4-link front suspension w/ air bags

["Mad Max"]

Folks,

A bunch of you guys know that over the last year and a half I've been building a '78 Ramcharger, and I wanted to post some of the chassis mods. Granted it's not CTD-powered, but the chassis (though a gasser) is all 1st gen, the axles are Dana 60 front and Dana 70 rear (from my own 93 CTD), and with minor changes everything done to this RC will work on a 1st gen CTD. My own 93 CTD project starts after the RC is complete.

Also, these mods are not diesel conversions, and no 2nd or 3rd gen rig can use them, so, I'm posting here in the 1st gen forum.



First off, the front 4-link and air bags. The entire build-up of my rig is on the Ramcharger Central website, and I'll post the link. These are portions of that thread.



First, you need brackets for the Dana 60 front. A good friend and fellow fab'r Ray own Ram Off Road and made these brackets for me. The front and rear suspension was all designed to match the original leaf spring widths, therefore the bushings and sleeves will fit inside the factory bracketry, if needed.

We used Chevy rear leaf spring bushings - easily available at most 4x4 parts stores.



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To make the brackets, I cut the rough blanks from 1/4" plate steel using a sabresaw and t-shank blades (T123X work fantastic), then Ray put them in his CNC, and out came perfect brackets.



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To make the p-side fit square you have to go 'around' the diff housing, so I had to get creative and it worked great -

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Rear brackets are a simple two-in-one bracket that shares a common wall, and it also boxes the frame in the process - double bonus-



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Control arms were tricky - the lower takes the brunt of the stop and go force plus has to clear the tire, and the upper takes the torque wrap and has to clear the lower edge of the frame, thus the bends as shown. Both arms will be gusseted.



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Tire on ground - note the control arm angle

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Tire at max compression - won't be this high as the shock and airbag won't allow it, but shows the flex potential of the arms

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["Mad Max"]

Air Bags

AIRBAGS



Technically these are air springs - no coils or leafs, just like a semi.

Front bag mounted in place - note the forward and inward lean to match both the control arm arc and single side articulation tilt.



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Upper mount:

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Rear mount:

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rear bag:

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["Mad Max"]

PANHARD BAR:



D-side mount. Angled to match arc with the control arms:

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P-side panhard mount:



Had to drill/tap the spring perch to get one more 9/16 bolt - slick and simple

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So that's been the last 1-2 months of work. The RC is about 1 month from being complete and rolling. I'll post the link to the whole thread shortly. Hope this spurs some ideas in case anyone is looking to convert to air suspension.



The crossover steering conversion and Ram-assist will be another thread.



- M2

 

["Mad Max"]

Shock mounts:

Wanted to follow up with the pics fo the shock mounts, sway bar mounts, and some flex pics. Again, any 1st gen chassis, gas or diesel, can be built to do a system like this. I'm doing it to this 78 RC as practice for my 93 CTD project.



Shocks, RS9000's, front and rear:



Front mounts: Using the front subframe for the upper mount, and the control arm mount for the lower mount. Limiting straps and bump stops will hit first before the shocks reach full travel.



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Rear mounts: In order to get the full 14" of travel as well as provide 'armor' for the airbags I mounted the shock directly behind the bag, and to get the full functionality of the shock I mounted it in the direction of travel, but, it also meant building the upper mount prerunner style, meaning the shock mount will extend about 5" above the floor, and that's with a 3" body lift, fortunately the tower comes up right under the rear seat (bonus).



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- M2

 

["Mad Max"]

Sway bars

Sway bar installs. Rear bar is a 15/16" unit from an '02 Dodge 1-ton Dana 80, and the front bar is a 1-1/8" unit from the rear of a newish Ford 1-ton rear.



Rear mounting was a snap. Ordered 1/2" heims locally, got some grade 8 steel nuts, some tubing, and made the end links 'Uber strong.



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Front mount was tricky. Mounted the bar facing backwards (the truck won't care... ), but had to make the frame mounts to suspens the bar in mid air. Worked great and fits up in there nice and snug:



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- M2

 

["Mad Max"]

Flex

Ordered the limiting straps today based on last night's flex test. These are pics of the rear and front flex shots.



7" up on one side, 7" down on the other = huge rear articulation



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4" up, 7" down = huge front flex. Had to stand on the front hub because the 4-link wanted to act as a torsion bar, which is cool with me as that will add up to a really nice firm ride, and with the weight of the wheel/tire it'll be just right off-road - just the way I want it.



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- M2

 

[Flexiheep]

M2

Since I am sure there are others just as crazy who are interested in bag selection, how did you select your air springs (weight rating, pressure range, travel, etc)? I have looked around and asked questions, but that is the one thing that no one wants to give up. Any info you have would be very welcome.

 

["Mad Max"]

The biggest concern was, in this case, articulation/suspension travel. These bags are the only ones on the market that have 14" of total travel, a lot for a bag, and eash carries 2000lbs weight - perfect for any truck, depending on how much psi. The truck won't raise like a slammed rig, rather you can compensate for a heavy trailer by adding psi. Ride height is right around 13" for the bags.

AiRock sells the bags (Firestone bags):

http://www.offroadonly.com/products/suspension/airock/

The control system is from Air Ride, and is a modified version of one of their existing systems. I used a different compressor than what came with the standard kit, different gauges, etc, and they built me a system and sold it 'complete'.

Should know in a month or so on how it handles - aught to be really sweet on the road, and super strong off road.



- M2

 

[Flexiheep]

Not to second guess you, and for a ramcharger they do yound perfect (and for my 66 Heep). I guess I think they might be a little light for a diesel Ram though. My front end weighs in at 4300 with the whole truck at about 7000, not much extra capacity for a bed full of ceramic tile with those bags... . Pretty sure I don't need 14" of travel under my Cummins though (stock is what 2 up and 4 down), just a lot better street ride . Where did you look for the bag specs, did you just work with AiRock?