1st time owner... ACH advice

mickeywatt Jan 10, 2020

  1. mickeywatt

    mickeywatt New Member I am in mexico

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    I purchased a 2006 4.7L land cruiser with 50,000 kilometers. Previously, owed an 04 and 06 Tundra. I am not real mechanically inclined but would like to lift my truck a little 1-2 inches, add oversized off-road tires and understand the ach is prone to problems.

    Looking for advice on what parts I need to properly delete the ACH. As well as brand suggestions for shocks and all parts to accomplish the task. Also any thoughts on wheel and tire size would be appreciated.


    Thanks
    Michael
     
    Chas likes this.
  2. uHu

    uHu Well-Known Member Supporter I am in norway

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    With the AHC you already have a lift of 1-2 inches, at the press of a button, and it is not prone to give problems unless you mistreat it. E.g. the shocks are more durable than anything else you can get. And at 50 k km, it's like new !!! What you do have to do is to check (and probably replace) are the rear springs (by measuring AHC neutral pressure). They don't last 14 years without sagging considerably, and that would be the same for a non-AHC truck.
    You can increase the diameter of the tyres by 2-3 inches without doing any lift.
     
    Last edited: Jan 11, 2020
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  3. t1pper

    t1pper Well-Known Member I am in uk

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    I have 240K miles without any problems AHC works perfectly.
     
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  4. mickeywatt

    mickeywatt New Member I am in mexico

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    Thanks for the information! I appreciate the feed back !!!
     
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  5. mickeywatt

    mickeywatt New Member I am in mexico

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    Could you describe what I am measuring in neutral position? And what the measurement should be?
    When replacing the rear springs do you have a brand or distributor that you would use?
     
  6. IvanD

    IvanD New Member I am in bulgaria

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    You will never be able to get the comfort of the AHC ride with any aftermarket kits. It adjusts compression and rebound on the fly on the turn of knob and maintains ride height and comfort the same when unloaded/loaded.

    Get yourself a Techstream cable - they are on both eBay and Aliexpress for £10-20-30, depending on the deal.
    With that you can check the AHC system pressures - there is a range, that must be maintained front and rear. For the front you adjust by turning the torsion bars. For the rear - new springs and/or spacers.

    The easiest test to gauge the state of the AHC system is to measure the difference between L and H modes - the so called graduation test. There are lines on the AHC fluid reservoir. Put the car in L, take note of the fluid level, then take it to H and note the level. For a brand new system the difference is 14 lines. Anything less, and the pressurised globes are worn. Those are the "consumables".
    If it's real 50000km (wow!) there is still a loooot of life in them.
     
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  7. IvanD

    IvanD New Member I am in bulgaria

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    You will never be able to get the comfort of the AHC ride with any aftermarket kits. It adjusts compression and rebound on the fly on the turn of knob and maintains ride height and comfort the same when unloaded/loaded.

    Get yourself a Techstream cable - they are on both eBay and Aliexpress for £10-20-30, depending on the deal.
    With that you can check the AHC front and rear system pressures - there is a range, that must be maintained to ensure proper function of the system.

    The easiest test to gauge the state of the AHC is to measure the difference in fluid level when car is in L mode and when in H mode. There are graduations on the fluid reservoir. For new system its 14 lines difference, anything below 7 means that the pressurised globes - the "consumable" of the system are shot. If real 50 000km (wow!) there should be a looooong life left.

    Don't believe the posts on different forums about AHC being this horrendous system that will break down any moment underneath you and leave you with no suspension. It's a robust system that works well, when maintained.
     
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  8. uHu

    uHu Well-Known Member Supporter I am in norway

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    Read the 35 pages in the link below. They cover all possible AHC related questions (with some included links to other threads).
    The reason for the long thread is that dealers generally don't know how the AHC works, and often do more harm than good when trying to service it. It's really not a complicated system, but you have to know how it works. You need TechStream or similar and the FSM for maintaining a 100-series.
    https://forum.ih8mud.com/threads/definitive-list-of-ahc-maintenance-items.604577/
     
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  9. jibberjabber

    jibberjabber Well-Known Member I am in england

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    This also might be worth a read, even though it for a Lexus 470 the AHC is identical to a Land Crusier 100, as the are basically the same vehicle. Happy reading.

