Replacing the rear air suspension with coils and keeping auto leveling?

[Merle]

My 4Runner like quite a few others came with X-REAS and the auto leveling rear air suspension.

Replacing the X-REAS is straight forward, four new shocks (OME), as is changing the front springs to support a Shrockworks bumper, winch, Budbuilt Skud plate - more OME.

There are threads for changing out the RAS with coils, but is it possible to continue to use the compressor and auto-leveling feature bits?

I am looking at the Airlift 1000 or Firestone Ride Rites, both about $90 from Summit Racing (leaning towards the Firestone one because of the quality of the connector.

So... Anyone do this, or try? Would the existing air hoses hook up and the compressor cut when the load is considered "level"?

Thanks for any insight or opinions!

 

[ARK_SWAMP_RIDER]

After the swap, my compressor still works. It would be a matter of hooking the hoses up and dialing in the height, but I'm nearly positive it can be done. My only concern is going too high or low with the pressure and damaging the bags.

 

[ebg18t]

My only concern is going too high or low with the pressure and damaging the bags.

Exactly. Unless you can find a way to add an outside controller I think you are going to ruin an airbag. I don't believe the operating range of the OEM system is the same as the Firestone add ons. But as I mentioned if you could plumb in a controller and seperate gauge, the compressor will be able to handle it.

 

[ARK_SWAMP_RIDER]

Exactly. Unless you can find a way to add an outside controller I think you are going to ruin an airbag. I don't believe the operating range of the OEM system is the same as the Firestone add ons. But as I mentioned if you could plumb in a controller and seperate gauge, the compressor will be able to handle it.

I know of another member who had the dealer do something that allowed manual control of the air bags using the OEM switch. Unfortunately they don't know what exactly was done. This would help, but you still have the issue of the not knowing where the pressure is.

I was going to try this, but I've towed several times since my swap to the Overland Warehouse kit and I don't feel they're needed for my uses. Still have it in mind, but I've got quite a few other mods that will take priority.

 

[Merle]

I may be off base, but unless the compressor is blowing in a massive amount of CFM, shouldn't things be fine?

I was able to find some of the specs on the Firestone compressor:

Firestone "Standard Duty" Air Compressor (Up to 1 gallon tank) - 9284 | $85.00

And wouldn't think these are too far off from what the stock Toyota compressor would be (or what I use to air up my tires).

Max Air Pressure: 130 PSI (9.0 BAR)
Duty Cycle: 15%
Amperage Draw: 18 AMPS
CFM @ 60 PSI: 0.64
CFM @ 100 PSI: 0.57

In addition, wouldn't the circuit be open (compressor cut) when the height sensor meets the "level" condition (or the +/- depending on how ours are set) instead of going off of the PSI of the air bags?

Ideally, I'd like to get a 30 PSI inline breaker / safety (either to physically cut the power to the compressor or the blow off excess pressure) to keep the compressor from over working itself.

So...

1. Worst case - I blow one of a pair of $86 air bags. Followed by the stock compressor because of exceeding it's duty cycle
2. If I went coils - what do I have to pull to tell the system "Stop" with the stock compressor?

Again, thanks!

 

[ebg18t]

Merle - like indicated it is all about controlling the OEM compressor. I went thru the repair manual and I cannot find the exact operating perimeters. A compressor is a compressor; the controller is the key. If you can find a way to have an inline controller you will have a great setup.

 

[Merle]

Well, I'm game. Let me see what I can do then

1. What shock should I go with for the rears? Fronts I have OME 886's and don't have any load (no aftermarket bumper) on the rear.

EDIT: Pulled the trigger on a pair of 895's from Wheelers.

2. What does it take to remove the rear air shocks? Jack up the car, and then...?

EDIT: Found this thread again! http://www.toyota-4runner.org/4th-gen-t4rs/120196-how-convert-ras-coils.html#post1123899

3. Anyone that has removed the rear air (Ark?) and can describe the connector, closer? The Firestone airbag connector looks like a screw on, while the Airlift looks like it's held on by cable ties

 

[ARK_SWAMP_RIDER]

Here's a pic of the air line and the connector. Sorry I couldn't get a better pic, but I think this will help. The air line is very small in diameter and you can see the white connector that holds it on (it's slid down the line, normally it's at the very tip). For lack of a better description, it's H shaped so push one the rear and it widens the front and it'll pull off. You probably won't use this once you swap.

