When is a 1-ton truck not a 1-ton truck? When you put a 5/7 drop kit on it and do nothing to restore the load-carrying capability that you lost with the flip kit or de-arched leaf springs. That was the case with this '99 Chevy C3500 model sport truck, which looks like it has been trapped in a time machine for the last decade. This Silverado, which sports a timeless look with its dropped stance, 60-series rubber surrounding Alcoa rims, and a full-length shell, has all the payload capacity of a stock Toyota mini-truck.
Even with a healthy Bell Tech C-notch and a professionally installed lowered suspension, a few hundred pounds tossed into the bed would have this truck bottoming out over every dip and bump in the road. The suspension was also so mushy that on flat ground the Caddy-like ride felt good, but over the rough stuff the '60s-Bel-Air-floating-over-a-set-of-railroad-tracks feeling was not. Something had to be done.
We looked to Air Ride Technologies to inject a little psi life back into this truck's rear suspension so that it could act like a truck when necessary, and roll smoothly down Southern California's freeways every other day. The solution came in the form of the company's ARK4900 "air over leaf kit," which positions a pair of 255C-model double convoluted air springs directly behind the axle and on top of the leaf springs. We also installed an ARC1600 "two-way compressor system," which gave us the ability to alter the air pressure within the 'bags on the fly.
We took our truck to Industrial Motoring in Placentia, California to have the kit professionally installed. The whole deal took less than eight hours and was a fairly painless operation. The system required zero fabrication on our part and once installed, offered up a ride we could tailor to our liking and also boosted the truck's payload capacity. In short, we got a better-handling vehicle that we could once again refer to as a real truck. Check it out.
What's In The Box?
The ARK4900 comes with upper and lower mounts, airbags and Grade 5 mounting hardware. The ARC1600 completes the install with two-way paddle controls, a dual-needle air gauge, and a stout compressor that will fill both 'bags in minutes. No reserve air tank is necessary with this kit because of the small volume of the pair of 'bags and 1/4-inch diameter air lines.
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 1a.The great thing about the...  1a.The great thing about the ARK4900 kit is that it bolts directly onto the existing Bell Tech "super c" notch kit. |  1b.After supporting the chassis...  1b.After supporting the chassis at both ends and on both sides of the C-notch, all we had to do was remove the four rear bolts from the notch and bolt our new 'bag mount to the outside of it. |  2.There are a couple of considerations...  2.There are a couple of considerations you must make before you go further. First off, you've got to establish how low your truck is because that will determine whether the upper mount goes flange-up or flange-down. Also, the suspension travel when the vehicle is off the ground is greater than the 'bags will allow once they are installed, so you'll need a way to jack up the rear axle in order to connect the airbags to the upper and lower mounts. |
 3.The lower bag mounts sandwich...  3.The lower bag mounts sandwich between the U-bolt mounting plate and leaf spring pack so it's necessary to loosen up the U-bolts. |  4a.There are several positions...  4a.There are several positions to attach the 'bags to the lower mounts. |  4b.After staring at the position...  4b.After staring at the position of the upper mounts for a bit, we decided the 'bags needed to be bolted to the lower mounts as far to the rear of the truck as possible. |
 5.This is what you'll be looking...  5.This is what you'll be looking at when you put the 'bag in the wrong spot on the lower mount. There's no way to bolt the 'bag to the upper mount without twisting it backward, which is bad for the 'bag. |  6a.Once you've got the 'bags...  6a.Once you've got the 'bags positioned properly, you can jack up the rear axle until the 'bags are close enough to the upper mounts to bolt in place. |  6b.Should you ever need to...  6b.Should you ever need to have work performed on the truck that requires a chassis lift, you'll want to disconnect the 'bags from the upper mounts prior to lifting it into the air. Failure to do so will stretch the 'bags out when the suspension cycles downward, which could tear the 'bags apart. |
 1a.With the rear suspension...  1a.With the rear suspension properly outfitted, we moved on to adding our in-cab control system. The best place to put the paddle controls is in the center console where they are hidden from view, and where we're not likely to bump into it. We unbolted the console from the floor of the truck and then drilled a hole through the lower portion of the console insert, right up front. This allowed us to bolt the controls just below the lid hinge and route our wiring and hoses through the console where no one could see them. | 
1b. |  2a.Next, we picked a spot...  2a.Next, we picked a spot in the transmission tunnel to drill a 1-inch hole through. |
 2b.We then installed a plastic...  2b.We then installed a plastic grommet into the hole to prevent the sheetmetal from chafing the hoses and wiring we routed through the hole. |  3.The hoses and wiring were...  3.The hoses and wiring were cleanly routed to the onboard air compressor and airbags using rubber-coated, Adel-type clamps to hold them in place. The clamps were bolted to the bottom of the stock center console mounting bolts. The gap in the plastic grommet was then coated in silicone sealer to prevent moisture from entering the cab of the truck. |  4.Our Thomas 215 air compressor...  4.Our Thomas 215 air compressor was bolted to the inside of the driver-side framerail, just below the rear of the cab, using an existing hole in the rail. We only had to drill one additional hole and then connect the wiring and supply hose to complete the install. We also routed a pair of air hoses from the paddle control to the rear airbags at this time. |
 5a.After grounding the control...  5a.After grounding the control gauges, we only had to connect the positive lead from the gauges to a 12-volt illumination wire at the back of the truck's dimmer switch. We ran the wiring from the console, under the carpet above the tranny tunnel, and then up the rear of the dash until it reached the dimmer switch. |  5b.The gauge wiring was then...  5b.The gauge wiring was then simply tapped into the brown wire at the back of the switch. |  LOWERED 6.With the system...  LOWERED
6.With the system fully operational, you can easily see the amount of usable suspension travel we gained by inflating the rear 'bags. |
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The Final Word
This system cures the three main gripes we have with lowered 1-ton sport trucks. First off, they tend to lean toward the driver's side. Since this system offers independent control of the air pressure in both 'bags, that's easily fixed. Second, this truck can now carry a heavy load and tow a trailer without bottoming out. As little as 30 psi in the rear 'bags carries an additional 300 pounds of cargo with ease, and the system is capable of forcing well over 100 psi into the 'bags for hauling really heavy stuff. Third, this truck rides and handles beautifully now. With only atmospheric pressure (14.7) in the 'bags, we noticed a firmer feel in the rear suspension right away. Push another 10 psi into the 'bags and the dualie exhibited less leaning into the corners and the mushy feeling was gone from the suspension. The only negative we could find with this system was that we'll now have to unbolt the 'bags from the upper mounts to jack up the chassis off the ground.