I’ll replace the globes soon ish. I’ll get them from impex in Japan and deal with the long delivery times to save $300 a piece
Props to PADDO's AHC fluid replacement method!
- Thread starter Clunky
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IndroCruise
SILVER Star
The ultimate test of 'ride quality' is the 'backside test' -- how it feels personally. If happy, then delay 'globe' replacement until unhappy -- but damping is unlikely to be as good as it can be.
As @BullElk highlights, the HI/LO graduation test gives an overall result for the four 'globes' all together. All four 'globes' are unlikely to collapse simultaneously, but like tyres and brakes, when one has reached the 'wear point' the others are likely to be not far behind, so trying to target one or two bad 'globes' in a ~20 years old set of four can be an exercise in futility.
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^^^^ Agree....If unexperienced in the globe replacement process, I would suggest replacing all or having all replaced at same time.
Yep I’ll be doing all 4 at the same time.
Is replacing the globes really as easy as it looks (according to YouTube videos)? It looks like it’s basically a fluid flush, but with 1 extra step, being twisting the spent globes off and outing the new ones on before starting the truck and refilling the system
Is replacing the globes really as easy as it looks (according to YouTube videos)? It looks like it’s basically a fluid flush, but with 1 extra step, being twisting the spent globes off and outing the new ones on before starting the truck and refilling the system
It is not difficult but I think one needs to get a couple under their belt before describing as easy. There can be frustrating events like rusty or corroded globe connections making retrieval difficult or not keeping enough fluid in reservoir duriing bleeding and then getting air in system. But it is usually a fairly easy uneventful job. That is why I personally would do 1-2 globes at a time if I knew others were still good. I don't mind the work.
IndroCruise
SILVER Star
A 2006 LX470 in Texas with only 186,000 miles seems likely to be in good underbody condition -- none or very little rust seizing parts together?
@BullElk has summed it up succinctly as usual. Here is a bit more .....
Yes -- 'globe' replacement should be a simple and quick process, although the first time can be 'interesting'! Mostly, the 'globes' come off easily with a thin but strong 36mm wrench to match the fitting on the 'globe' and a long handle for leverage. Sometimes 'globes' can be very tight and difficult to remove. Some war stories and solutions can be found in various IH8MUD threads including the one below:
Cannot remove AHC Globe - https://forum.ih8mud.com/threads/cannot-remove-ahc-globe.1359385/
Attaching four new 'globes' means that a LOT of air has been introduced into the AHC system and a persistent, methodical and repetitive approach to bleeding is essential -- but is not difficult. There are various approaches to this but the already used "PADDO" method is a good place to begin -- attached again for convenience.
This forum is replete with frustrated war stories of bleeding going wrong after 'globe' replacement or other AHC repairs (such as replacement of the AHC Pump sub-assembly or troubles with the Height Control Accumulator), usually due to additional air being inadvertently allowed to enter during the process. The solution is more and more and more bleeding. So it is a good idea to have at least two 2.5 litre cans of genuine Toyota/Lexus AHC Fluid Part Number 08886-01805 on hand before starting -- stay with the knowns, avoid suggestions of other fluids, some of which are destructive of parts of the AHC system. Remnant air left in the AHC system will result in a very spongy 'ride quality' and much unhappiness. Avoid using the 1 litre plastic bottles of AHC Fluid Part Number 08886-81221 which were marketed in the USA in past years and which are said to contain or degrade to a gel which causes blockage problems.
It can happen that the AHC Pump refuses to start if it contains air and if so, it will need to be re-started. Sometimes this can be done using the "HEIGHT CONTROL OPERATION TEST -- ACTIVE TEST" per Section 5 at Page 6 of the first attachment (Special Service Tool SST 09843-18020 is simply a piece of bridging wire and a bent paperclip is just as good!) Ignore the array of dashboard lights which will show during this method.
If the Active Test cannot be made to work, then make a brief (10 seconds) direct connection from the battery to the AHC Motor, ensuring correct polarity so that the motor rotates in the correct direction.
Strongly recommend reading enough of the thread at the link below to get an undertstanding of the AHC and TEMS systems and what to do when common problems are encountered, including watching the video at Post #5:
If not seen before, the attached General Description of the AHC and TEMS systems is a worthwhile read.
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Tagging also @PADDO @suprarx7nut all three of you have helped so much our ahc community and would love your advice if I should add on new springs or spacer and what kind OR just leave as is with my pressures being front 6.1(not as loaded)-6.2 (loaded out)A 2006 LX470 in Texas with only 186,000 miles seems likely to be in good underbody condition -- none or very little rust seizing parts together?
@BullElk has summed it up succinctly as usual. Here is a bit more .....
Yes -- 'globe' replacement should be a simple and quick process, although the first time can be 'interesting'! Mostly, the 'globes' come off easily with a thin but strong 36mm wrench to match the fitting on the 'globe' and a long handle for leverage. Sometimes 'globes' can be very tight and difficult to remove. Some war stories and solutions can be found in various IH8MUD threads including the one below:
Cannot remove AHC Globe - https://forum.ih8mud.com/threads/cannot-remove-ahc-globe.1359385/
Attaching four new 'globes' means that a LOT of air has been introduced into the AHC system and a persistent, methodical and repetitive approach to bleeding is essential -- but is not difficult. There are various approaches to this but the already used "PADDO" method is a good place to begin -- attached again for convenience.
