Getting Started and Need Suspension Advice (2006 w/AHC)

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Joined
May 6, 2021
Threads
1
Messages
9
Location
'Murica
I love my Toyotas and picked my first Cruiser a couple of years ago before prices went bonkers. I've been searching and scrolling the forums and feel like I've learned a ton, but with more knowledge comes more questions. Thank you to all who have posted such in depth, useful and helpful info. I've already replaced all speakers, isolated various little issues and avoided serious headaches because of the generous sharing of experience and knowledge here, and I will offer my experience here as I build out my rig.

She is 2006 Cruiser with AHC and straight stock 100% dealer serviced. When I made the purchase there were 97k miles on the clock, now sitting at 158k, major items so far have been timing belt, CV axles, brakes and new headlight fixtures.

On order I have front (with winch) and rear bumper kits (with dual swing outs) from 4x4 Labs, I just received the 24 gal rear aux tank from Exit Off-Road and I'm just about settled on the the roof rack from Bowfin.

My question is what to do about my suspension. I'm a 90% highway driver, I do drive in the mountains of the northest during ski season, fire break roads, class 6 roads (aka not maintained or dirt), on beach driving in the summer and high speed washboards (that's what every highway in Maine or New Hampshire is to me anyway) is the extent of our adventures so far. I sometimes have to drive to work in the kind of weather that even snow plow trucks avoid so my desired build is to support the additional weight while keeping my AHC. The AHC is functioning as advertised but I suspect the globes are getting tired (9 ticks counted on the low to high test).

My current plan is as follows:
1) Replace the globes with OEM from Impex and flush system in the process
2) Crank and/or re-index torsion bars as required
3) Replace rear springs with ones better suited for the additional weight
4) Lift is not necessarily desired, but if this setup is workable I may employ a mild sensor lift

What I hope to accomplish:
Both of my stock bumpers have been smashed by knuckleheads in parking lots giving me the green light to upgrade to steel bumpers. I like welding projects and Luke's kit looks incredible. I give zero F's about MPG, but would like to venture further out than 20 gal of fuel will allow and I've always hated hauling gas cans so the aux tank filled that desire. Hardcore wheeling is not for me, I want my kids and wife to have fun, not s*** their pants. So basically a solid daily driver that can overland a couple times a year, go camping on the beach on the weekend and look good doing it.

All critiques and suggestions are welcome, while I generally know cars pretty well, this AHC is totally new to me. I really like driving it, but I'm clueless as to the pitfalls once I start outfitting my rig with all this extra weight.

Things I really need help with: before I talk to vendors who and what should I look at for rear springs and where can I source Tech Stream that runs on Mac?

Thanks in advance
 
First off, welcome to ih8mud! Tons and tons of information here from mods to basic maintenance of your cruiser. I have an 06 too, still on AHC and will keep it for as long as I possibly can. Your suspension plans sounds solid (re-index, upgrade to heavier capacity coil springs and torsion bars, etc,) the hydraulic (AHC) system basically carries out 50% of the body’s weight. The more your cruiser carries, the more stress the AHC system tries to manage, the higher pressure it tries to mitigate.

“Constant” High AHC globe pressures may affect/shorten the system’s lifespan. AHC is robust, but like any other system, it has it’s own limits. I guess the key factors in maintaining a healthy AHC system is about being aware of two things: 1.) pressure on the globes, and 2.) how much weight are we carrying. -this is all assuming the AHC fluid is fresh and new and there is no leak anywhere. AHC fluid is the life and blood of the system.
 
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First off, welcome to ih8mud! Tons and tons of information here from mods to basic maintenance of your cruiser. I have an 06 too, still on AHC and will keep it for as long as I possibly can. Your suspension plans sounds solid (re-index, upgrade to heavier capacity coil springs and torsion bars, etc,) the hydraulic (AHC) system basically carries out 50% of the body’s weight. The more your cruiser carries, the more stress the AHC system tries to manage, the higher pressure it tries to mitigate.

