogen pressure behind the diaphragm out of the ‘globe’ and back to the AHC tank for removal. Fresh fluid is then added while vehicle is raised by AHC Pump, to refill the components. This is not a perfect process – which is why the process is repeated until clear new light red fluid can be bled from system.
If one ‘globe’ cannot be bled, then it is hard to be sure what fluid movement from it actually has taken place -- especially if the ‘globe’ is only in moderate to poor condition and the nitrogen pressure behind the diaphragm in the ‘globe’ is weak.
However, even with this limitation, possibly imperfect bleeding of the system is far, far better than not doing it all.
It does make sense to go through the usual AHC check-and-adjust sequence in the correct order:
- Check the static front ‘cross-levelling’ of the vehicle and adjust if necessary with Torsion Bars adjusters, and then,
- Check the operating front and rear hub-to-fender distances and adjust if necessary with Height Control Sensor adjusters, and then,
- Check the Front and Rear AHC neutral pressures and adjust at Front with Torsion Bar adjusters and deal with over-pressure at Rear with new springs or spacers, or at least recognise and make allowances for the situation, and then,
- Check overall condition of globes using difference in graduations observed at AHC Tank between “LO” and “HI” height settings (~14 = as new; ~7 = time to change ‘globes’). NOTE 1: If this check is done with AHC pressures too high because the AHC system is carrying excess share of vehicle weight, then the nitrogen pressure behind the ‘globe’ diaphragm will return less than expected AHC fluid to the tank and the observation will be erroneous. This test has to be done at correct AHC neutral pressures to be comparable with FSM specifications. NOTE 2: Low graduations in a correctly done test indicate that nitrogen pressures behind the diaphragms in the ‘globes’ are weak and unable to push the expected amount of fluid back to the tank. NOTE 3: This test does not identify any single faulty ‘globe’, only indicates overall deterioration, but the 16-step test may reveal differences between each corner of the vehicle.
Source: https://lc100e.github.io/manual/
then follow the index tabs starting right at the top:
New Car Features > CHASSIS > Suspension > Active Height Control Suspension.
Last edited:
- Thread starter
- #107
Agree with Indro overall. Most of the front or rear bleeding comes from the first globe you do. Hence only getting small amounts of fluid out when you switch sides according to the bleeding procedure that's been posted here. Obviously, bleeding all 4 corners is better than 3, which is better than none. I wouldn't fret over it too much. At the same time, some PB Blaster followed by locking pliers instead of a wrench have been successful for me in cracking stuck bleeders. Best to replace it with a new bleeder if you do get it off.
Hello All!
I’m a new to to AHC. Just installed a techstream. On my ‘03 Land Cruiser’JDM’ with a 2UZ-FE, the ride is extremely uncomfortable. The suspension is very stiff and i can feel each and everything. My car doesn’t go up to ‘hi’ mode, it blinks 2 times and stops. Hooked up techstream and the neutral pressures are stated as ‘0’ both front and rear.
Please somebody help me out what to do in this situation. The heights are almost good.
In this situation and can’t do a gradation test as it doesn’t go upto ‘hi’.
Can anyone please help me out? I’m really sick of driving it like this. Thanks
Here’s my techstream info:
I’m a new to to AHC. Just installed a techstream. On my ‘03 Land Cruiser’JDM’ with a 2UZ-FE, the ride is extremely uncomfortable. The suspension is very stiff and i can feel each and everything. My car doesn’t go up to ‘hi’ mode, it blinks 2 times and stops. Hooked up techstream and the neutral pressures are stated as ‘0’ both front and rear.
Please somebody help me out what to do in this situation. The heights are almost good.
In this situation and can’t do a gradation test as it doesn’t go upto ‘hi’.
