Option for keeping air suspension after coil spring conversion.

[Couve Cruiser]

I thought I'd post the mod I did to keep air suspension functionality after I switched to coils. I originally tried the Airlift bags that go inside the springs, which has been posted on this forum by another member. I wasn't content with this setup since It mostly just increases the coils resistance to compression to prevent sagging under increased load, but doesn't provide much vertical lift. In fact, not enough lift to trigger the sensors to stop the compressor. My solution was to find some double bellows air springs that were small enough diameter to fit in place of the axle bump stop that sits outboard of the coil spring, but still had significant vertical lift, over 8" from full compression to full extension, and has a built in internal bump stop. The bags are made in the USA by Slam Specialties. I researched quite a bit, including looking through the whole firestone air spring catalogue, and was unable to find any other air springs comparable to these. For locating the bottom of the air spring I mounted a cradle that allows the air spring to lift away from the axle if wheel travel exceeds the extended length of the spring. I plan on using the oem compressor and switch. In addition, I've installed wiring and switches to manually operate the air suspension compressor and solenoids to give me the ability to o considerably higher than the factory high setting would allow. I had to do a bit of fabrication and combining of various mounting hardware I pieced together through research. Not sure how well this will work for others, but figured the info might be useful to some. I'll post a parts list and some pictures below. feel free to ask any questions.

Heavy Duty Leaf Spring U Bolt Kit,1/2" Round Suspension U-Bolts 6.5" Long,2 Pack https://a.co/d/2fe3l3n

Slam Specialties SS-6 Air Bags Springs Custom Suspension 2 Pack Amazon.com - https://a.co/d/gQpGmAZ

TORQUE Airbag Air Bag Spring Cradle for Air Bags Suspension Kit, Fits all 6" Diameter Convoluted Air Bags, Fits Air Lift Firestone Torque and all other brands (Replaces Daystar KU09140BK) (TR3004) Amazon.com - https://a.co/d/dyrFnxj

Rear Weld On Lower Axle Air Bag Mounting Brackets For Air Ride Suspension Amazon.com - https://a.co/d/9vCZ5Pq

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[Rednexus]

Quite an interesting and novel setup!

Since the airbag basically replaced the bump stops, is the bottom of the bag a "soft" rubber material? I would not mind adding a set of aux bags to my rig for towing to get a bit more stiffness and maybe skip a WDH, but the would obviously want to keep bump stop function (my rig has progressive DuroBumps which are really, really nice). If bump stops are integrated into the bag it would seem to be more versatile than a normal bump stop-only setup, as long as it does not impede rear flex.

 

[Couve Cruiser]

Quite an interesting and novel setup!

Since the airbag basically replaced the bump stops, is the bottom of the bag a "soft" rubber material? I would not mind adding a set of aux bags to my rig for towing to get a bit more stiffness and maybe skip a WDH, but the would obviously want to keep bump stop function (my rig has progressive DuroBumps which are really, really nice). If bump stops are integrated into the bag it would seem to be more versatile than a normal bump stop-only setup, as long as it does not impede rear flex.

Thanks for the reply. The bottom and top plate are both a hard composite material of some type. I think with any air pressure, the vast majority of the time the bottom of the bag will be firmly in contact with the cradle. I only envision the bag lifting out of the cradle during serious articulation. I do have some adhesive rubber sheet i plan on applying to the bottom plate to soften contact between the spring and cradle. Not quite sure if that addressed your question. Some reduction of rear flex is possible. I haven't really done much testing of the setup yet. I should've mentioned in the initial post that my GX is lifted 2.5" in the rear, and the setup will likely only fit on a lifted GX. Though the setup could be installed in a stock height GX as a means of lifting it, provided sufficient air is kept in the bag to maintain lifted height. Rear flex probably wasn't my top consideration, though I think I'll maintain most of my flex, especially since a have a manual override switch for the gate solenoid that controls air flow between the left and right air spring. If the solenoid is opened in really uneven terrain, it should allow the compressed bag to push out it's air and transfer it to the opposite bag and vice versa. I plan on doing some testing of the suspension travel and posting some pics of the results, hopefully fairly soon. I also plan on installing some 1/8" reinforcement plate between the top plate of the air spring and the frame. In my use case, I don't envision much force being at play there most of the time, just when I use the full height of the springs to clear an obstacle or some such.