Definitive list of AHC maintenance items

[RaikoJ]

I will try to find someone, who can help me with measuring. We tried with mechanic team find the noise maker, but we didn´t fint it. To me seems, that rear shocks are making that?! My problem is like that: every time, when i start to accelerate from stop, then comes from rear some kinda bounce, sometimes between fisrt and second gear, sometimes when the gearbox is changing gear, sometimes right when i will start to accelerate. And to me seems, that car rear suspension is pretty stiff.

 

[RaikoJ]

I used wrong word, sry about that. English isn´t my native language. There is no bounce at all, i wanted to say "punch or blow or something" Weird punch in never knows time after acceleration. But no bounching, just a bit stiff or hard rear suspension and annoying/disturbing punches.

 

[RaikoJ]

Today i had chance to deal with my car suspension. result after 1 hour of adjusting TB-s and measuring was successful, front pressure was 6.3MPa´s and rear 6.8MPa´s, from floor to front fender 855mm and rear also 855mm. The car itself handling much better and front part is stiffer and better on braking. No more that loud punches from rear axle, but some small punches is still there. I think, i will buy new rear coil springs and then adjusting again the suspension...must be good.

 

[SAMTHEMAN]

Don't overthink the issue. Those height differences are small. The ahc system will not do any correction until the "error" is over a certain limit, it doesn't bother with a few small millimeters.
Otoh, you might have a bit looseness in the linkages, evt also combined with a high friction in the sensor shaft, but with the small differences you see, there is no reason to suspect it. Another issue that comes into play, is worn carbon traces in the sensors, which give unreliable readings, and can also give the ahc ecu an idea of you driving on very corrugated roads.
But the readings you get seem to be normal, you will get a variation of a few mm for each time you test (Not so much if you just stand still all the time). And, the difference between going from Hi to N and going from Lo to N can be much bigger than that.

For the left/right balance, you adjust the torsion bars, as described in several threads here. Althogh your L/R diff is very small.

Dear uHu/PADDO
I have replaced the 4 accumulators lately
the ride was very comfortable after that

I am desperately seeking for the original ride height of the vehicle as I got it at 106,000 KM
do you have any guidance to me on the ride height of 2004 /6 land cruiser with 17 inch alloys
I like to know such as from fender lip to rim bottom lip or the rim center

I am looking at the comfort and the handling on high way rather than off roading so I think the stock height s the best height !!!
further i see my shock absorb er bottom bush are deformed as teh center steel bush has been pushed downwards off center due to holding loads for 13 years,, it does not seem to loosely moving but may have a play when the tires are om vibrating roads..

I am about to replace them too..

Pleas help me on the vehicle stock heights (factory height setings)

 

[sawdustmkr]

I just wanted to thank everyone here for the extremely helpful information on this site. Recently my '03 LX dropped to the L setting and would not pump back up. I read thru several of the AHC threads including this one as well as loads of great information provided by @uHu & @PADDO. This gave me the confidence to attempt the fix myself and avoid dropping it off (along with a bundle of cash) at Lexus. I narrowed it down to a DTC62 error code and ended up replacing the pump assembly yesterday with one purchased from a salvage yard. Was completely surprised that the entire project only took a few hours start to finish and $225 out of my pocket. Everything worked out perfect and I am riding in comfort once again! Thanks!!!

 

[SAMTHEMAN]

I also want to add to your comment.. I was also desperate some time back after buying a 106,000lm run land cruiser. I was given repair estimates (more than 10,000USD ) on fixing things by dealers,
And I am now able to get almost every thing related to my cruiser done by me with the help of this forum and the remarkable help from @uHu & @PADDO.

Thanks to all of you and @ uHu & @PADDO for helping me
Now I have helped a many others too free of any charge to get there Cruisers and Lexus right..

 

[ChuckB]

I’m back in the game! After a long hiatus, I managed through sheer luck to get TechStream up and running on an HP Stream 7 tablet. Story here:

Help Can't get Techstream to function

Here is my first screenshot on not necessarily flat ground. As I suspected my rear pressure is high. New springs should be in the mail tomorrow.

What’s the consensus on needing the 30mm spacers as well?

I’m debating ordering the spacers to have on hand just in case, but hoping new springs will be sufficient.

(edit) I went back through the thread again and @PADDO suggested adding spacers and new coils to get on the lower side of the operating envelope for rear pressure. I'll probably go that route.

 

[PabloCruise]

Glad you got your TechStream working!

 

[ChuckB]

Question regarding Coil Spacers and OEM rubber isolators. I haven't been able to find a "definitive" answer from searching.

I'm getting ready to install the Slee 1" spacer on top of new OEM AHC rear springs. What's the group consensus on installing the OEM spring isolator on top of the spring spacer? It seems like it will fit. I read that few people have chosen to leave them off. I'm just wondering if there are any negative aspects I'm not considering?

 

[rroverbkk]

I just wanted to thank everyone here for the extremely helpful information on this site. Recently my '03 LX dropped to the L setting and would not pump back up. I read thru several of the AHC threads including this one as well as loads of great information provided by @uHu & @PADDO. This gave me the confidence to attempt the fix myself and avoid dropping it off (along with a bundle of cash) at Lexus. I narrowed it down to a DTC62 error code and ended up replacing the pump assembly yesterday with one purchased from a salvage yard. Was completely surprised that the entire project only took a few hours start to finish and $225 out of my pocket. Everything worked out perfect and I am riding in comfort once again! Thanks!!!

Sawdustmkr,

Any particular way you eliminated the height sensors as a culprit?

What is the pump assembly part number you mentioned?