Can anyone please help me out? I’m really sick of driving it like this. Thanks
Here’s my techstream info:
Sounds like you probably have very high neutral pressures. To get pressures readings, you have to hook up your reader, then go from L to N and record the numbers. The system doesn't give "live" info.
uHu
Bridgeburner
You have a
Hello Everybody - First post after reading all the threads for weeks. Very valuable so far for my build just getting under way. Thanks to the tire discussion just got 5 - 275-70R-18 Nitto G2 Terra Grapplers. No rubbing with AHC stock and working great on a mint 2001 LX470 I paid $7,000.00 for recently. So I have 13K build budget. Got a RigD Multi Fit tire carrier, full length 76” Rhino Pioneer rack platform with full side rails and wind spoiler. 2300.00 ouch. This per and winch next. car is perfect in and out (Garage kept in CA) but want some lift and would like the front a bit more even to the rear. I have read everything from adjusting AHC to stay in H, Slee override (discontinued?) to indexing/cranking stock torsion bars. Even Slee and other spring spacers will be considered. I don’t want to rip out a pristine AHC but need some lift. 1”-2” Or more and not throw anything off. It’s not I don’t want to spend I just like everything now.
Anybody in CA/AZ you can recommend to adjust AHC? Or install/get a Slee AHC device and play with my torsion bars and keep the integrity/alignment. I am retired and can drive and hire the right person. Thanks in advance I know this has been covered but it’s too complicated for me. Any Experts? Front bumper and winch next but stuck here.
Anybody in CA/AZ you can recommend to adjust AHC? Or install/get a Slee AHC device and play with my torsion bars and keep the integrity/alignment. I am retired and can drive and hire the right person. Thanks in advance I know this has been covered but it’s too complicated for me. Any Experts? Front bumper and winch next but stuck here.
What's the purpose for the lift need? 2" off-road too little? Hitting obstacles? Looks?
Why do you "need" 1"-2" of lift? The AHC high mode will give you that on demand when the conditions require it. If you just like the look of a higher lift, I believe you can accomplish at least some of that through adjusting the height sensors.
trdcorolla
SILVER Star
Don't forget to baseline your 100. If you decide to keep your AHC you need to watch your weight/AHC pressures to keep the system working properly.
Thanks for responding. Yes some lift strictly for looks and more aggressive stance. The more I read it seems I just need to be happy with my stock height and avoid adding a bunch of weight. The stock system works well.
10-4. New guy question.....is Baseline what you do when you plug in and get all the pressures? If yes then I probably need to find a guy. Thanks for the help and i will be avoiding too much weight added.
Yeah, I think you've got it. If it's just for looks you really need to consider how much that very slight change in looks is worth to you. A small (<1") sensor lift is free and relatively safe. It does make it more critical that you have the system in good shape, though. Neutral pressures are key. Once you get a handle on pressures and verify good fluid/globe health you can creep up on the sensor lift, but jumping right into 1"+ and just hoping the AHC can keep up is a recipe for disappointment, IMO.
Baseline meaning overall vehicle health. IE Don't add a lift kit/sensor lift if you've failed to review all the basics. Screwing around with a lift when you've got $2,500 in upcoming repairs because a few things are worn out is the fast-track path to "This stupid thing costs too much to drive, I'm going to go sell it and trade for a Wrangler with 37's on craigslist."
ramangain
Clarksonian disciple
Baseline (typically means) when you change fluids/filters/etc to set a known service mileage on the things you don't know about due to past service history, or want to install your brand-specific fluids/filters/etc. In reality, the sky is the limit (or your credit card limit) since you can baseline all of the rubber bits (hoses, bushings) and bigger ticket electrical/mechanical items too (starter, alternator, TB/WP, pulleys, steering rack, power steering pump, radiator, globes on AHC vehicles, spark plugs, coil packs, valve cover gaskets, UCA/LCA, tie rod ends, etc).
uHu
Bridgeburner
Something is not working with your TechStream or with the AHC. Which Trouble Code do you have? (Your TechStrem page says there is one)
Does it move from Lo to N? And still no movement in the pressure readings?
Do the height sensor numbers change when you go from Lo to N?
What about actual heights - are they at spec?
That the damping step numbers are fixed on 8 could indicate that you are in "limp mode". You could check the pressure sensor on the pump. Do you have the FSM?
Also, if the TBs have not been adjusted for a year or more, you can safely tighten them a few turns, to make it lighter for the ahc to lift.
