Why the AHC hate? (1 Viewer)

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SHIfTHEAD

SHIfTHEAD

Joined
Feb 1, 2016
Threads
41
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617
Location
Fort Mill, SC
My LX has 252K miles on it and (knock on wood)the AHC is still functioning as expected. However I know that at some point it will require maintenance. So let's go crazy, let's say I swap all the hydraulic "shocks" at $1000, and all the globes at $1600. These are the primary wear items, right? And let's say that they only last 1/2 as long as the originals did, that's still 8 years or 125K miles, or something like $300/yr in costs. Having the ride I have today, with the ability to add 2 inches when I'm off road is pretty damn sweet. Mind you, I'll never put and ARB bumper on a stock LX, that's what the FJ62 is for, but I'm still left puzzled. A standard suspension setup is like $1500. So is all the hate for the possibility of another grand in parts costs?
 
I don’t really think it’s hate... I think people are just being practical about a 12+ year old hydraulic system. It’s more than just the globes and the hydraulic shocks. There’s the pump, control valve module, etc. With the age comes the possibility of the above mentioned wear. Some of us that use our 100s pretty hard offroad just have more peace of mind by installing a conventional suspension system.

If you are strictly driving street with minimal trail time, keep it. But for me the possibility of having a part fail or springing a leak offroad was just too much. And after seeing my fluid come out nasty even after several swaps, was enough to convince me even further.
 
Trunk Monkey said:
Not everyone has $2,600 to drop on repairs, even if it's infrequent.
Click to expand...
Agreed, but that was what I assumed was a worse case scenario, replacing most of the system. I haven't seen that needed to happen,save for one recent guy whose truck was really crusty anyway.
 
I recently opted to replace my AHC when it started to have issues. It had nothing to do with "hate".

I enjoyed the AHC system in my vehicle for the last 13 years, but:

1) I was ready to start making modifications to my old vehicle, as I don't currently have a FJ62 in the driveway. If you're driving around a mostly stock vehicle, not adding significant weight, and mostly using it around town, maybe refurbishing AHC is right for you.​
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2) I've currently got some back issues that makes doing my own work on the AHC system difficult. I've dealt with Lexus/Toyota dealerships in troubleshooting the air suspension on the GX470/T4R, and was not impressed. I expect that the level of expertise on the more complex AHC hydraulic system would be more of the same.​
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3) I think you've missed a number of components to the system. Lets say 6 months after spending your hypothetical $2600, the AHC pump dies, MSRP on that is only $3545.99 (according to google).​
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4) About the time I was debating what to do, I noticed more posts on "RTH needed for AHC" posts, most of the time while far from home:​
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Historically, I had been kind of amused by some of the postings on 'mud about having a fear of purchasing an AHC vehicle, and the high failure rate, but a 13 year old system failing in the middle of a 12+ hour road trip can add some significant "excitement" to the trip.​
 
DirtDawg said:
I don’t really think it’s hate... I think people are just being practical about a 12+ year old hydraulic system. It’s more than just the globes and the hydraulic shocks. There’s the pump, control valve module, etc. With the age comes the possibility of the above mentioned wear. Some of us that use our 100s pretty hard offroad just have more peace of mind by installing a conventional suspension system.

If you are strictly driving street with minimal trail time, keep it. But for me the possibility of having a part fail or springing a leak offroad was just too much. And after seeing my fluid come out nasty even after several swaps, was enough to convince me even further.
Click to expand...
Yeah, I can totally see that logic. But as my current DD, man I'd hate to lose it. I'm fine with a few hundred a year, on average, to keep it going. Hopefully that doesn't come back to haunt me.

jLB said:
I recently opted to replace my AHC when it started to have issues. It had nothing to do with "hate".

I enjoyed the AHC system in my vehicle for the last 13 years, but:

1) I was ready to start making modifications to my old vehicle, as I don't currently have a FJ62 in the driveway. If you're driving around a mostly stock vehicle, not adding significant weight, and mostly using it around town, maybe refurbishing AHC is right for you.​
​
2) I've currently got some back issues that makes doing my own work on the AHC system difficult. I've dealt with Lexus/Toyota dealerships in troubleshooting the air suspension on the GX470/T4R, and was not impressed. I expect that the level of expertise on the more complex AHC hydraulic system would be more of the same.​
​
3) I think you've missed a number of components to the system. Lets say 6 months after spending your hypothetical $2600, the AHC pump dies, MSRP on that is only $3545.99 (according to google).​
​
4) About the time I was debating what to do, I noticed more posts on "RTH needed for AHC" posts, most of the time while far from home:​
​
​
​
​
​
​
Historically, I had been kind of amused by some of the postings on 'mud about having a fear of purchasing an AHC vehicle, and the high failure rate, but a 13 year old system failing in the middle of a 12+ hour road trip can add some significant "excitement" to the trip.​
Click to expand...
No doubt, in the middle of a trip would suck, bad. And you are right, the motor is another wear item. Looks like they are about 1100 new out there.

