Air suspension question

[Amazo]

will report back here shortly after the conversion (15-8-24) with a totally honest opinion on whether I regret this decision or not. I've nothing to hide. If it turns out to be a poor choice I will say so. I'm not one for fibbing

My apologies for saying air suspension when it's not. It must be annoying for some.

As promised I am back here to update regarding my conversion from AHC to conventional springs and shocks.

To be honest I was anticipating some noticeable downsides to the conversion, but hand on heart, there are no downsides at all so far. At low speeds the new suspension handles the bumps and pot holes better than the AHC. At speed on the open road the car is quieter and equally as smooth as the AHC. On corners the roll is less and the handling is better. So far no downsides after two days of driving. I am very pleased with the new set up, and have zero fears of waking up to sunken suspension again, and no fears of AHC failure whilst driving. A total win.

No AHC pipes have been cut, just disconnected and tied up. The spheres are still in place, and the pump is disconnected. I still have the rams and springs, so if a future owner decided on reconversion, I have everything they need except that one ram is totally shot.

 

[kevgentile]

As promised I am back here to update regarding my conversion from AHC to conventional springs and shocks.

To be honest I was anticipating some noticeable downsides to the conversion, but hand on heart, there are no downsides at all so far. At low speeds the new suspension handles the bumps and pot holes better than the AHC. At speed on the open road the car is quieter and equally as smooth as the AHC. On corners the roll is less and the handling is better. So far no downsides after two days of driving. I am very pleased with the new set up, and have zero fears of waking up to sunken suspension again, and no fears of AHC failure whilst driving. A total win.

No AHC pipes have been cut, just disconnected and tied up. The spheres are still in place, and the pump is disconnected. I still have the rams and springs, so if a future owner decided on reconversion, I have everything they need except that one ram is totally shot.

Happy to hear you got what you wanted in the end. But, It's an unfair comparison when you never had a properly functioning AHC system.
Either way, enjoy!

 

[BullElk]

I also just converted my overlander '06 LX to OEM torsion bars, OEM springs with 25mm spacers. What I have noticed is very smooth riding on a smooth road, (not surprising) but not as smooth with bump recovery as with proper AHC. Sometimes the rear hits too stinkin hard with obvious no hydraulic pressure assistance. And it will be necessary to use airlift 1000 airbags in the rear to hold up the few hundred #s of camping gear. Four new tires 33"and steel deer basket in the rear sunk it down pretty good.

 

[Amazo]

Happy to hear you got what you wanted in the end. But, It's an unfair comparison when you never had a properly functioning AHC system.
Either way, enjoy!

As far as I'm aware it was properly functioning for 7 years until it went wrong 6 weeks ago, but maybe it was dodgy all that time? Who knows? I've never driven another AHC to compare.

 

[Amazo]

I also just converted my overlander '06 LX to OEM torsion bars, OEM springs with 25mm spacers. What I have noticed is very smooth riding on a smooth road, (not surprising) but not as smooth with bump recovery as with proper AHC. Sometimes the rear hits too stinkin hard with obvious no hydraulic pressure assistance. And it will be necessary to use airlift 1000 airbags in the rear to hold up the few hundred #s of camping gear. Four new tires 33"and steel deer basket in the rear sunk it down pretty good.

If I was carrying heavy loads like you, I may have considered fixing the AHC, but I'm yet to carry a heavy load in my 7 years of ownership. I tow a trailer occasionally weighing approximately 1 ton, and I always found that to be a jiggly experience, but that might be down to the balance of the trailer, although it always towed smoothly with my 3.1td Trooper. So maybe there was always something wrong with the AHC

 

[uHu]

Sorry I didn't see this thread until now, and happy that you are happy with your suspension now.

If your ahc was no good on sharp bumps in low speed, it means that it didn't work right. Probably a blown sphere/globe or two (always use OEM), or just pressures out of spec. E.g. on washboards, or a road full of pot holes, I just turn the ahc adjustment to the left (comfy setting) and the washboard disappears. Insanely smooth ride.

The fact that your mechanic didn't immediately check the neutral pressures, height, and fluid level difference between Low and High, is a proof that he doesn't understand the ahc system at all. All it takes is to read the FSM and spend a day on the thread linked to in post 4 here, and you can see how simple and easy the ahc system is. Still, more than 95 % of t0yota mechanics have no clue about how it works. If you know what your doing, it's normally cheaper to fix ahc, than to convert to non-ahc. In my experience, all Land Cruiser coil springs (ahc or not) have to be changed every 5 years or so, because they sag. (for ahc, that means increased neutral pressure). On a non ahc car, you have to change 2 coils and 4 shocks every few years. On an ahc car you also have to change coils, and then, after many years, also globes and height sensors. The rest lasts for ages.

Anyhow, the crime is done, and there are benefits to a simpler suspension setup. Happy cruising.


PS, re Air Suspension: ( @J1000 )
First, the gas we call air is 88 % nitrogen, so for suspension purposes, nitrogen = air.
Air suspension can either be with bellows (or similar) attached directly to the axles, or via hydraulic fluid to a gas filled globe, like Citroën did maaany years ago. The benefits to the hydraulics inbetween is that the suspension becomes adjustable, both height and damping. This t0yota version is a hybrid, where the air suspension is assisted by steel springs (straight, adjustable torsion bars in the front, and coiled up torsion bars (also called coil springs) in the rear). Still we have the benefits of a fully adjustable suspension system.
Most suspension systems have hydraulic fluid for damping, in the shock absorbers. Either only inside the shocks, or with an external reservoir. This ahc system in addition has external, adjustable valving, bringing the damping to a higher level of performance, where many sensors and parameters adjust the damping on the fly. Also, the valve body has no problem with overheating, like some performance damping shocks have.
So, since all suspension systems are somewhat hydraulic, we can not call the ahc a hydraulic suspension system.
What do we call it then? I don't know - Maybe a hybrid air suspension system? Or just AHC - TEMS.

