S-10 Airbag Installation

This how-to provides basic info for installing the Front bags on 2wd trucks.  It also covers the compressor, tank, line, and wiring information.

Part I:  Compressor & Tank

Depending on which size compressor/tank your choose, you want to find the best placement of your system to maximize cargo space and maintain a neat installation.  I chose to mount mine close together so I could still fit my toolbox in the rear. 

Mounting
The tank and compressor are fastened to the floor by simple nuts and bolts.  Pull up the rug in the rear area and mark the holes on the floor for the tank and compressor, then drill.  Watch out that youre not drilling thru the rear crossmember, or the gas tank!  Once the holes are drilled, cover the floor with the rug and feel for the holes, then drill thru the rug.  Use the supplied hardware for the compressor, and standard nuts/bolts/lockwashers for the tank.

Electrical
It is best to use a 30A Automotive Relay to power the compressor.  This lessens the electrical load on the pressure switch.  The pressure switch simply monitors the pressure of the tank and shuts the compressor off/on according to the factory preset or your setting (if adjustable).  You want to wire the system so that the pressure switch controls the coil on the relay (85/86).  When the pressure switch kicks on, it activates the relay, which in turn powers up the compressor.

Plumbing
Since only my front is done, I only have two lines to route to the front of the truck.  Make sure you use rubber grommets when going thru the floor.  You will probably have to drop your gas tank to get the lines down and out.  Route the line along each side of the frame.  Its pretty easy to find places to fasten the line to on the inside frame rails.  Use zip ties to fasten the line down.  Watch out for heat exposure near the cat and the muffler.  Towards the middle of the truck, the frame is boxed in.  Some people fish the line thru the box, but that seems WAY too difficult.  Instead, I came out of the frame rail and used plastic PVC clips screwed to the bottom of the floor to hold my line in place, then went under the firewall on each side where my valves were waiting!

Valves
I chose 2 valves per wheel and wanted to mount my valves as close to the bag as I could for better speed.  The valves hooked together on each end of the T-fitting.  One side fill, the other dump.  The bottom part of the T goes to the bag.  To create some backpressure to prevent valves sticking, I cut about 6" of airline and connected it to the dump valve.  Note:  Check to see if your valves are directional, the SMC models are.  They say IN on one side of the valve.  This is the side air ENTERS.  Using 2 1.25" U-bolts on each side, I fastened my valves to the inner fender wheels by drilling 4 holes so the U-bolt would mount against the brass T fitting used in my valve setup. 

Switches
Right now I use 2 momentary switches mounted in factory switch spots above the headlight controls.  It looks very neat, almost part of the controls.  3 wires go to each switch - 1 constant 12V, and power to the fill and dump valves.  I used the PWR terminal on the fuse box to get a constant 12V even with the key off. 

Fittings
For a reliable, trouble-free installation, I recommend using all DOT fittings with DOT airbrake line.  Plastic fittings that come in those kits dont last and you end up with leaks and alot of problems.  These brass DOT fittings may seem expensive ($2-$5 each) but consider it worth it in the longrun.  The Push-To-Connect (PTC) fittings are especially nice, just insert the line and push!   That's it!  For threaded connections use Teflon Tape for all connections.  Wrap the tape CLOCKWISE on the thread about 3 times to get a leak-free seal.

Fitting List 1 - 3/8 pipe 1/2 line PTC Fittings 2 - 1/4 to 3/8 Bushings 3 - 3/8 Brass T 4 - 3/8 Pipe to 1/2 Line PTC 90 Elbow 5 - 3/8 Brass 4-way 6 - 3/8 Threaded Couplings Note:  Quantities may vary depending on installation.

Once you get this far, fill your tank, and adjust your pressure switch to the desired pressure.  Check for any leaks at the tank and valve locations.  Press the switches to see if the valves click.  Your fill valves should make the infamous 'PSSSSHT' noise.  If all is well, you can start installing the bags.

This installation covers the install once the coil springs are removed.  If you would like to see some pictures that may help you remove the factory coils, check out the 2wd Drop How-To.

For my install, I use the front upper and lower brackets from Suicidedoors.com.  These brackets are totally bolt in and fit great and are also very affordable.  They feature bolt patterns for a variety of bag styles, including Firestone 2500 and 2600, and have large dual port holes. 

I used 2600 bags with single 3/8" ports for the front.  As you probably have already read, you need to eyebrow the spring pocket to accomodate the larger sized bags.  From what I understand, using 2500# bags require little or no spring pocket modification. 

First, grind out the inner lip on the spring pocket.  This needs to be removed and deburred of any sharp edges that could potentially rub the bag and pop it.  It is extremely important to make sure metal does NOT come into contact with any part of the bag at any range of motion to ensure a trouble-free installation.

The top bracket uses the stock shock absorber mounting hole with a washer and nut on top to hold it in place.  A hole must be drilled as necessary to feed the airline to the valve.  Mount the top bracket in place and mark where the airline will exit the bag.  Drill a hole about 1/8" bigger than your diameter of airline.  Now remove the top cup and mount the bag to it, then put back into place to get ready to start figuring out what needs to be cut.  The bottom bracket bolts directly to the lower control arm via the stock shock holes.  Remove the 2 clips to expose the holes.  The cup will only fit in one way.  Once in place, tighten the nuts to secure the cup firmly.

Place a jack under the lower control arm and begin to raise the suspension.  Make sure the bag is centered on the lower cup.When the bag is deflated it will be at its widest diameter.  Mark approximately where the spring pocket needs to be cut..  Remove the top cup (no need to remove the lower) and begin cutting.  Its probably easiest to use a whizzer wheel.  I wouldn't recommend a torch unless you are good at using one.  Note in the picture below the hole that was drilled for the airline.

Spring Pocket Eyebrowed

Once you have the majority of metal cut out, replace the top cup with the bag mounted to it and give it another test.  If it rubs or comes close to any point of the bag, remove and cut more.  Remember, the bag will stretch over time, so you want to make sure you have enough clearance for the future.  What may clear today may not in 2 months.  I'd say if you can stick your finger in, you are good.

Test Fit for Clearance

Once you are confident that you are totally clear from contact with the frame/spring pocket, connect your airline, run it thru the hole you previously drilled, fasten lower bag bolt (3/8"-16x3/4") thru the cup into the bag with a lock washer, and tighten the top mount.

Connect the airline to the bottom of the brass T-fitting into your valves.  If you are running a gauge for your bag pressure cut the line from the bag to the valve and install another T, with your 1/4" gauge line going out.

If you'd like to use shocks, you need to get a Shock Relocation Kit.  Again, I used the kit from suicidedoors.com.  It comes with a 2 brackets and 2 carriage type bolts.  I used Gabriel Gas Shocks from a Ford Ranger.  These give me the full range of motion, from 0psi to full lift.  The bracket is welded to the frame and is reinforced with some flat bar on the side to stop it from flexing, and a hole is drilled on the lower control arm approximately in the middle.  The shocks really help stop the bounciness from the bags flexing.  Some people dont use them, but I wanted as nice a ride as possible.

Stay Tuned for the Rear!