So I guess if I could find a standard suspension that was 90% as compliant as AHC I'd probably do it too if I was facing 4grand in costs all at once. But I also have a 5.7 Tundra and I don't like driving it everyday. It rides, well, like a truck.
 
@SHIfTHEAD I'm with ya. I don't get it. AHC is a fantastic feature and failure of the entire system at once must be extremely rare.

Trunk Monkey said:
Not everyone has $2,600 to drop on repairs, even if it's infrequent.
Click to expand...

The part that I find funny though is many people spend 3/4 that when they remove it. They buy brand new shocks, springs, torsion bars, sway bars, links, bushings, etc... all just to end up with a static suspension which often offers less of a lift and a huge detraction in ride quality.

If folks delete AHC and spend $500 on the replacement system with some used components then I get it. That doesn't seem to be what people do, though.

I can understand if folks don't have a good shop nearby and if they can't work on stuff themselves, like @jLB . That makes total sense and I get it. Dealership service departments probably just play invoice BINGO until the problem is fixed or the customer gives up and trades in for something on the lot.

It seems with a techstream setup and some basic diagnostics you could at least guide a shop on what parts to replace, though.
 
AHC is fantastic, and I am an AHC lover, but...

- When you go offroad and switch to high it doesn't quite perform very well. It's designed to perform well in "N" mode. Not like "N" mode is not high enough 95% of the time.
- If you have the smallest amount of rust on the truck, it's likely that you have to cut out the struts when replacing. If you can't undo even one of the 12mm bolts that hold the AHC line to the strut, you're looking at buying a new AHC line on that corner, that adds to the cost. And the rear lines are very hard to replace without taking the body off.
- Actuators (if that's what they're called, the things that the globes screw onto and has the valves inside them that control the damping) can also fail and are not cheap. Once again, with rust on the truck these are not easy to replace & might crack/bend the lines attached to it while undoing. It's not trivial/easy to diagnose these, so you might be pulling your hair/throwing money away in the process.
- The height sensors also wear, and they are not very cheap for what they are either. Actually if these are not spot on, the system will randomly behave weird and you'll pull your hair to diagnose the trouble.
- Then there is the main valve assy, can also fail.
- With the age it's unknown when the pump and/or the accumulator is going to fail. Imagine replacing all the parts above for serious money, thinking that now you finally nailed it, and all is cool, then half a year later your pump fails. You replace that and then your accumulator fails half a year later. Maybe you replace that and then your engine/transmission/diff, etc. fails.. You then won't get rid of the truck, because you've just pumped a ton of money into it via the AHC (which didn't raise the value of it), but have to replace the non-suspension component to keep the truck alive, also a ton of money which doesn't add to the value.. See the spiral here?

So I see it as a never ending story, unless you replace all components, which is near $6-7k at least, probably more if you can't DIY it. If you think of it being half of (or maybe more) the price of the truck, while not adding anything to it's resale value, it's not a great investment. One has to be realistic and understand that only few of these trucks will outlive the second iteration of AHC components on it. But for the same money you could swap out a conventional suspension every 2-3 years, and still pull 10-15 years out of it, while always having a brand new suspension under your car & if another expenive component lets go, then it doesn't hurt as much to quit.
It's true that you give up some (okay, a lot of) comfort with a conventional suspension depending on your use-case, but you also gain durability, peace of mind, and a lot of money, which you can spend on trips, or even other gadgets (tires, wheels, bumpers, roofrack, tent, offroad equipment, wife, etc.).
 
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Pretty simple:
The AHC adds another layer of technology that might fail. Even driving a forrest road might kill the ahc if a piece of a fallen down branch jumps up and cuts a sensor cable, or bends a sensor linkage. For a utilitarian vehicle, most people wants it as simple and reliable as possible. Overload is a problem (typical expedition set up) unless you modify the system for your intended use.

Otoh, the ahc shocks last for ever, nearly. Normally it's only rust killing them.
What you do have to change regularly are:
Rear springs. Just the same as with a stndrd susp.
Spheres, but not often, and far from as often as shocks on a stndrd suspension. Also depends on how well you keep the neutral pressure at the right range.
Sensors wear out. They last approx as long as the spheres if not subjected to heavily salted roads, at least 10 years.

The biggest problem with the ahc is that dealers and other repair shops don't understand how it works or how to diagnose it. The dtc (codes) you get from that system are really not very helpful for many of the problems, and reading the manual seems to be a problem for most people.
 
I don't see why we have to discuss this every 4 months.

IMO people don't "hate" on it... But the guys who like it are fairly religious about their belief in the systems' performance.