This forum is replete with frustrated war stories of bleeding going wrong after 'globe' replacement or other AHC repairs (such as replacement of the AHC Pump sub-assembly or troubles with the Height Control Accumulator), usually due to additional air being inadvertently allowed to enter during the process. The solution is more and more and more bleeding. So it is a good idea to have at least two 2.5 litre cans of genuine Toyota/Lexus AHC Fluid Part Number 08886-01805 on hand before starting -- stay with the knowns, avoid suggestions of other fluids, some of which are destructive of parts of the AHC system. Remnant air left in the AHC system will result in a very spongy 'ride quality' and much unhappiness. Avoid using the 1 litre plastic bottles of AHC Fluid Part Number 08886-81221 which were marketed in the USA in past years and which are said to contain or degrade to a gel which causes blockage problems.
It can happen that the AHC Pump refuses to start if it contains air and if so, it will need to be re-started. Sometimes this can be done using the "HEIGHT CONTROL OPERATION TEST -- ACTIVE TEST" per Section 5 at Page 6 of the first attachment (Special Service Tool SST 09843-18020 is simply a piece of bridging wire and a bent paperclip is just as good!) Ignore the array of dashboard lights which will show during this method.
If the Active Test cannot be made to work, then make a brief (10 seconds) direct connection from the battery to the AHC Motor, ensuring correct polarity so that the motor rotates in the correct direction.
Strongly recommend reading enough of the thread at the link below to get an undertstanding of the AHC and TEMS systems and what to do when common problems are encountered, including watching the video at Post #5:
If not seen before, the attached General Description of the AHC and TEMS systems is a worthwhile read.
and rear 6.4 (not as loaded) 6.9 (loaded out).
Goal: to keep brand new Toyota globes running well and not get early wear and tear. Originals lasted 27 years with 299k miles and still membranes in tact still after pencil test! But gave 8 tick marks on reservoir test only for past two years even after fluid changes. No pogo stick feeling was happening. Drove well. Now have 14 tick marks on new globes test.
And heights in spec and been using YOTAMD’s Suprarx great cheat sheet and video. Heights for wheel to fender listed below.
Question regarding pressures and if my 6.9 in rear too high for brand new globes when car loaded out with baby car seats and some tools (rear third row ONE seat in only, so I guess we could say that weight removal helps but then offset by car seats etc). Car all stock no added weight on outside.
Pressure checked with various weight scenarios using tech stream (pics attached):
A) test with full tank of gas and then done WITHOUT any child car seats (3 totaling 115 lbs) and tools not in car (50lbs) and no passengers inside. One third row seat out and only one in.
Front pressure: 6.1 at various flat locations
Rear pressure: 6.4 at various flat locations
With oil temperature sensor off. BUT sometimes when it’s off it registers very low out of no where with rear or front dropping to 3.4 front or 2.5 rear! It’s odd on tech stream. Will show briefly pressures in 6ish and then both drop to some low number. Never have issue when temp sensor is on. That’s always consistently in 6ish. Some times it’s fine with temp sensor off also and registers still in 6ish range just like when it is on but often it goes to also random 3-2 range for both front and back.
B) test same as above BUT with oil temperature sensor put on.
Front pressure: 6.1 at various flat locations
Rear pressure: 6.4 at various flat locations
C) put in two car seat (76 lbs total)
Front pressure: 6.2 at various flat locations
Rear pressure: 6.5- 6.9 at various flat locations
With oil temp sensor off and also on (except times it gave random readings of 2-3 pressures for front and rear)
D) put in 3 car seat (114 lbs total) plus about 50 lbs of tools. Full tank of gas still. Fully loaded minus any passengers or me inside.
Front pressure: 6.2 at various flat locations
Rear pressure: 6.9 consistently at various flat locations
With oil temp sensor off and also on (except times it gave random readings of 2-3 pressures for front and rear)
HEIGHTS
Front wheel center to fender height on both front wheels: 19.5 inches
Rear height wheel center to fender on both real wheels: 20.5 inches
Same height now post globe change as before on old globes.
I don’t think I can change pressure using torsion bars anymore since heights are in spec and front is leveled. No cross tilt like when I fixed it three years ago. I don’t think I can raise them any higher properly where both fronts stay same height. They are in spec but happy to try something if you think I can and lesson pressure on rear a bit that way?
Some more info
Brand new front upper and lower Toyota control arms put in 3k miles ago. And lower bushings for front ahc struts. New front sway bar links also. Haven’t done sway bar bushings in front. Rear have brand new upper and lower control arms from Toyota on shelf and same with the sway bar links for rear. And new AHC rear shocks and AHC rear lines on shelf too. ONLY place I have RUST on entire vehicle is on ends (6 inches) of rear ahc lines and bracket ends). Think it was caused by exhaust leak previous owner took too long to fix. Had burned wires for comfort mode on passenger wheel. I fixed them and got comfort mode back. But that high heat and a fuel tank leak under previous owner probably caused the corrosion on rear ahc lines last 6 inches. No rust anywhere else under car. Joy to work on. Let me know if new rear ahc shocks, rear control arms etc somehow helps with pressures and I’ll install them in near future.
I also changed fluid out 2 years ago myself according to Paddo’s method. Have never had issue with ahc pump running dry. This time when changing globes and bleeding I noticed the rear driver side globe gave out frothy fluid BUT may have just been pressure at first because in bottle there was only one kind of dark fluid once all settled from all globes. I was expecting the rear globes then to be busted and membranes popped but all four passed the pencil test at 27 years old and 299k miles on them. Date stamped 12/1998.
New ones are now date stamped 06/2025 and have NGK engraved on them. Originals from
Impex Japan.
ORIGINAL 12/1998 springs still in rear.
SHOULD I LEAVE THIS AS IS WITH THE PRESSURES I SEE OR GO CHANGING REAR SPRINGS TO AHC ORIGINALS or something else? Worried if I do KING springs they’ll knock off rear pressure too much as I saw some say they will be for heavier builds and knock down pressure almost 3 points. So was thinking originals again for AHC models. Hard to find new for right side but possibly found one new from japan. Left hand is easy to find. I could possibly do these when I do rear upper and lower control arms install and when I do rear new ahc shocks and ahc line install.