    Here is an artical from IH8MUD posted way back in Oct 2013, entilted

    LX AHC Off Road Suitability.

    Credit to TeCKis300

    AHC gets a bad rap from most on these boards. While some of it is deserving, as it's a potentially expensive wear item to maintain and repair, most of the other reasons are largely undeserving as it's a robust and capable system that is meant to increase the capability breadth of the vehicle without compromises. That is, it will do very well for on road manners, yet also provide clearance, articulation, and active dampening when the going gets rough.

    I can't find it at the moment, but Toyota had a diagram that compared the capability of AHC vs non-AHC equipped hundy. It basically showed the AHC vehicle having more capability and on and off road. Now you can't have everything and eat your cake too, as the obvious trade-off is increase cost and complexity. Which brings me to my main point.

    Half of the negativity against the system is due to second hand owners unwilling to cough up to maintain and repair what is ultimately a wear item. Not that it's not durable as there are plenty of anecdotal stories about it lasting over 200k. The other half is due to second hand owners trying to modify the system, or use it outside of its carrying capability, without truly understanding how to modify it to do whatever they are doing. Then they blame any fault on some contrived incapability or unreliability of the system.

    Fact is, it's a tremendously capable system that can allow you to have the best of both on road and off road qualities (unlike an off road oriented suspension which biases the truck). I'll list a few.

    1) By it's very nature of having a large fluid volume, it has more thermal capacity than any remote reservoir setup - great for those washboards.

    2) The suspension is ACTIVE, so it has the ability to automatically dial in the right dampening for any particular wash board and load.

    3) AHC will RTI higher (toyota supported fact) due to its smaller anti-roll bars and active height control.

    4) AHC is constant height, regardless of load within its rated capacity. For example, if you toss in 4 people and gear on a standard non-AHC hundy, you'll already begin at a lower ride height relative to the AHC equipped hundy. Nevermind that the AHC can lift on demand.

    5) AHC can have more lift than a statically lifted (stock non-AHC shocked) hundy on demand. Because the non-AHC truck has to compromise to leave some droop in it's setup. The AHC can go even beyond its on demand high position, when the ECU detects the need.


    Sorry for my long winded reply, but I hate watching the herd mentality (eg. above) bash AHC on these boards , without a substantive reply.
     
  10. IvanD

    IvanD New Member I am in bulgaria

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  11. jibberjabber

    jibberjabber Well-Known Member I am in england

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    :text-goodpost:
    Very, very good and very informative, the AHC system on the 200 series is a little more sophisticated than on the 100 series, but still a good video. Well done on finding it.
     
  12. Philip amos

    Philip amos Member Supporter I am in uk

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    ive have a landcruiser for a year now and have recentlyhad a couple of problems with mine ie burst pipe new strut and a pump.i can honsetly say its notas daunting as it seems and not as expensive to repiar as people say. I built up a supply of parts over the year waiting for the fait full day.burst pipe cost £50 new i tooh it to a hydraulic specialist and they repaired ,strut i bought new £180,full pump and tank £150 used ,but if motor goog you can buy new pump for£150but itmeans a strip down of unit. I i got a used spare so it was a quick change round.So what im saying is a bit of forward planning and all will be ok.
    Maybe if i was doing a lot of heavy off roading then i would of had a different view but i dont.
    Hope this helps
     
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  13. jibberjabber

    jibberjabber Well-Known Member I am in england

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    "Heavy off roading" or not AHC is just as capable of dealing with both, it can be lowerd:thumbdown: for easy access for us 'Old Gits', or raised:thumbup: for the 'Young Studs' to play in the rough tuff stuff, all at the touch of a button.

    I remember the 'good old days' when touching a button got me raised.:text-givemebeer:
     
    Last edited: Jan 18, 2020 at 3:57 PM
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