Air bag suspension

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Again!

And before the Search Police get out their ticketbooks, yes, I did a search and read everything I found!

:)

So here's what I want to do.

I'd like to keep the OME springs and shocks in place, and leave them as my normal suspension system.

I'd like to add 4 airbags to add lift to the vehicle to clear obstacles on the trail. This would be their only use. They wouldn't interfere with the suspension otherwise. They could be inflated (individually) as necessary to clear obstacles, then deflated immediately after and return to the normal coil spring suspension system.

Is this possible? Or would the coil springs need to be replaced by air springs to accomplish this?

Has anyone seen this idea incorporated into any kind of offroad truck? I saw pictures of an 80 with airbags, but they had replaced the coil springs.
 
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A bunch of yess .. maybe the odd no .. :flipoff2:


Search again, I think I started a thread similar to this, and guys gave me a few leads on good air bag manufacturers.


:cheers:



TY
 

e9999

Gotta get outta here...
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the usual airbags people talk about here, the ones that fit in the coils are not raising the rig IIRC, they just "stiffen" the coils. Different idea I think.

There are air "springs" used on pickups etc, but that would probably take some fabbing to install...

not that I know anything about any of this... :D
 
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FirstToy said:
search button newbie! hehe, just kidding Dana :D

dealmaker found this link- it's Jeep only but maybe it will lead you to more things
http://www.offroadonly.com/products/suspension/airock/index.shtml


Yeah, I saw that one, but it replaces the coil springs.

I'd really like to avoid that if at all possible, because I really don't want to have to rely on air springs to support the vehicle all the time. The coils are low tech, they don't leak, they work fantastic for 99% of the trail, etc. etc.

I only want the airbags to clear obstacles, that's the only time they'd be called upon to do anything. The rest of the time, they'd just sit there doing nothing.

At least, that's what I envision.

Am I dreaming?

:grinpimp: :grinpimp:

Maybe I do need to replace the coils wth air springs, then (theoretically) you could adjust height from 2" to 6" lift from the cab! I do like that idea. Of course the ride would change substantially, but if 99% of the trail is done at 2" lift (comfortably), then you pump up to 6" for that big rock, it's going to be a lot stiffer ride with more air in the bag. But after you clear the rock, let out the air.

This is what I want to do, PREFERABLY with out losing the existing coils.

I probably need to visit a shop in east L.A. that does the "bouncing trucks" and see what they say about my idea.

:)
 
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Doesn't Peter Straub up in Canada have air bags on his huge lifted FJ60? he'd be one to contact; check the 60/62 boards.

I know from Land Rover friends that airbags can fail at the most inopportune times--LR owners swap them out for regular coil springs. This includes the new versions that lift the Disco and/or LR3 higher or lower, as you are planning for. FWIW. Your system can't be any worse than what the Brits designed!:eek:

Dave
 
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Alan Podvin has done the spring replacement. I have not seen it nor do I know which manufacturer he went with but maybe others will chime in. Firestone seems to make a pretty good "airspring". If you are going to go that route I would go all the way. They seem to work great for semi's.
 

Brentbba

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Airlift airbags that fit inside the coils will not provide additional lift. Ok - I see the truck raise maybe 1/2 inch (never measured) when I air them up before I tow. Don't think these type airbags would provide you with what you are after.
 
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I have a set of airbags inside my rear STOCK coils. When they are inflated they will push the rear end up 4 inches, but they leak. I don't know if it is too much pressure (I doubt it, only 30 to 40 psi). I think one of the air hoses to fill them is cracked. They are tied together, so if they did not leak they would help with articulation on the rear.

I will be pulling them out this spring when I put on OME suspension. I would give them to you if you pay shipping. PM me.

I have contacted www.offroadonly.com , their airbags are rated for 2200lbs each and could be adapted to a fj80, but $$$. There is also a vendor in Oz that makes a front and rear kit designed for the 80 series, www.airbagman.com.au
 

Brentbba

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Jule said:
I have a set of airbags inside my rear STOCK coils. When they are inflated they will push the rear end up 4 inches, but they leak. I don't know if it is too much pressure (I doubt it, only 30 to 40 psi). I think one of the air hoses to fill them is cracked. They are tied together, so if they did not leak they would help with articulation on the rear.