“Constant” High AHC globe pressures may affect/shorten the system’s lifespan. AHC is robust, but like any other system, it has it’s own limits. I guess the key factors in maintaining a healthy AHC system is about being aware of two things: 1.) pressure on the globes, and 2.) how much weight are we carrying. -this is all assuming the AHC fluid is fresh and new and there is no leak anywhere. AHC fluid is the life and blood of the system.
Thank you. That confirms my understanding of the theory of AHC operation.

Any suggestions on rear springs or where to source Tech Stream for MAC so I can dial in my pressures?
 
I use techstream on my old laptop, software is free to download and the dongle is inexpensive.
 
You may want to check out this thread before you get into that aux tank install.

As far as AHC goes, you're on the right track. The hydraulics can only support so much, additional weight will have to be taken up by upgrading the springs. I found all the info to run Techstream on my Mac here.
 
I was in a similar situation a few years ago with mine - also an '06 with AHC, bought with around the same mileage and so on.

When I got it my initial plan was to just rip out the AHC off the bat and install a new suspension because of all the "what ifs" - age, dependability, wheelability, etc.

After a few months though with mostly commuting and a couple of forays on dirt roads I learned I really liked the AHC. Read threads from @LandCruiserPhil and the like. They convinced me to hold onto mine for about a year and a half. It's a fantastic system in the right circumstances.

Once I started adding weight it became the enemy I think of the AHC, which I think most will agree it can handle but is not necessarily designed to, and the ride began to suffer a little. It went from cush to bouncy and after adding AHC lift, spacers in the rear it just started to require more fiddling than I cared for.

At the point I decided to change it out I had only added sliders and a rear tire carrier. Having said that I cart around mountain bikes a lot and the ride just didn't do it for me anymore. Towing a light trailer exaggerated this.

I may have gone a little nuts but I went with the Just Differentials lift with Icon Bypass shocks and I can tell you - IT RIDES AS WELL AS THE AHC BEFORE ADDING THE WEIGHT. Having said that I can put as much weight on it now as I want and the suspension doesn't flinch.

Sorry so long, but AHC is a great system. It does have its limits though.
 
You may want to check out this thread before you get into that aux tank install.

As far as AHC goes, you're on the right track. The hydraulics can only support so much, additional weight will have to be taken up by upgrading the springs. I found all the info to run Techstream on my Mac here.
That's very helpful thank you
 
I was in a similar situation a few years ago with mine - also an '06 with AHC, bought with around the same mileage and so on.

When I got it my initial plan was to just rip out the AHC off the bat and install a new suspension because of all the "what ifs" - age, dependability, wheelability, etc.

After a few months though with mostly commuting and a couple of forays on dirt roads I learned I really liked the AHC. Read threads from @LandCruiserPhil and the like. They convinced me to hold onto mine for about a year and a half. It's a fantastic system in the right circumstances.

Once I started adding weight it became the enemy I think of the AHC, which I think most will agree it can handle but is not necessarily designed to, and the ride began to suffer a little. It went from cush to bouncy and after adding AHC lift, spacers in the rear it just started to require more fiddling than I cared for.

At the point I decided to change it out I had only added sliders and a rear tire carrier. Having said that I cart around mountain bikes a lot and the ride just didn't do it for me anymore. Towing a light trailer exaggerated this.

I may have gone a little nuts but I went with the Just Differentials lift with Icon Bypass shocks and I can tell you - IT RIDES AS WELL AS THE AHC BEFORE ADDING THE WEIGHT. Having said that I can put as much weight on it now as I want and the suspension doesn't flinch.

Sorry so long, but AHC is a great system. It does have its limits though.
These are my concerns as well and thanks for sharing what system you ended up with
 
Just Differentials lift with Icon Bypass shocks

Is Icon now making “bypass” shocks for the 100 series, or are you talking about the monotube stage 1 (IFP), 2 (remote reservoir), 3 (remote reservoir with compression adjuster), that’s been around for a while?
 
Yeah sorry got a little ahead of myself... remote reservoir.
 

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