I carry a camper on my 2015 F350 DRW 2WD. The camper weighs about 3300 empty, sagging the suspension about 3". That gets it level or a little past level. With full tanks, people, and supplies for a week it will be down another 1/2" or more. Looking at airbags they are all pretty much the same, mounting under the frame and over the axle.

A 2WD has no axle blocks so the minimum room of all the variations. You start with about 7.5" from the turned down flange on the frame to the top of the axle. Subtract 2" to get closer to level from sag, add a couple of mounts, now I have less than 4". Airbags have a collapsed height of about 3", so I have less than an inch to bottom the bag - of course the factory bump stop is gone, replaced by the bag, which you are not supposed to bottom. I just trial fit the Hellwig system as it looked like the mounts took less room, but ended up with only 3 1/4" jounce travel at full empty ride height, so maybe 1/4" jounce travel with the truck level, or 1 1/4" travel at my ideal ride height of 1" rear high. The stock suspension still has 2 1/4" jounce travel at 2" sag, to a very soft bump stop that you could get into 2" or so before you really noticed.

When you talk to the tech support of the airbag companies they are not very familiar with this problem, I think most installs are on 4WD where you would have at least another 2".

The only solutions that come to mind are lift the truck (not interested), do an outside the frame installation (not much more room there and it's kind of dodgy), install the kit and run the bags to maintain unloaded height (camper going downhill and bags supporting its entire weight), or trashcan the whole suspension and go with a true airbag conversion.

If I remove the overload spring and its block, there is more room outside the frame over the spring to at least keep some travel. I would still have to have the bracketry involved in those kits which is in general poorly engineered. On my old '99 7.3L I modified an outside the frame Firestone kit to get as much travel as possible, but it would still bottom (and top out) occasionally. We're talking service station ramps and the like, not offroading.

I would go to a pure air suspension but there aren't many being offered anymore - Kelderman and Autoflex are about it these days. Are there any others? Any other airbag kits that I don't know about? Hellwig, Airlift, Firestone, Pacbrake, a lot of minor variations on the latter two. Given the amount of room available, I think these guys have done what can be done.

 

Did you go to airlift and Firestone web sites and search for your truck configuration? I can't believe that they don't have kits for 2wd trucks.

I'll see what I find....

 

Oh, they make kits they say will fit. And you can actually squeeze the bag into the space available, so long as you don't mind close to zero suspension travel. With the truck level, there is 4 1/2" of space to fit the mounts, bag, and jounce travel. Ford just didn't leave enough space.

I'm not really blaming the bag companies, the 2WD isn't a priority and I gather there aren't that many of them, so they list it for completeness. The only way it works is if you pump the bag up to at least empty ride height, which means the springs aren't carrying any of the load. But I ask in case someone has thought of something I haven't.

 

Ok. I've been running air bags since 2007 and the way that I use them varies with every drive I take. In your case, I feel confident that

1. The bags are durable enough to take the punishment of your set up, even with the tight clearance.

2. The psi you would need to gain 1-1.5" inches of height when loaded would be in the 15-25psi range. I do this a lot, I can add 60psi and get my axle as far apart from the aux. spring as if the truck had no load. I don't. I usually leave about 1" of travel in there before the aux spring would engage.

They are so versatile, you can do anything. Use 10psi and let them just be there for swells/bridge expansions. They wouldn't really do anything unless needed.

Truthfully, I would prefer the springs be in a tight spot. The flatter the bladder is, the more efficient it will work under load. You might only need 5psi....

 

Yes but: the manufacturer of the kit and the bag both say don't bottom the bag, you will damage it and void your warrantee. It turns out you can also bend the mounts (I happen to know ). You have a 4x4 so it is 3" or so higher to start with, 3" more space to put the bag. That makes all the difference. I have put airbags on 5 of my trucks now going back to 1990, so I am familiar with what they can do, if they can be set up right. There just doesn't appear to be enough room on the 2WD.

 

I found this same issue when I traded the bags over from my 11' 250 4x4 to the 16 4x2 350 srw. The mounts do fit, but your right. Very little travel. I cut the an inch or so of the top and bottom mounts. Down to only the last holes. This gave me lots of space and more travel than I had with the larger blocks on the 4x4. I believe I have pics already posted. Let me see if I can find the page.

 

Take a look at near the bottom of the first(and only) page. It was only necessary to cut the bottom brackets as the top fit around the axle. Used a jigsaw and grinder. When it all fit the way I liked, repainted. No more bottoming out.

https://www.ford-trucks.com/forums/1...load-pads.html

 

Nice. Back in 2008 I strengthened the bottom brackets by welding some solid supports to them. I know we shouldn't have to, but if willing, things can be made right.

 

I did just that on a Firestone kit I bought for my '99, still didn't get near enough jounce travel, sold them on Craigslist. The Hellwig kit has a lower mount that is thinner still, but there still isn't enough room. You sig says CC SRW - how much of a block is there between the axle tube proper and the leaf spring pack? On mine, there is no block, just the perch welded onto the axle tube and it stands about 3/4" above the axle tube.

I have the equipment to fabricate the brackets from scratch, I just don't see the room to do it.

 

Finally got a call back from Kelderman, they do not make a 4 link suspension for this truck, so that leaves only Autoflex, or some kind of airbag helper.

 

There should be enough room to get them to fit. These are the blocks I build for air lift dominator bag which are bigger than the short travel ones in air lift or firestone kits. Note the bag surface is only about 1" from the top of the block. Since 2wd have no block, mount the bag as low/close as possible to the axle tube and it should be good.


Option B is to add a 1" rear block for additional room. The manufactures list compressed height of the bags, so with a tap measure you can see what will fit. good luck.

 

My blocks are about an inch. Not really blocks at all. I just went out a snapped a few pics for you. Let me know if you need more or want me to actually pull a tape.

 

Another photo showing reduced height bracket, drivers side. 5psi empty bed

 

Passenger side. 5psi empty bed. More travel than I had on the 4x4 250 with brackets at lowest notch.

 

Passenger side blocks. Better photo