If you have any questions on the swap, let me know. It's pretty easy overall.

A couple things to mention on the aftermarket air bags. I *believe* the airlift's have you route the air line at the bottom (through the hole that I used to mount the brackets to hold the coils in place) while the Firestone's route through the top (going through the upper isolator). The Firestone design would work better if you're planning to use brackets similar to mine. Also, since you have bigger than stock coils, you may need bigger air bags than those listed for the 4runner. A little more info: Airlift 1000 installed - Toyota 120 Platforms Forum.

Another note, those OME 895's are very stiff, I think approx 45% stiffer than stock. Unless you tow heavy loads frequently or have added weight, I think they're going to be too stiff. I'm running OW coils (approx 20% stiffer than stock) and wouldn't want to go any stiffer at stock weight (I carry ~75 pounds of gear in the rear at all times). Here's an example: http://www.toyota120.com/forum/showthread.php?t=22750

 

[08T4R]

I don't have ras, nor have I ever seen it on a 4r, but I'm curious how it limits the travel? Obviously I've seen air suspensions on trucks before and they use a limit switch. For a visual its kind of similar to the shut off valve in a toilet. What is under the 4r to control the height, or tell the computer what height its at? Obviously you've been under yours to take pics of the line. Have you noticed anything under there that would relay this to the compressor? I mean I guess I could find a FSM and look, just figured you might have seen something under there..

Here's a pic of the air line and the connector. Sorry I couldn't get a better pic, but I think this will help. The air line is very small in diameter and you can see the white connector that holds it on (it's slid down the line, normally it's at the very tip). For lack of a better description, it's H shaped so push one the rear and it widens the front and it'll pull off. You probably won't use this once you swap.

If you have any questions on the swap, let me know. It's pretty easy overall.

A couple things to mention on the aftermarket air bags. I *believe* the airlift's have you route the air line at the bottom (through the hole that I used to mount the brackets to hold the coils in place) while the Firestone's route through the top (going through the upper isolator). The Firestone design would work better if you're planning to use brackets similar to mine. Also, since you have bigger than stock coils, you may need bigger air bags than those listed for the 4runner. A little more info: Airlift 1000 installed - Toyota 120 Platforms Forum.

Another note, those OME 895's are very stiff, I think approx 45% stiffer than stock. Unless you tow heavy loads frequently or have added weight, I think they're going to be too stiff. I'm running OW coils (approx 20% stiffer than stock) and wouldn't want to go any stiffer at stock weight (I carry ~75 pounds of gear in the rear at all times). Here's an example: Cant live with OME suspension anymore - Toyota 120 Platforms Forum

 

[ARK_SWAMP_RIDER]

I don't have ras, nor have I ever seen it on a 4r, but I'm curious how it limits the travel? Obviously I've seen air suspensions on trucks before and they use a limit switch. For a visual its kind of similar to the shut off valve in a toilet. What is under the 4r to control the height, or tell the computer what height its at? Obviously you've been under yours to take pics of the line. Have you noticed anything under there that would relay this to the compressor? I mean I guess I could find a FSM and look, just figured you might have seen something under there..

I think the FSM explains it better than I can. I've attached this section, look it over and it should give you an idea.

 

[08T4R]

I think the FSM explains it better than I can. I've attached this section, look it over and it should give you an idea.

Awesome. Page 25-6, that diagram on the lower left is an adjustable limit switch. It should look similar to a sway bar end link when you're under there. After you install the coils and new helper bags, you should be able to adjust this to set the different heights you want... at least that's the way the FSM says it.

I would think it would be a fairly simple process, just a little trial and error to get the heights right.

 

[ARK_SWAMP_RIDER]

Awesome. Page 25-6, that diagram on the lower left is an adjustable limit switch. It should look similar to a sway bar end link when you're under there. After you install the coils and new helper bags, you should be able to adjust this to set the different heights you want... at least that's the way the FSM says it.