 

[Amazo]

Sorry I didn't see this thread until now, and happy that you are happy with your suspension now.

If your ahc was no good on sharp bumps in low speed, it means that it didn't work right. Probably a blown sphere/globe or two (always use OEM), or just pressures out of spec. E.g. on washboards, or a road full of pot holes, I just turn the ahc adjustment to the left (comfy setting) and the washboard disappears. Insanely smooth ride.

It was no good on sharp bumps. I questioned this on TLOC 6 or 7 years ago, and found several people with the same problem but no answers, so I tried a couple of things.

Firstly I had the spheres changed, which made no difference at all.

Someone had suggested the rear springs might be saggy, so I changed them and no difference at all. They were the correct purple band springs.

All the time the pressures were good., and the levels in the reservoir were also good.

So I've lived with it for several years, and once the rear ram popped, this was my cue to change things.

I think it's quite clear that mine never worked properly, as the ride could never be described as "insanely smooth". It was very good, but not that good.

 

[uHu]

OK. I understand that you did a bit deeper research than what I thought after reading this thread only. It's good that it works well now. Keep it well polished, lubed and rust proofed, and you'll be cruisin' into eternity. Thank you for sharing and for taking care of a piece of LC history.

PS: I saw a beautiful, well kept Ford model A today, so in 50 years time, your cruiser will be even rarer than an A today.

 

[Amazo]

OK. I understand that you did a bit deeper research than what I thought after reading this thread only. It's good that it works well now. Keep it well polished, lubed and rust proofed, and you'll be cruisin' into eternity. Thank you for sharing and for taking care of a piece of LC history.

PS: I saw a beautiful, well kept Ford model A today, so in 50 years time, your cruiser will be even rarer than an A today.

"Cruising into eternity"......I like the sound of that. Chances are the cruiser will outlast me.

And I do try to keep her shiny. Good paint for 20 years old.

Lived in Marbella for the first 13 winters of it's life, so avoided the salty UK roads until I got hold of it.

 

[baltistyle]

Sorry I didn't see this thread until now, and happy that you are happy with your suspension now.

If your ahc was no good on sharp bumps in low speed, it means that it didn't work right. Probably a blown sphere/globe or two (always use OEM), or just pressures out of spec. E.g. on washboards, or a road full of pot holes, I just turn the ahc adjustment to the left (comfy setting) and the washboard disappears. Insanely smooth ride.

The fact that your mechanic didn't immediately check the neutral pressures, height, and fluid level difference between Low and High, is a proof that he doesn't understand the ahc system at all. All it takes is to read the FSM and spend a day on the thread linked to in post 4 here, and you can see how simple and easy the ahc system is. Still, more than 95 % of t0yota mechanics have no clue about how it works. If you know what your doing, it's normally cheaper to fix ahc, than to convert to non-ahc. In my experience, all Land Cruiser coil springs (ahc or not) have to be changed every 5 years or so, because they sag. (for ahc, that means increased neutral pressure). On a non ahc car, you have to change 2 coils and 4 shocks every few years. On an ahc car you also have to change coils, and then, after many years, also globes and height sensors. The rest lasts for ages.

Anyhow, the crime is done, and there are benefits to a simpler suspension setup. Happy cruising.


PS, re Air Suspension: ( @J1000 )
First, the gas we call air is 88 % nitrogen, so for suspension purposes, nitrogen = air.
Air suspension can either be with bellows (or similar) attached directly to the axles, or via hydraulic fluid to a gas filled globe, like Citroën did maaany years ago. The benefits to the hydraulics inbetween is that the suspension becomes adjustable, both height and damping. This t0yota version is a hybrid, where the air suspension is assisted by steel springs (straight, adjustable torsion bars in the front, and coiled up torsion bars (also called coil springs) in the rear). Still we have the benefits of a fully adjustable suspension system.
Most suspension systems have hydraulic fluid for damping, in the shock absorbers. Either only inside the shocks, or with an external reservoir. This ahc system in addition has external, adjustable valving, bringing the damping to a higher level of performance, where many sensors and parameters adjust the damping on the fly. Also, the valve body has no problem with overheating, like some performance damping shocks have.
So, since all suspension systems are somewhat hydraulic, we can not call the ahc a hydraulic suspension system.
What do we call it then? I don't know - Maybe a hybrid air suspension system? Or just AHC - TEMS.

It’s a hydraulic suspension system in this truck that has dampening of the fluid aided by bladders in the globes. The springs are for the small bump low load compliance and rebound. It has a hydraulic pump pumping hydraulic fluid.

An airmatic system in Mercedes is air in bladders and lines dampened by shocks and aided by springs. It has an air pump and air tank.

An abc system in Mercedes is hydraulic with globes, assisted by springs.

I have all three in my driveway.

Basically, the difference between air and hydraulic is that one uses an air pump and the other uses a hydraulic pump. Lexus is hydraulic, and not hybrid, by any sense of the definition.

Lexus also has cars with air bladders and springs….