Not sure how strong the LC original springs are compared to AHC originals in terms of how much pressure they’ll knock off. As of now I don’t have plans to mod this car with heavier parts like bumpers, winch, armor. Not for another few years until kids bit older. For now we just use it for family travel few times a week with three kids and the wifey (400lbs between 5 of us passengers). Plus the kids seats and some tools we are talking maybe like 550 lbs total in car on all stock parts. And third row one seat out. I think stock should be able to more than handle our weight but maybe oem 27 year old springs losing strength and putting more pressure on globes? Though I think 6.9 pressure on rear isn’t too bad but like I said I’d like to improve if possible if it means keeping overall ride quality and lessening pace of wear on new globes.
Or do spacers? I find spacers work from videos I saw seem almost as much work as putting in new springs and I might as well then do new springs. That’s what my feeling is right now. Open to suggestions.
Also happy to leave it as is if these pressures aren’t too bad to you? The rear is just at edge of out of spec and I’d like to make new globes last long.
RIDE LAST TWO DAYS AFTER NEW GLOBES
I find ride has improved maybe 50% over bumps, where u feel them maybe 50% more dampened with new globes which are going to 14 tick marks from eight tick marks on older globes. Not a crazy crazy improvement feeling wise while driving, some potholes or areas on the road here in Toronto (horrible roads), you still feel the jarring effect. But I have no pogo stick syndrome nor did I have it before. Overall glad I put on new globes and thank you all!
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IndroCruise
SILVER Star
LATE EDIT: To fix typos reported, and also, to add a link to further information highlighting how air in hydraulic fluid not only diminishes hydraulic performance due to spongey effects and cavitation damage at pump parts and valve orifices, but also degrades the fluid itself through fluid breakdown, formation of sludge etc. These effects generally highlight the importance of 'hydraulic hygiene' and the reason for regular AHC Fluid change-out per Owners Manual not less frequenlty than every 60,000 miles or each 6 years, and whenever major maintenance or component replacements are performed on the AHC/TEMS systems.
+++++++++++++++++++++++++++++++++++++++++
Wow!! The above post #287 by @WanderingWarrior is impressive and the understanding of the Active Height Control (AHC) and Toyota Electronically Modulated Suspension (TEMS) systems and the works already done and planned in the future are VERY comprehensive.
If I am understanding correctly, this ~27 years old vehicle is
· 1999 LX470 with 299k miles,
· in close to stock (ex-factory) specification,
· no significant additional build,
· still in overall good condition,
· AHC and TEMS are operating correctly,
· based in Toronto, Canada,
· an epic story of vehicle and AHC/TEMS longevity!!
Past AHC and TEMS maintenance and renovations have included:
· remediation of heat-damaged wiring,
· monitoring of surface rust in parts of AHC pipework,
· new Front Upper and Lower Control Arms,
· new lower bushings for Front AHC struts,
· new Front sway bar links,
· new Front and Rear ‘globes’ -- Toyota/Lexus genuine OEM items from IMPEX,
· genuine AHC Fluid change-out,
· Techstream monitoring of AHC and TEMS pressures and Height Control Sensor readings, AND,
· the all-important hub-to-fender tape-measurements of actual physical ‘ride heights’.
Items “on the shelf” for future work include:
· new Rear Upper and Lower Control Arms,
· new Rear Sway Bar Links,
· new Rear AHC ‘shocks absorbers’,
· new Rear AHC Pipelines.
Techstream Results – General:
All of the displayed @WanderingWarrior Techstream output looks good. A Diagnostic Trouble Code (DTC) is recorded as expected when the AHC Fluid Temperature Sensor is disconnected for testing as recommended per Factory Service Manual (FSM). Consistent pressure readings are obtained with Temperature Sensor connected.
It is unclear whether the occasional random effects on pressures relate to the vehicle itself (such as conflicts perhaps caused by aged sensors), or, the vagaries of the ‘borrowed’ Techstream software. Intermittent effects often indicate a loose connection somewhere or a partially broken wire.
Suggest only become concerned if ongoing inconsistencies are associated with other adverse AHC/TEMS symptoms on the vehicle and warrant further investigation.
It may be worthwhile to test the Pressure Sensor using the FSM procedure relevant to your Model Year. (Not all Pressure Sensors are the same – note the differences in connectors and test procedures. This is a deliberate change by Toyota/Lexus and it remains unclear whether the different Pressure Sensors are interchangeable even though the threaded fittings are the same).
The Pressure Sensor attached to the AHC Pump assembly is vital to AHC/TEMS operation and it is the only Pressure Sensor in the AHC/TEMS systems. Pressure Sensor faults are possible but are very unusual.
The Suspension Electronic Control Unit (ECU) uses voltage signals from Pressure Sensor to determine whether the load limits of the AHC system have been reached. These load limits are not described by specific pressures in Mpa in the FSM. Instead, the guidance below is provided in the FSM. ("Load limits" include everything in or on the vehicle -- people, baggage, fuel, accessories, everything -- which exceeds the vehicle condition when the Front and Rear AHC pressures are within the FSM-specified ranges).
The loadings described by @WanderingWarrior with young family are well within this FSM guidance and protective of ‘globe’ longevity -- at least for the time being.