I would think it would be a fairly simple process, just a little trial and error to get the heights right.

Yes, not hard at all. I originally adjusted these to lift the rear 2" prior to swapping to coils.

 

[Merle]

Here's a pic of the air line and the connector. Sorry I couldn't get a better pic, but I think this will help. The air line is very small in diameter and you can see the white connector that holds it on (it's slid down the line, normally it's at the very tip). For lack of a better description, it's H shaped so push one the rear and it widens the front and it'll pull off. You probably won't use this once you swap.

If you have any questions on the swap, let me know. It's pretty easy overall.

A couple things to mention on the aftermarket air bags. I *believe* the airlift's have you route the air line at the bottom (through the hole that I used to mount the brackets to hold the coils in place) while the Firestone's route through the top (going through the upper isolator). The Firestone design would work better if you're planning to use brackets similar to mine. Also, since you have bigger than stock coils, you may need bigger air bags than those listed for the 4runner. A little more info: Airlift 1000 installed - Toyota 120 Platforms Forum.

Another note, those OME 895's are very stiff, I think approx 45% stiffer than stock. Unless you tow heavy loads frequently or have added weight, I think they're going to be too stiff. I'm running OW coils (approx 20% stiffer than stock) and wouldn't want to go any stiffer at stock weight (I carry ~75 pounds of gear in the rear at all times). Here's an example: Cant live with OME suspension anymore - Toyota 120 Platforms Forum

Thanks, very helpful!

The Firestones are what I was leaning towards so with your additional information, I'm thinking that cements it. We have a Summit Racing in Reno NV which has both (generally everything in stock there) so I should be able to bring in the rear springs and see if I can get a good fit. Just concerned about mating the connectors to the stock compressor hosing. Will also have to nail down that coil isolator too (drill through the middle after chopping half of it off?)

As to the 895's, it looks like the FJ Cruiser guys have done some research and they're coming in about 37% stiffer.

Rear Spring Comparison - Toyota FJ Cruiser Forum

So... 37%... You're saying I /need/ more weight back there eh?

Fine, I hear ya,I need something like this Toyota 4Runner Rear Bumper: 4th Gen 4Runner, Cbioffroadfab as that'll add 200# give or take, and make use of the spring rate!

Today, new GYSA's ($68 installed). Thursday, new springs (front only!) and shocks (4!) going in. Should see an increase in the front (stock Shrockworks comes in R/L at 34.5" and 35" today) height. Saturday new winch, and hopefully Budbuilt will come through next week or so. Wheelers usually delivers in <10 days, so in two weeks I should have the air bag thing squared away in 2-3 weeks.

Anyone have ideas as to which model of the Firestone would be the best fit for OME 895's? Quick link to some imagery. Firestone Coil-Rite Air Helper Spring Kits - SummitRacing.com with the 4135 seemingly the one for "stock" situations, measuring 4.75" x 7.50" Ride-Rite Installation Instructions

 

[Merle]

Well, reached out to Wheelers and got some wisdom:

1. The isolators they have listed under OME are only for the front. They're going to be looking for some option for the rear.
2. The rear shock actually limits travel, so a bottom mount isn't generally necessary.

The isolators you listed are for
the front suspension and would not work the same. I will have to check
around and see if I can get the rear as well.

Generally, your shock is supposed to stop the travel before you spring can
pop off the lower mount. Making the bracket unnecessary. Typically,
using the OME spring, in conjunction with the OME shocks, you should not
have any issues with the springs popping out of place.

Going to get in there and measure the current height to see if the firestones with their 7.5" height will fit (hopefully not too short)

Anyone who has done this, can you see what the current distance is at rest or even at full extension?

 

[gtrikk]

I know it's been years since this thread but was wondering if anybody had any luck swapping the stock airbags with the Firestone or any aftermarket airbags when lifting the rear with aftermarket coils?

 

[jminz]

I know it's been years since this thread but was wondering if anybody had any luck swapping the stock airbags with the Firestone or any aftermarket airbags when lifting the rear with aftermarket coils?

I never had stock airbags, but did install Firestone bags when I installed my toytec superflex coils. They are too cheap and easy to install to not go ahead and buy them and put them in while you have everything apart.

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