Rear Airsprings (replace coils with full airbags)

[Jetboy]

Has anyone done a conversion to gx460 rear air springs? I've been trying to work toward a perfect all around vehicle for me. And part of that goal would be adjustable suspension so I can drop it low for daily driving/road trips, and swap in big tires for the trails with adjustable height.

Air springs are probably going to be part of the program. I wasn't thrilled with the ride quality of my 3rd gen with firestone airbags inside the coils. I loved the height adjustments, but didn't love the firmness at normal ride height. So... I'm thinking GX460 rear air springs could be a perfect fit and would give me both good flex and ride height adjustment of 3-4".

Has anyone done this? The only similar swap I've seen is this guy: Airsprung CNG äFJii - Toyota FJ Cruiser Forum

Also - if you're interested I love what he did with his drop bracket 3" lift. That's what a 3" lift should be IMO. I'm actually thinking of doing something similar but maybe only a 1.5" modified drop bracket with a 1" forward relocation. But that's not going to happen for a few months at least. I might toss the airbags in asap to go test them in Moab at Cruise Moab. The front is going to require getting rid of the fox 2.5s and moving down to a 2" body to fit an air bag. That's for a future day.

 

[Zeder]

Holy modifications Batman! The airbag system is a very cool mod.
Z

 

[The Waco Kid]

Wow... Consider me subscribed if you do this. That guy's build is awesome.

:snacker::snacker::snacker::snacker::snacker:

 

[Swarty]

Sweet!

Has anyone done a conversion to gx460 rear air springs? I've been trying to work toward a perfect all around vehicle for me. And part of that goal would be adjustable suspension so I can drop it low for daily driving/road trips, and swap in big tires for the trails with adjustable height.

Air springs are probably going to be part of the program. I wasn't thrilled with the ride quality of my 3rd gen with firestone airbags inside the coils. I loved the height adjustments, but didn't love the firmness at normal ride height. So... I'm thinking GX460 rear air springs could be a perfect fit and would give me both good flex and ride height adjustment of 3-4".

Has anyone done this? The only similar swap I've seen is this guy: Airsprung CNG äFJii - Toyota FJ Cruiser Forum

Also - if you're interested I love what he did with his drop bracket 3" lift. That's what a 3" lift should be IMO. I'm actually thinking of doing something similar but maybe only a 1.5" modified drop bracket with a 1" forward relocation. But that's not going to happen for a few months at least. I might toss the airbags in asap to go test them in Moab at Cruise Moab. The front is going to require getting rid of the fox 2.5s and moving down to a 2" body to fit an air bag. That's for a future day.

What's the travel on those airsprings?

 

[Jetboy]

What's the travel on those airsprings?

I'm not sure. I think it's the same as the coils - limited by the shocks and bump stops.

 

[Jeremy556]

Although the mfg says to keep the airbags at 5psi when not in use, I keep the valve core removed until the rare occasion that I am towing, when I install the core and inflate. At atmospheric pressure they don't make any difference in the spring rate during normal use, and can still hold 30psi to restore normal ride height when towing with 500+lb tongue weight. Have had no problems keeping them uninflated, they just kind of float around inside the coils, suspended by the airline.

 

[Swarty]

Right...

I'm not sure. I think it's the same as the coils - limited by the shocks and bump stops.

But the shock and bump stop travel is very likely not the same between these two vehicles... Be nice to find a Toyota spec on these.

 

[mikey's2010SR5]

But the shock and bump stop travel is very likely not the same between these two vehicles... Be nice to find a Toyota spec on these.

You would be surprised. They are the same platform.

 

[Swarty]

Not a risk I would take..

You would be surprised. They are the same platform.

Don't get me wrong I like the idea behind this but you have to get suspension right. The GX has adjustable dampening shocks a luxury ride, weighs 700 lbs more and can tow 2000 lbs more so they are at least a little different. Does Toyota expect people to flex the GX? Did they design the suspension for only minor flex? Do the seals fail if consistently taken past a certain limit in compression or extension? Do they have extension that matches my shocks so they don't fall out? What if I use extended travel shocks? Do they still work? Maybe these are awesome and extend well past stock and I can use these with the Metal tech extended travel shocks. Unlikely but a man can dream!

But considering what happens if I get this wrong I'd want to know the specs.

 

[CruzadoBlanco]

Don't get me wrong I like the idea behind this but you have to get suspension right. The GX has adjustable dampening shocks a luxury ride, weighs 700 lbs more and can tow 2000 lbs more so they are at least a little different. Does Toyota expect people to flex the GX? Did they design the suspension for only minor flex? Do the seals fail if consistently taken past a certain limit in compression or extension? Do they have extension that matches my shocks so they don't fall out? What if I use extended travel shocks? Do they still work? Maybe these are awesome and extend well past stock and I can use these with the Metal tech extended travel shocks. Unlikely but a man can dream!

But considering what happens if I get this wrong I'd want to know the specs.

im pretty sure they use the Xreas shock system along with kdss. the Xreas is pretty easy to remove and get rid of. plus metaltech sells a spring perch kit to convert to coils in the rear, so i dont see it being an issue. one thing im not sure about is if the air springs are fixed at top and bottom or not.

 

[Jetboy]

All fair questions. I'm ordering the air bags today. I'll update this when I get them installed. FWIW - I checked yesterday and the spring brackets on the top end are the same - ie they are already cut out in the proper spots for the air springs to mount and pass through for the air fittings. The air hose mounting locations are there too.