If loadings are expected to increase with growing children or some form of vehicle build, then further adjustment (or even re-indexing) of Front torsion bars may be indicated, AND ALSO, the need for increased Rear coil spring load carrying capacity would be indicated and which can be achieved either by
· addition of spacers -- these provide minimum improvement, or,
· addition of Firestone airbags inside coil springs -- add air pressure in airbags only when required to match increased Rear suspension loading, otherwise hold at minimal 'shape-holding' of 5 psi -- https://www.firestoneairide.com/aut...market-air-helper-spring-kits/coil-rite-kits/, or,
· replacement with springs of higher spring rate, specifically KING KTRS-75 springs, as a permanent long term solution. [Replacement of like-for-like AHC coil springs may prove disappointing. Note that there are a variety of AHC coil springs -- it is worth searching “springs” and “@uHu” to gain some insights. All of the AHC coil springs are very light -- an innings of ~27 years is way long enough for the existing springs, they are well past their best!!]
The higher spring rate of the commonly chosen alternative KTRS-79 springs will cause a significant reduction in Rear AHC pressure, depending on actual vehicle loadings.
In the @IndroCruise case of a 'young' June 2006 vehicle, KTRS-79 springs resulted in an initial Rear AHC pressure of 5.0 Mpa. This was then off-set somewhat by a small ‘sensor lift’ (see pic) to increase Rear AHC pressure which is now 5.3 Mpa for a hub-to-fender height of 540mm (21.25 inches) while not allowing front-to-rear rake to become too excessive.
Front AHC Pressure is 5.7 MPa for a hub-to-fender height of 490mm (19.3 inches) -- this Front pressure could be increased with a small height increase to say 500mm (19.75 inches), which also would improve Front-to-Rear rake. This Perth-based LC100 vehicle with AHC is now in the hands of my son-in-law and does extensive duty loaded with pre-teen children and their equipment to sporting venues, or loaded for family camping expeditions along the backroads of Western Australia etc, for all of which it is perfectly and very comfortably suited.
The ride experience when empty (without these loadings) with KTRS-79 springs is slightly firmer than original but remains very acceptable -- no regrets. It feels as least as good as the ride experience in the @IndroCruise LC200 vehicle with KDSS (no AHC)!! Spacers have their place as a possible alternative, but would have been completely inadequate for the loadings experienced by the @IndroCruise LC100 with AHC/TEMS.
The ‘globes’ on the @IndroCruise vehicle were replaced in May 2019 (at 8 graduations overall) after only 183,231 kilometres (113,917 miles), probably adversely affected by long periods at excessively high AHC pressures which also included weeping ‘shock absorbers’ -- before the wisdom of IH8MUD was discovered -- so this experience was much, much, much worse than the @WanderingWarrior quoted ‘globe’ life experience!! [Six years later, with much closer attention to AHC/TEMS maintenance, the new-in-2019 ‘globes’ on the @IndroCruise LC100 vehicle still show ~14 graduations at the AHC Tank between “HI” height and “LO” height -- although vehicle usage has been very low at only 45,000 kilometres (28,000 miles) over that time].
The @WanderingWarrior goal already is in sight: “To keep brand new Toyota globes running well and not get early wear and tear. Originals lasted 27 years with 299k miles and still membranes in tact still after pencil test!”
‘Globe’ longevity is underwritten by controlling and maintaining AHC pressures within the FSM-specified ranges and maintaining ‘hydraulic hygiene’ (meaning clean bubble-free genuine AHC Fluid, changing-out 3.7 litres or 3.9 US qts or 3.3 lmp. Qts at least per Owners Manual every 60,000 miles or every 6 years – or better still, twice as often).
If and when increased vehicle loadings are envisaged, suggest respond early with matching Front torsion bar adjustment (or re-indexing) and upgraded Rear coil spring capacity to maintain AHC pressures within the FSM-specified ranges.
Some further comments ....
".... when changing globes and bleeding I noticed the rear driver side globe gave out frothy fluid".
Froth means bubbles and bubbles mean air in AHC Fluid. As with a soft drink bottle, the bubbles will not be visible in the fluid until the pressure is released -- cap taken off in the case of the soft drink bottle or bleeder valve opened in the case of the AHC system. A lengthy explanation can be found at the link below concerning how air in hydraulic fluid not only diminishes hydraulic performance due to spongey effects and cavitation damage at pump parts and valve orifices but also degrades the fluid itself through fluid breakdown, formation of sludge etc. These effects generally highlight the importance of 'hydraulic hygiene':
Removing Entrained Air in Hydraulic Fluids and Lubrication Oils - https://www.machinerylubrication.com/Read/373/entrained-air-oil-hydraulic.
The AHC Fluid -- Toyota/Lexus Part Number 08886-01805 -- is a light mineral oil -- no other fluid should be used in the AHC/TEMS systems without clear documented proof of comparable properties.
It seems likely that the @WanderingWarrior AHC/TEMS system and ride quality would benefit from further bleeding.
.
"Pencil Test" .....
As noted in your post #287 and for emphasis for other readers, the so-called "Pencil Test" is useful only to determine whether the membrane in a 'globe' is completely ruptured and the 'globe' has lost ALL nitrogen pressure. Newly installed 'globes' showing ~14 graduations at the AHC Tank in the HI/LO Test will have all or most of the factory-fill nitrogen pressure of 327psi or 2.26MPa (per FSM in the case of a Front 'globe'). If the HI/LO test readings at the AHC Tank (at FSM-specified AHC Fluid pressures and heights) have reduced to 7 or 8 graduations indicating time for 'globe' replacement, then the nitrogen pressure in the 'globe' still will be significant, possibly around 150psi or 1.03 MPa. Efforts to understand pressures in this case by pushing on the button on the membrane with a pencil will be meaningless -- like pressing on a tyre with a pencil to test tyre pressure (even at only 40psi or 0.28 Mpa).