I will be pulling them out this spring when I put on OME suspension. I would give them to you if you pay shipping. PM me.

I have contacted www.offroadonly.com , their airbags are rated for 2200lbs each and could be adapted to a fj80, but $$$. There is also a vendor in Oz that makes a front and rear kit designed for the 80 series, www.airbagman.com.au

4 inches of lift on a stock height coil - I call bulls***. I've got stock height OME rear coils and there's not a snowballs chance in hell when fully inflated that the truck lifts 4 inches. RTFM while you are at it - max psi on Airlift airbags is 30psi, 25psi on some of their documentation. Yes - they do leak some, that's why doing the RTFM will tell you that they say to check the pressure WEEKLY. 4 inches my ass!
 
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I've looked into this a bit myself. Here's the deal - you can't run airbags on top of springs without the bags contributing to the suspension normally. This is because there is a minimum amount of air you need in them.

You could run air bags instead of the coils. This would give you the adjustability. The down side is, the more air pressure, the more lift, the greater the spring rate. So yes, you could set up the bags to run at stock height or 4" over stock, or what ever height you deside based on the attachment cup length. And if you want to raise it to get over an obstical you can. The only possible problem, and maybe the times you want the extra height this won't matter, is you no longer have as good of articulation. Think of it this way, at normal height, you're running say 30psi, which is 300lbs/in spring rate on the bags you pick. Then you pump it up to 60psi, to raise it a couple inches, and now the spring rate is 450lbs/in. It's higher but stiffer. Unfortunately what most would really like is the exact opposite, stiffer at low height for good road manners, and soft at off-road, obstical clearance height, to get more articulation.

If you really want to run on springs, and then want to be able to raise it, and not change the spring rate - use hydrolics. Which is most likely what Dusty was seeing hopping in Cali as bags haven't been able to inflate and deflate fast enough to hope till resently. Pick-up an issue or two of Lowrider (I'm going to catch crap for saying that) - you'll find out a bunch about air bags, hydrolics, and air cylinders. Now, what you want to do is you're not going to replace the springs with hydrolic cylinders and use and accumulator for cushion, like some low riders do. Those are the ones you see bouncing down the street cause there isn't much suspension movement independent of flipp'n the switches. What you want to do, is hook up a hydrolic cylinder (or you could use an air cylinder) to the top spring perch. And what you're basically going to have to figure out how to do is make the spring perch go up and down. I've seen some like this for dancing contests, with hydrolic over springs. You're going to want to use it a bit differently, as you'll want full length springs.

If I was doing a hydrolic over spring set-up, I'd rig up a bell crank so I could lay the cylinders (air or hydrolic) horizontally along the frame - keep them from sticking out the hood. Then I'd mount both the shocks and the springs to the other arm of the bell crank. That way, when you raise the suspension, you're not over extending the shocks. Though some super long travel shocks would work too. I'd put a bump stop (solid most likely) at the ride height I wanted to keep the bell crank from spining, and make it so the load isn't on the hydrolic cylinder at that level. That way any compression in the hydrolic system isn't going to influence your spring rate at that height. The bell crank, if the arms are the right length and pivoted right, will also point the springs more perpendicular to the axle. Remember, and the front arms go down, the axle rotates counter-clock-wise from the driver side, and moves toward the back of the vehicle. The other advantage to using what is basically an adjustable spring mount, with a solid stop, is if anything in the system fails, it's simply ridding on the stops, and performing like a normal vehicle.

It would work really cool as you could run as low as you wanted on the street or as high as you wanted (within your design parameters) off road, and the spring rate would be the same. The question is - is it worth the time and money to put a system like this on your truck? You could do straight air bags for under 2 grand if you already have the rest of the lift parts if you're setting "normal" to X over stock. The mounting cups would be pretty easy to fab, the rest of the system, the controllers, compressors, valves, are all readily available. Fabbing up a hydrolic over spring system, that would be a challenge.
 