Either way, it's just another viable option for a suspension in these vehicles. Which is great.
 
All this talk of expensive replacement parts... you guys know you can buy used parts, right? I was one of those “RTH AHC stuck in LO flashing” guys and solved my problem for $400 including fluid. That was for that $4k AHC pump.

Guess I should keep it to myself though, because I’m probably keeping my AHC running using parts the haters are pulling off!
 
My 07 kept going into Low on the highway and on the trails because we had too much cargo loaded on it. And at some point the fluid just disappeared somewhere in the middle of highway driving out in the country with no visible leaks. Luckily my brother who works in Lexus service was smart enough to bring a few cans of AHC fluid with us on the trip so that fixed that issue quickly. Truck drove like complete crap with the low fluid level. Just too unpredictable. 07 with 120k miles and flawless maintenance history and clean fluid that was changed several times prior. Street driving with no cargo it still performed flawlessly. All damping setting worked great and raising and lowering always performed amazing when daily driving. Got conventional suspension now just for peace of mind.
 
AHC is a solution that was looking for a problem. It gives the land cruiser an identity crisis.

If the rig is supposed to be a comfortable passenger vehicle, then it has too much unsprung weight to ever really compare to a sedan.

If it's supposed to be a dead nuts reliable SUV, then hydropneumatic suspension isn't that.

If you want it to be an off-road beast then it doesn't have the travel necessary to succeed. Raising height is great except you have no downtravel now. Fail.

Inevitably people will be like 'but now I can do all 3!!!' - ok sure buddy. I bet you have an undying affection for cargo shorts and Leatherman multi-tools too.
 
nukegoat said:
. I bet you have an undying affection for cargo shorts and Leatherman multi-tools too.
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No one's gotten a beej in cargo shorts since 'Nam. Everyone knows that.


If I were only going to use my 100 for street and highway use, I'd keep the AHC. But then, like nukegoat says, it's not being used as a Land Cruiser at that point.
 
nukegoat said:
If it's supposed to be a dead nuts reliable SUV, then hydropneumatic suspension isn't that.

If you want it to be an off-road beast then it doesn't have the travel necessary to succeed. Raising height is great except you have no downtravel now. Fail.
Click to expand...

That’s just it! It IS a dead nuts reliable system. It was developed for the Land Cruiser by Toyota, who knows what the LC is, what is expected of it... and who knows a thing or two about reliability. Which is precisely why there are so many reports on this site about AHC working flawlessly after 20 years and 250k miles. That is absolutely UNHEARD of in an adjustable suspension system.

And dead nuts reliable means what? Never fails ever ever? That doesn’t exist. The car is full of things that can fail and strand you and ruin a trip. Every car is. Dead nuts reliable compared to any other adjustable suspension system? Hell yes! Dead nuts reliable compared to a conventional setup? Even conventional struts rarely hold up for 200k+ miles. Cheap to replace as a conventional setup? Not if you’re replacing the entire system—but when and why would you ever need to do that? And you can service the system with used take-offs, which you cannot do with a conventional setup. When those fail, you replace them with new units. I will give you that conventional is simpler, but if simplicity is everything, I wonder why you’ve got such a new vehicle full of modern systems anyway, instead of an 80 or older.

And speaking of 80, with regards to downtravel—you’re already sacrificing downtravel in the 100 with the IFS.

But the benefits outweigh the drawbacks for most. I off-road my LX plenty, more than a lot of folks with beefier machines. I can keep up with some beasts. TBH, most of the built rigs are overkill for the kind of off-roading most of us are doing. By the way, a *stock* Land Cruiser is overkill for the kind of off-roading most of us are doing! But that’s part of the appeal.

But most of us also drive on the road, a fair bit. And, appearances aside, I would much rather drive around on road with a system that is lower at high-speed. Rollover risk is greatly reduced with AHC, not to mention the many systems that are integrated into it— anti-roll, anti-squat, etc. (Read more on this here: https://st.club-lexus.ru/attach/u/6b15e9be.pdf )

Tangent aside, to suggest that AHC relegates the 100 for on-road use only is kind of insane.

PS— I’ve said it before, I’ll repeat it here. Our resident AHC expert, PADDO, mentioned previously he has a history in military engineering (something along those lines). He reports Toyota’s AHC system as being “military-grade” robust. Let me also remind you that hydropneumatic systems are used in tanks. Tanks. You’re welcome.
 
The bottom line— Do whatever you want. I get the reasons for switching to conventional. And presumably, that better suits how you intend to use the truck. But there’s no need to denigrate the AHC, or folks that opt to keep it. It’s enormously functional, enormously robust, and enormously awesome. Just like everything else Land Cruiser. Now, stop hating and wheel your damn rig!
 
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