"Items 'on the shelf' for future work" ....
As this work progresses, more bushes will be replaced and this will contribute to further improvement in ride quality.
+++++++++++++++++++++++++++++++++++++++++
Wow!! The above post #287 by @WanderingWarrior is impressive and the understanding of the Active Height Control (AHC) and Toyota Electronically Modulated Suspension (TEMS) systems and the works already done and planned in the future are VERY comprehensive.
If I am understanding correctly, this ~27 years old vehicle is
· 1999 LX470 with 299k miles,
· in close to stock (ex-factory) specification,
· no significant additional build,
· still in overall good condition,
· AHC and TEMS are operating correctly,
· based in Toronto, Canada,
· an epic story of vehicle and AHC/TEMS longevity!!
Past AHC and TEMS maintenance and renovations have included:
· remediation of heat-damaged wiring,
· monitoring of surface rust in parts of AHC pipework,
· new Front Upper and Lower Control Arms,
· new lower bushings for Front AHC struts,
· new Front sway bar links,
· new Front and Rear ‘globes’ -- Toyota/Lexus genuine OEM items from IMPEX,
· genuine AHC Fluid change-out,
· Techstream monitoring of AHC and TEMS pressures and Height Control Sensor readings, AND,
· the all-important hub-to-fender tape-measurements of actual physical ‘ride heights’.
Items “on the shelf” for future work include:
· new Rear Upper and Lower Control Arms,
· new Rear Sway Bar Links,
· new Rear AHC ‘shocks absorbers’,
· new Rear AHC Pipelines.
Techstream Results – General:
All of the displayed @WanderingWarrior Techstream output looks good. A Diagnostic Trouble Code (DTC) is recorded as expected when the AHC Fluid Temperature Sensor is disconnected for testing as recommended per Factory Service Manual (FSM). Consistent pressure readings are obtained with Temperature Sensor connected.
It is unclear whether the occasional random effects on pressures relate to the vehicle itself (such as conflicts perhaps caused by aged sensors), or, the vagaries of the ‘borrowed’ Techstream software. Intermittent effects often indicate a loose connection somewhere or a partially broken wire.
Suggest only become concerned if ongoing inconsistencies are associated with other adverse AHC/TEMS symptoms on the vehicle and warrant further investigation.
It may be worthwhile to test the Pressure Sensor using the FSM procedure relevant to your Model Year. (Not all Pressure Sensors are the same – note the differences in connectors and test procedures. This is a deliberate change by Toyota/Lexus and it remains unclear whether the different Pressure Sensors are interchangeable even though the threaded fittings are the same).
The Pressure Sensor attached to the AHC Pump assembly is vital to AHC/TEMS operation and it is the only Pressure Sensor in the AHC/TEMS systems. Pressure Sensor faults are possible but are very unusual.
The Suspension Electronic Control Unit (ECU) uses voltage signals from Pressure Sensor to determine whether the load limits of the AHC system have been reached. These load limits are not described by specific pressures in Mpa in the FSM. Instead, the guidance below is provided in the FSM. ("Load limits" include everything in or on the vehicle -- people, baggage, fuel, accessories, everything -- which exceeds the vehicle condition when the Front and Rear AHC pressures are within the FSM-specified ranges).
The loadings described by @WanderingWarrior with young family are well within this FSM guidance and protective of ‘globe’ longevity -- at least for the time being.
If loadings are expected to increase with growing children or some form of vehicle build, then further adjustment (or even re-indexing) of Front torsion bars may be indicated, AND ALSO, the need for increased Rear coil spring load carrying capacity would be indicated and which can be achieved either by
· addition of spacers -- these provide minimum improvement, or,
· addition of Firestone airbags inside coil springs -- add air pressure in airbags only when required to match increased Rear suspension loading, otherwise hold at minimal 'shape-holding' of 5 psi -- https://www.firestoneairide.com/aut...market-air-helper-spring-kits/coil-rite-kits/, or,
· replacement with springs of higher spring rate, specifically KING KTRS-75 springs, as a permanent long term solution. [Replacement of like-for-like AHC coil springs may prove disappointing. Note that there are a variety of AHC coil springs -- it is worth searching “springs” and “@uHu” to gain some insights. All of the AHC coil springs are very light -- an innings of ~27 years is way long enough for the existing springs, they are well past their best!!]
The higher spring rate of the commonly chosen alternative KTRS-79 springs will cause a significant reduction in Rear AHC pressure, depending on actual vehicle loadings.
In the @IndroCruise case of a 'young' June 2006 vehicle, KTRS-79 springs resulted in an initial Rear AHC pressure of 5.0 Mpa. This was then off-set somewhat by a small ‘sensor lift’ (see pic) to increase Rear AHC pressure which is now 5.3 Mpa for a hub-to-fender height of 540mm (21.25 inches) while not allowing front-to-rear rake to become too excessive.
Front AHC Pressure is 5.7 MPa for a hub-to-fender height of 490mm (19.3 inches) -- this Front pressure could be increased with a small height increase to say 500mm (19.75 inches), which also would improve Front-to-Rear rake. This Perth-based LC100 vehicle with AHC is now in the hands of my son-in-law and does extensive duty loaded with pre-teen children and their equipment to sporting venues, or loaded for family camping expeditions along the backroads of Western Australia etc, for all of which it is perfectly and very comfortably suited.
The ride experience when empty (without these loadings) with KTRS-79 springs is slightly firmer than original but remains very acceptable -- no regrets. It feels as least as good as the ride experience in the @IndroCruise LC200 vehicle with KDSS (no AHC)!! Spacers have their place as a possible alternative, but would have been completely inadequate for the loadings experienced by the @IndroCruise LC100 with AHC/TEMS.