 

[PADDO]

Here’s a copy of AHC DTC problems & symptoms - should help you fall down the right diagnostic rabbit hole

 

[JPS]

Regarding your question about bleeding, see the thread that the yuji the OP linked to: AHC Fluid Change How To -- Need Input

You asked "Some say clear the fluid from accumulator completely, other say it will draw air into the system and things like that."

I believe the only way you could draw air into the system would be to drain so much fluid at one time that the reservoir runs empty. Even in that case, there is a procedure to fix the issue. Also, if you were afraid of that happening (like you just replaced all globes and shocks?), you could have someone standing at the reservoir refilling as the fluid level goes down...

If you are conservative in your bleeding approach and you only bleed (and refill as you go) one accumulator at a time while in Low, you should be fine. There were three important points there:
1) one accumulator at a time (to be conservative don't shortcut and do more than one accumulator at once)
2) refill as you go - in other words make sure when you start you're at full reservoir capacity (actually fill up to the top of the reservoir if you want to be safe), then you go into Low and bleed as much as will come out from a single accumulator, then raise to N height and the fluid level will come down, then refill back up etc... Also - if your goal is to COMPLETELY replace fluid (and not just to bleed air), you may want to empty the reservoir - that's fine, but refill it with fresh fluid prior to raising the system or you will have an empty reservoir and draw air into the pump...
3) while in Low - in other words, if you are in Normal or High height and bleed, you may bleed more than the reservoir can hold which means unless your standing there filling as the level goes down you may draw in air. So be sure to go into Low first.

Following those tips I don't think you have to worry about drawing air into the system.

Hi Againsin,

I have bled my LX, but never changed the globes.

When you bleed an actuator until the suspension bottoms out, and replace the cap at the bleeder screw, has this let out enough pressure to then remove a globe safely?

Also, will hydraulic fluid pour out of the globe or is the suspension being "bottomed out" prevent the loss of hydraulic fluid?,...due to all pressure being released.

I am looking at replacing the globes soon and want to do a total flush this time, I plan to put an extra can through the system in case there are any contaminants, but I am hesitant about getting air in the system. If air does get in, and system is refilled, is the pump able to catch prime and refill the system allowing air to be bled out?

Thanks!

 

[kingkonger708]

I have a full OEM AHC system and suspension for sale on a low miles 2006 Land Cruiser in perfect working condition if you are interested. I installed a lift and the existing suspension was in such good condition that I had it professionally removed.

 

[PabloCruise]

I have a full OEM AHC system and suspension for sale on a low miles 2006 Land Cruiser in perfect working condition if you are interested. I installed a lift and the existing suspension was in such good condition that I had it professionally removed.

That is great.

Your best bet would be to post a thread in the Classifieds stating where you would be shipping from, and price.

Classified section for parts: Classifieds - Parts

There is a subsection for Suspension parts (I see a guy selling his AHC system in there): Classifieds - Axle/Suspension

 

[Agent T]

I need some help with my 1999 LX. Let's say the torsion bars where disconnected and all the height sensors had also been removed...so there are no starting index or reference points available. If that was the situation, how would I go about setting up the AHC suspension? There is much more to this story, but is the short version.

 

[Agent T]

Thank you!

 

[PabloCruise]

I need some help with my 1999 LX. Let's say the torsion bars where disconnected and all the height sensors had also been removed...so there are no starting index or reference points available. If that was the situation, how would I go about setting up the AHC suspension? There is much more to this story, but is the short version.

Sounds like a story!
Do you have the original components to re-install?

 

[Agent T]

Everything is installed, but way out of adjustment. I think the indexing on the left torsion bar is off and the front height sensors were disconnected. So I'm trying to set up with no baseline and I feel like the AHC is fighting itself. So, if I were to approach the project as if the height sensors and torsion bars were uninstalled...what's the set up procedure? Thanks

 

[PADDO]

Everything is installed, but way out of adjustment. I think the indexing on the left torsion bar is off and the front height sensors were disconnected. So I'm trying to set up with no baseline and I feel like the AHC is fighting itself. So, if I were to approach the project as if the height sensors and torsion bars were uninstalled...what's the set up procedure? Thanks

The set up procedure is quite straightforward and has been covered so many times in this, and other, threads. Your baseline points for the height settings are the ground to suspension reference point measurements [which can safely be extrapolated out to approximately 19.5 inches F and 20.5 inches R as measured from hub center to fender bottom] that return 0 +/- 0.2 inch at N height as per Techstream data list feedback and the baseline for the torsion bars is being within the pressure tolerances at this height, ideally 6.9MPa. Disconnected height sensors isn’t relevant as long as they are connected and functional now. As long as the torsion bars have sufficient adjustment left on their threads to enable cross level and correct pressure setting then that will allow you to return the system to something very close to where it should be. Just follow the FSM process of setting up heights and neutral pressures, these .pdf procedures have been posted previously.

 

[deanfun]

As a quick contribution, I tackled some minor AHC adjustment today on my '07 LX. I replaced the fluid and rear springs in 2014. Since then I've put about 80k kms on the truck. Today I measured...

front: 7.6
rear: 7.2

I measured ground-to-fender through the hub and saw the drivers side was 1/4" lower than the passenger. I did 3.5 turns CW on the driver side and 2.5 turns CW on the passenger side torsion bars. Then I installed 10mm spring spacers / trim packers in the rear. New pressures...

front: 6.9
rear: 7.2

I'm disappointed that 10mm doesn't seem to have affected the rear pressures at all, especially considering the springs are only four years old. I supposed the next step will be thicker trim packers.