As of now I'm intending to go with OEM air springs because it's very easy, but I'll probably make a final decision later today before I order. I may go with generic air springs and make my own bolt on end caps to fit in the OEM location for longer travel. Not sure on that yet. I happen to be fortunate enough to have a CNC router in my garage so I can make plastic bolt on ends for generic airbags to seat in the OEM location without any permanent mods to the 4runner. The big advantages with this route is more travel and larger diameter bags for softer ride. The bags are cheaper as well and use 1/4npt fittings rather than Toyota specific fittings. There are a lot of Goodyear and Firestone bag options. With the OEM style, there is Toyota ($650 each) or aftermarket no-name for $100 each, but probably low quality. The downside is that it will take a few more hours to draw and cut the end caps. Interfacing with a compressor system is likely the same either way.

 

[Swarty]

Not sure what you are trying to say...

im pretty sure they use the Xreas shock system along with kdss. the Xreas is pretty easy to remove and get rid of. plus metaltech sells a spring perch kit to convert to coils in the rear, so i dont see it being an issue. one thing im not sure about is if the air springs are fixed at top and bottom or not.

I'm not sure of the logic there :shrug:, Metal tech thinks they need to be removed for a lift so they make a kit. Wouldn't that suggest that they are travel limited? Metal Tech's comments for that kit suggest they think the airbags are crap. The fact that metal tech is removing them for coils in the first place is not a good sign.

GX460 has a knob that adjusts damping on the shocks so it's not xreas. A similar system was an option on the 4th gen limited 4runners and those may have used xreas but I'm not sure. Xreas or KDSS would make sense since airbags offer less stability than springs(non-linear change in spring rate) and usually require more aggressive sway control on road.

 

[Jetboy]

People go both ways. Metaltech makes money by selling springs... Some remove airbags for coils. In Australia it's common to swap coils out and replace with airbags. I think it's a matter of what you want and whether you're willing to replace the airbags every 5years or so. Tossing a spare spring in the back for long off road trips is pretty easy backup. Who knows. May be a really bad idea. I'll find out. It's a cheap experiment. If it sucks it's easy to go back.

 

[nevada]

I haven't check the link in the op, so perhaps its already been addressed.


but, what do you plan to do about camber/toe changes when the ride height changes?

you mentioned lower for in town use, then higher for off road/large tires.

would you get it realigned each time? seems like a huge PITA.

 

[Swarty]

Not on a solid axle.

I haven't check the link in the op, so perhaps its already been addressed.


but, what do you plan to do about camber/toe changes when the ride height changes?

you mentioned lower for in town use, then higher for off road/large tires.

would you get it realigned each time? seems like a huge PITA.

He's not changing the front just the rears. the rear has no camber or toe since it's a solid axle. The change in angle won't be enough to drastically affect front alignment.

 

[Jetboy]

I haven't check the link in the op, so perhaps its already been addressed.


but, what do you plan to do about camber/toe changes when the ride height changes?

you mentioned lower for in town use, then higher for off road/large tires.

would you get it realigned each time? seems like a huge PITA.

For now I'm just doing the rear. I have Fox coilovers in the front that I'll manually adjust.

The alignment shouldn't move much through the range with the geometry of the current IFS system. However the idea would be that 90% of the miles are done near stock height, so you'd set the alignment for stock height. Even the highway to the trails would be at the lower height. Possibly you'd only raise it for trail obstacles when necessary. In a perfect world I'd have a 2" drop bracket style lift and set it as low as practical. Then at 3" lift I'd still have almost a full OEM range of travel. For the other miles you'd just accept a slight out of camber condition. I actually don't know which way it goes in this case. But that's an issue for another day.

I did order a set of GX460 air springs. Should be here next week. For now I'm just going to stub out some schraeder valve fill hoses to see if I like it. If I do I'll put a full controller unit in. Total cost will be $200 for the air springs, $40 for a Firestone air hose kit. And $35 for the Toyota OEM height control tube to cut both ends off for an OEM fitting at each airbag and then adapt them to the firestone air hose lines. With a few odds and ends I'll probably be about $300 into this experiment. The wireless control set will be another ~ $300, so I'll then be into it more like $600. But I'm not going to do the second step before I get a chance to try it out.

It very well could be total crap an I'll rip them out. I have no idea. I'll find out soon.

 

[Jetboy]

It's happening today if I can find an OEM toyota air hose for the end fittings to interface with the bags. If not - I'll probably just cut the fitting off and drill/tap them out to 1/4 NPT.

Also FWIW - the GX460 airbags are NOT the same as GX470 and 4runner. They have an extra plate welded to the bottom for a flat mount and a threaded stud on the bottom to provide more than just a friction retention. Apparently on a lifted long travel GX470 you can flex enough to pop the bag out of place. (TrailLex did it once). So I'm probably okay with it - but I'll need to cut some adapter plates and weld up a small spacer/adapter on the lower end. Not a big deal.

 

[Zeder]

Good Luck! I am very interested to see how this turns out. Please keep us posted on your progress.

Cheers,
Z

 

[Jetboy]

Well, turns out air lines are unobtanium. Neither lexus dealer stocks any of the air hoses for any model. So... if the local hose supply house can't make one I'll drill it out and tap for an npt size.

Also - don't buy air suspension from Lexus/Toyota because any problem is unfixable unless you are going to stock your own parts or make them yourself. At least in this case I'll carry spare coil spring and if I like air - I'll put a spare air spring in my trail bag with a spare hose assembly.

 

[Ron4RNevada]

Hmmm - Funny how things change over time:

When Land Rover started putting air suspension in their trucks all of the off-roaders started modifying them back to springs - - -