The ‘globes’ on the @IndroCruise vehicle were replaced in May 2019 (at 8 graduations overall) after only 183,231 kilometres (113,917 miles), probably adversely affected by long periods at excessively high AHC pressures which also included weeping ‘shock absorbers’ -- before the wisdom of IH8MUD was discovered -- so this experience was much, much, much worse than the @WanderingWarrior quoted ‘globe’ life experience!! [Six years later, with much closer attention to AHC/TEMS maintenance, the new-in-2019 ‘globes’ on the @IndroCruise LC100 vehicle still show ~14 graduations at the AHC Tank between “HI” height and “LO” height -- although vehicle usage has been very low at only 45,000 kilometres (28,000 miles) over that time].
The @WanderingWarrior goal already is in sight: “To keep brand new Toyota globes running well and not get early wear and tear. Originals lasted 27 years with 299k miles and still membranes in tact still after pencil test!”
‘Globe’ longevity is underwritten by controlling and maintaining AHC pressures within the FSM-specified ranges and maintaining ‘hydraulic hygiene’ (meaning clean bubble-free genuine AHC Fluid, changing-out 3.7 litres or 3.9 US qts or 3.3 lmp. Qts at least per Owners Manual every 60,000 miles or every 6 years – or better still, twice as often).
If and when increased vehicle loadings are envisaged, suggest respond early with matching Front torsion bar adjustment (or re-indexing) and upgraded Rear coil spring capacity to maintain AHC pressures within the FSM-specified ranges.
Some further comments ....
".... when changing globes and bleeding I noticed the rear driver side globe gave out frothy fluid".
Froth means bubbles and bubbles mean air in AHC Fluid. As with a soft drink bottle, the bubbles will not be visible in the fluid until the pressure is released -- cap taken off in the case of the soft drink bottle or bleeder valve opened in the case of the AHC system. A lengthy explanation can be found at the link below concerning how air in hydraulic fluid not only diminishes hydraulic performance due to spongey effects and cavitation damage at pump parts and valve orifices but also degrades the fluid itself through fluid breakdown, formation of sludge etc. These effects generally highlight the importance of 'hydraulic hygiene':
Removing Entrained Air in Hydraulic Fluids and Lubrication Oils - https://www.machinerylubrication.com/Read/373/entrained-air-oil-hydraulic.
The AHC Fluid -- Toyota/Lexus Part Number 08886-01805 -- is a light mineral oil -- no other fluid should be used in the AHC/TEMS systems without clear documented proof of comparable properties.
It seems likely that the @WanderingWarrior AHC/TEMS system and ride quality would benefit from further bleeding.
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"Pencil Test" .....
As noted in your post #287 and for emphasis for other readers, the so-called "Pencil Test" is useful only to determine whether the membrane in a 'globe' is completely ruptured and the 'globe' has lost ALL nitrogen pressure. Newly installed 'globes' showing ~14 graduations at the AHC Tank in the HI/LO Test will have all or most of the factory-fill nitrogen pressure of 327psi or 2.26MPa (per FSM in the case of a Front 'globe'). If the HI/LO test readings at the AHC Tank (at FSM-specified AHC Fluid pressures and heights) have reduced to 7 or 8 graduations indicating time for 'globe' replacement, then the nitrogen pressure in the 'globe' still will be significant, possibly around 150psi or 1.03 MPa. Efforts to understand pressures in this case by pushing on the button on the membrane with a pencil will be meaningless -- like pressing on a tyre with a pencil to test tyre pressure (even at only 40psi or 0.28 Mpa).
"Items 'on the shelf' for future work" ....
As this work progresses, more bushes will be replaced and this will contribute to further improvement in ride quality.
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Thank you so much for your incredibly thorough reply!!! You, and the others @suprarx7nut @PADDO @2001LC and @uHu and others have helped so much in my learnings of AHC these past few years. I never wrenched on a car 5 years ago and now I do about 90-95% of all the work myself! My little girls and boy even watch and love it and love all the new tools we’ve acquired.
SPRINGS
With rear loaded pressure at 6.9 I did go back and search the posts regarding the order of stiffness for rear springs options that @uHu @PADDO and @suprarx7nut discussed over the years. That helps a lot if I decide to go route of changing my 27 year old and 299k mile springs. I think I’d have to then lean towards king spring since that’s next in line unless I do just spacers which could help since I’m not too high yet. I was misinformed like many others thinking LC non ahc would be less stiffer than king spring but now know they are stiffer. As you stated perhaps going with ahc lx ones may again not really give much difference. King spring I’d have to then possibly add more weight to this stock car or just deal with the stiffness at times when unloaded. As kids get older and off set the weight of their car seats (three kids weigh 100 lbs total and car seats about 114 lbs total, I’m 185 lbs, wife 115 lbs.) I’ll maybe switch them then. For now I may just enjoy it as is or do the spacers. And maybe another bleed and adding on new oem rear control arms and pan hard bar and sway bar links I already have on shelf may make slight difference and bring rear down a bit too. Or maybe when I put on my new rear ahc shocks and rear ahc lines maybe that may dial it in more also. All parts I already have so I may try all that first before spending on springs.
I also may just not carry as many tools in the car and lessen the load by 50 lbs for now. But 27 year old springs have done their job and definitely need help or replacement. I may do the air bag route. Going to research some more. I just know that for next couple of years or so I do not want to add heavy weight to the car in terms of mods. Vehicle is so tuned I actually get respectful gas mileage also (checked three ways) 19-20 mpg on highway depending on which octane I use. 91 or 93 from shell here. My year it was recommended to use premium and I believe it has helped with keeping cats and Evap canister still going. Anyway going off on a tangent but for now for our needs it’s good stock and still takes us easily into some rugged terrain for camping. Will mod up more in a couple of years and I think king springs and possibly beefier torsion bars as you suggested will definitely help then if I don’t do them sooner. For now enjoy the Lexus not so stiff ride front and back.