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Brentbba said:
4 inches of lift on a stock height coil - I call bulls***. I've got stock height OME rear coils and there's not a snowballs chance in hell when fully inflated that the truck lifts 4 inches. RTFM while you are at it - max psi on Airlift airbags is 30psi, 25psi on some of their documentation. Yes - they do leak some, that's why doing the RTFM will tell you that they say to check the pressure WEEKLY. 4 inches my ass!

See Pics Below: 14 7/8" @ 0 psi, 18 5/8" @ 40 psi, 19 1/4" @ 45 psi

I have FACTORY OEM coils, not OME (Old Man Emu) coils. I believe the stock height OME springs are stiffer than Factory springs and would therefore be less responsive to being lifted by the air bags for a given air pressure.

(BTW, air bags were installed by a PO, I have ZERO documentation on them)
Before.JPG
After.JPG
 
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Brentbba

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Jule said:
(BTW, air bags were installed by a PO, I have ZERO documentation on them)

Ok - I'll cut you some slack. :flipoff2:

I only have the medium OME coils. They replaced the original OEM coils that had about 11 years on them. Result was only about a 3/4 inch gain in height with the new OME coils. Truck does raise some when airbags are fully inflated but not 4 inches.

Since you have zero documentation, Airlift suggests you keep the bag inflated to no less than 10psi IIRC and to check the pressure weekly. I generally keep mine at 15-20psi as they do loose pressure. I'm not anal about checking the pressure weekly, thus the higher daily psi. Max inflation is conflicting. The info I got with my bags says max is 30psi, but I recall also reading info on their website that said 25psi max. I've used 30 w/o incident several times. I've had the bags for 2-3 years now and tow a 3500lb trailer.
 

Moby

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W does full air bag conversions http://www.overthehill4x4.com/Airbag.html and he runs bags on his truck http://www.overthehill4x4.com/images/Suspension/Large/suspension2.jpg I was just down at his shop talking about air bags with him and James on Friday.

This isn't an option for you since you've got coil's but my plan is to convert the rear of my 62 to airoverleaf style airbags(http://www.ridetech.com/productinfo/airoverleaf.asp) with one or two leaves removed (that way I can carry the removes leaves as spares in case there's a problem). If that works out and I convince myself that it can be reliable over time for what I use the truck for then I'll convert to a 4 link and lose the rear leaf springs completely.
 
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Air bag 'Lift' suspension - yes you can!

Ok, I can see this being done with little effort. FYI, I installed a set of stock rear bags in my 94 FZJ80 and put in a set of ford van rear application airbags into the front of my LC to keep the TJM from scraping the ground. Basically what you can do is measure your stock EMU length and diameter (on all 4's perch to perch), and give Air Lift (Lansing Michigan) tech line a call - that's exactly what I did, and they were most helpful. What you could do is put in a set of air lifts that gives you little or no lift in stock trim, but then insert some of Air Lifts molded spacers in the bottom of the spring (BTDT), when you re-pump the bags, you actually get lift. The spacers can be inserted/removed by lifting the respective side of the truck - btdt2. I actually use the spacer at the top, and it is held in by a couple of zip ties (for the last 20k miles), but there is no reason you can't insert them at the bottom of the coil as well to get actual 'lift'. The spacers come in 1.5in plastic that fit perfectly inside the stock FJ spring, and they have a air feed hole in the center of them. If using them on the bottom perch, you can run a couple zip ties or bolt thru the spacers and into the hole in the bottom perch. Probably 5minutes an axle to get as much lift as you desire. If you try to do this with just a longer bag, expect it to not last very long (Air Lift has some technical term for this binding phenom - suffice it to say it will rub a hole in the bag). Min pressure on Air Lift bags is 6psi, max is 35.

HTH

Scott Justusson
SUMOTOY
'94 FZJ80 Air bags x 4
 

Moby

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Walking Eagle said:
What kind of bags are those he's running? Any specs on them? They look about perfet to slip an 80.

Sorry, I don't know exactly what he's running. I imagine that he builds each system to suite the individual needs. Give W or James a call, they're super helpful and do really good work.
 

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