Question about your picture you posted. I believe you have perhaps an incorrect figure for rear ih8mud ahc height via tape measure in your picture you posted? As you have 19.75” for front and also same 19.75” for rear. Is that correct or a typo? I’ve always read you want a bit of a rake and using @suprarx7nut cheat sheet I thought rear you want ideally closer to mid 20 inches. Of course we are discussing stock ones here and I believe he is too. Just wanted to ask if that was a typo? I see even on your beautiful one that you’re passed onto your son it has a decent but not a lot of rake. I have about 1 inch front to back. Fronts at 19.5-19.6 inches and rear both at about 20.5 inches.
Very low rear pressures readings when temperature sensor off (and solution in update below)
I went back and saw others also like @MarkTR on this forum had had same odd 2.6 or 2.9 rear pressure ratings at certain times when temperature sensor was off. I definitely did too as mentioned to you the other day in above post. So odd. But yes at times it came up very similar to when temperature sensor was on (6.6-6.9 loaded vs unloaded rear pressure). I’d say it was because I sometimes waited 60 seconds as mentioned by others before recording the pressures but it wasn’t always that. Sometimes it was super low even after a minute and sometimes within 30 seconds it was 6.6-6.9. Just odd why with it off it would give such low pressures and just stay there. But alas it wasn’t always the case.
UPDATE - this is a tech stream issue I believe. First time I do with temp sensor off and you get proper reading. Second and other times you won’t. You need to shut off tech stream. Restart. And then do again and first time with sensor off I will get proper reading again. All other times it shows rear pressure as 2.6.
Anyway after new bleeding and slight torsion bar adjustment, still at 6.9 pressure for rear with or without temp sensor off when loaded. If i do without load and full tank only per FSM, then I am at around 6.4-6.5 which is just within the FSM 5.6 - 6.7.
ANOTHER BLEED
Funny you should mention maybe for me to do another bleed of fluid. I went two days ago and bought another can prior to reading your post. Now I think I may have had bubbles/ frothy mix at first come out from ahc accumulator because I was doing first @PADDO less fluid loss method when changing globes.
Post in thread 'replacing AHC globes/accumulators'
replacing AHC globes/accumulators - https://forum.ih8mud.com/threads/replacing-ahc-globes-accumulators.716383/post-11432901
Jacking up front. Bleed front then replace each globe. Then onto rear after jacking. In that time when I have each globe off and am trying to get on new one I probably am introducing air in, correct?
All four sides had no air come out in initial less bleed method. His last step was to go and try ahc accumulator also if one wants to, it’s then when I had some come out bubbly and white but that’s after new fluid goes in in reservoir. That led me to then all of a sudden change method to @PADDO main full bleed method and so I bled and bled and that’s how I ended up at just right at minimum line of new fluid when all done. And as I like to be a perfectionist lol, I was like I am going to get another can, either just add more to get to max and slightly above max line, because just at minimum doesn’t give me much room in case something happens and I go to high and I’ve lost fluid some how and boom it run dry, and also because I figured another can of bleeding can’t hurt. So tonight I’ll just bleed with this new can. The other night when I went to ahc accumulator a second time I never got bubbles or frothy look like the first time. All just pink and no bubbles. And initial bleed fluid also settled into all one color, darker but not black black or milk shaky because I had added this fluid in two years ago. So I don’t think any issue in there but can’t hurt to just bleed again and this time not over due it and have fluid above max line a bit. Going to do in a little bit tonight.
UPDATE Second Bleed: bled again and all went well. Pinkish fluid (that I put in few days ago) came out as pinkish with no bubbles. From all 5 bleed points. Did @PADDO 1 can method. So probably didn’t need to but I’m glad I did and plus now I have a level bit higher than max compared to before where it was just slightly above minimum. Still getting 14 tick marks on new globes test. Will refresh again within the next year anyway when I put on new AHC rear shocks and lines. Even though front lines and shocks are still good, may just refresh them at same time. Don't cost a lot from Impex. And after that will flush every 2-3 years as I have been as this is so easy to do and I agree with your advice to do quicker than the 5 year 60k mile recommended mark. $70 CAD every 2-3 years and doing it myself is a cheap price to pay to keep this going.
Longevity of 27 year old parts
I like you was shocked that my factory globes were still in tact after so long and everything was still fairly smooth. This spent 17 years in Maryland salt belt but garage kept and rust proofed each year then 6 years in Florida and then now last 4 years up here in Toronto Canada where I continue to rust proof it each year and maintain the pressures and the beautiful ahc system. Drive it in the winter and it’s more fun and at times more smoother than my much newer Lexus RX350. As mentioned only rust is on rear ahc lines in the last 4-6 inches of them and the bracket. No where else on car.
The front lower and upper control arms and sway bar links etc I changed earlier this year at 295k miles, I only did because one lower control arms ball joint was finally loose! All others even when taken off were pretty solid. Toyota Parts were so cheap from impex japan (700 usd for all four control arms and hardware) that I figured this old baby deserved a full refresh. And as stated have entire rear oem control arms set for upper and lower and pan hard bar and sway bar links and bushings all on the shelf ready to switch too when I have some time.
Here are some pictures of my old 1999 LX with 299k miles/ 481,000 km beauty and the 12/1998 manufactured globes I took off which were still intact and giving about 8 on the reservoir globe test. Front windshield had a tint from previous owner, I have since removed it. Also it had about 7 bleeds done over 27 years per Lexus records and I think that also helped it. And lots of highway miles. No off roading, yet. Camping etc but nothing heavy duty, yet. Perhaps that helped its longevity too.
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And here are the dates off old original globes @IndroCruise ahc fluid that dripped on outside made it a bit less clear but still visible. 27 years old 299k miles. Great reliability and who knows maybe still had another year or two in them since I was still at 8 tick marks and none were busted membrane wise.
IndroCruise
SILVER Star
Great report and great plan in Post #289 and Post#290!!
Answer to Question: Apologies offered -- there was a typo in my Post #288, now fixed in a Late Edit to that Post.
Also included in the Late Edit to Post #288 is a link for general interest highlighting how air in hydraulic fluid not only diminishes hydraulic performance due to spongey effects and cavitation damage at pump parts and valve orifices, but also degrades the fluid itself through fluid breakdown, formation of sludge etc. These effects generally highlight the importance of 'hydraulic hygiene' and the reason for regular AHC Fluid change-out with Toyota/Lexus Part Number 08886-01805 per Owners Manual not less frequently than every 60,000 miles or each 6 years, and whenever major maintenance or component replacements are performed on the AHC/TEMS systems.
So the additional bleeding you have undertaken was wise action.
Answer to Question: Apologies offered -- there was a typo in my Post #288, now fixed in a Late Edit to that Post.
Also included in the Late Edit to Post #288 is a link for general interest highlighting how air in hydraulic fluid not only diminishes hydraulic performance due to spongey effects and cavitation damage at pump parts and valve orifices, but also degrades the fluid itself through fluid breakdown, formation of sludge etc. These effects generally highlight the importance of 'hydraulic hygiene' and the reason for regular AHC Fluid change-out with Toyota/Lexus Part Number 08886-01805 per Owners Manual not less frequently than every 60,000 miles or each 6 years, and whenever major maintenance or component replacements are performed on the AHC/TEMS systems.
So the additional bleeding you have undertaken was wise action.
Thank you so much. Just read the article you linked regarding air and breakdown of hydraulic fluid/ diminishing performance. Makes sense!
For fluid changes I will stick to about 2-3 years to change out fluid as I have done so far. I hit about 5-6k miles per year only so would be definitely within the 60,000 miles interval also. And this year will do again when I change out rear AHC lines and new ahc shocks.
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@IndroCruise sorry to bug ya again. But I had an epiphany!! That I missed a step when I read some of your other posts in other threads today. The step AFTER you fix cross tilt while engine off and ahc off. I never did the then turn on ahc and possible play around with height sensor units to see if can get closer to 19.75”. I think I was always a bit hesitant about doing that. And didn’t realize I’m supposed to have two different kinds of readings. One without the ahc on for just a torsion bar which I have been doing and then one afterwards with what the ahc does.
I remembered then a note from previous owner in his little repair /fuel book he did something to them to adjust front and rear for his towing for the couple years he had it. I think he had lowered the front. SOOOO I did that step. Sensor lift by a bit. Got the heights with ahc to about 19.70” in front. I for now didn’t touch the rear height sensor. Sitting still close to 20.5”
REAR PRESSURE DROP!
Redid pressure check on tech stream and my loaded pressures in rear have now dropped by .4 to .5.
Rear now is 6.4-6.5 in rear (loaded up with full tank and kids car seats but of course no passengers) instead of 6.9 loaded last few days.
And unloaded (with full tank and without three car seats) and tools dropped to 6.0 in rear compared to 6.4 before in above posts. Another .4 there also.
So new Rear pressures:
Loaded 6.4-6.5 rear pressure
Unloaded 6.0 rear pressure
Front pressure went up .2-.3 to now 6.3 and 6.4 unloaded and loaded. Understandable since that’s because of the sensor lift and more pressure on ahc system and so that brings me more into good range for fronts per your and other’s posts and FSM.
EDIT - Will maybe release some turns on both torsion bars later in week and further raise front pressure on AHC system.
Drives even better than the other day when I changed the globes. Happy the rear pressures have dropped more. I was lucky originals were still going well even though I had missed this important step few years ago. Feels really good to fine tune and to finally get it all done properly and to know what the real proper data is. And still at 14 tick marks on the new globes. Thank you for all your great write ups!
I remembered then a note from previous owner in his little repair /fuel book he did something to them to adjust front and rear for his towing for the couple years he had it. I think he had lowered the front. SOOOO I did that step. Sensor lift by a bit. Got the heights with ahc to about 19.70” in front. I for now didn’t touch the rear height sensor. Sitting still close to 20.5”
REAR PRESSURE DROP!
Redid pressure check on tech stream and my loaded pressures in rear have now dropped by .4 to .5.
Rear now is 6.4-6.5 in rear (loaded up with full tank and kids car seats but of course no passengers) instead of 6.9 loaded last few days.
And unloaded (with full tank and without three car seats) and tools dropped to 6.0 in rear compared to 6.4 before in above posts. Another .4 there also.
So new Rear pressures:
Loaded 6.4-6.5 rear pressure
Unloaded 6.0 rear pressure
Front pressure went up .2-.3 to now 6.3 and 6.4 unloaded and loaded. Understandable since that’s because of the sensor lift and more pressure on ahc system and so that brings me more into good range for fronts per your and other’s posts and FSM.
EDIT - Will maybe release some turns on both torsion bars later in week and further raise front pressure on AHC system.
Drives even better than the other day when I changed the globes. Happy the rear pressures have dropped more. I was lucky originals were still going well even though I had missed this important step few years ago. Feels really good to fine tune and to finally get it all done properly and to know what the real proper data is. And still at 14 tick marks on the new globes. Thank you for all your great write ups!
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