Airbag Man

Heavy Duty Airbag Kit

LandCruiser 200

Step-by-Step installation

When choosing suspension for your vehicle, there is often a tradeoff between handling and performance when laden versus unladen.

If you fit rear springs that deliver comfort and a correct ride height when the vehicle is unladen, then it will result in sagging when you load up for a trip. Conversely, if you fit heavier springs to cope with high loads, then it will mean a harsh ride and tail-high vehicle once you're unladen between trips.

But there is a solution.

Helper airbags

Polyurethane 'helper' airbags, which are installed within the rear coil springs, can solve this problem.

When the vehicle is unladen, the airbags are set to minimal air pressure. But when loaded for a trip or towing a caravan or camper-trailer, the pressure is increased in the bags allowing the vehicle to carry higher loads while maintaining the correct ride height.

Airbag Man High Pressure Airbag Kit

Regular readers will remember that I installed a set of Firestone Coil-Rite helper airbags into the 200 back in 2015. I'm now replacing those bags and the inflation system with a superior setup consisting of:

  • An Airbag Man CR5052HP heavy duty airbag kit
  • An Airbag Man AC1030D air control kit
  • A pillar pod (mounted on the 'A' pillar) to mount the gauge.
  • Two push on-off dash switches for fog and driving lights (The new paddle switches now fit where the lighting switches once were).

I'm replacing the previous setup for a number of reasons:

  • I'm having a GVM increase approved via an engineer, and the heavy duty kit allows higher bag pressure and therefore load carrying capacity over the standard Firestone kit.
  • I had some issues with airlines pulling out of the standard Firestone bags under certain suspension travel situations. The Airbag Man kit includes superior protection for the airlines where they travel through the bumpstops and into the tops of the bags, plus adds vehicle-specific protectors which sit between the bag and bumpstops. These features should solve this problem.
  • Having the ability to inflate and monitor the bags from the driver's seat adds convenience, and also improves safety in case of a leak or damage in the system.
  • The heavy duty kit includes unique high strength fabric sleeves which (in addition to allowing higher pressures) also add protection to the bags, making them more resistant to puncture and damage.

Pros and Cons of fitting helper airbags

The main benefit of fitting helper airbags instead of different coil springs is that they allow for variable loads. You don't have to choose between having a vehicle that sits high and rides poorly when unladen, or one that sags and bottoms-out when laden. You can have the best of both worlds.

But nothing is without some compromise. The airbags do reduce suspension travel slightly, particularly when they are inflated. This is more a concern for vehicles set up for hardcore weekend 4WDing than touring vehicles, but still something to be aware of.

While standard Firestone and PolyAir bags are very durable, they're not as strong as a steel spring and are therefore more susceptible to damage. In the case of failure you would lose the benefit of the bags, leaving you with a saggy rear end....and nobody wants that! The Airbag Man heavy duty kit I'm installing overcomes this limitation through the addition of unique fabric sleeves around the bags to provide greater protection.






Selecting and buying airbags

Airbag Man offers 'standard' and 'high pressure' kits in three different heights, depending on your vehicle setup and load carrying requirements:

  • Standard height, 30psi pressure: CR5051 kit.
  • Standard height, 60psi pressure: CR5051HP kit.
  • 20-30mm raised height, 30psi pressure: CR5052 kit.
  • 20-30mm raised height, 60psi pressure: CR5052HP kit.
  • 40-50mm raised height, 30psi pressure: CR5151 kit.
  • 40-50mm raised height, 60psi pressure: CR5151HP kit.

Most aftermarket suspension kits for the 200 (Including my Tough Dog system) raise the rear around 20-30mm, so the 5052 kits are the most suitable.

The choice between standard and high pressure versions depends on your needs. The High Pressure bags include fabric sleeves to enable higher load capacity and improved protection from damage. Because I'm about to undertake a GVM upgrade, and I travel in rough and remote terrain, the high pressure versions are ideal. However if you plan on sticking to asphalt roads and only require minimal load carrying help, then the standard versions may suit you better. The heavy duty airbags can be inflated up to 60psi (415kPa), depending on the load. The standard versions can be inflated up to 30psi (240kPa). You must keep a minimum of 5psi (35kPa) in the bags at all times to prevent them being pinched and damaged by the coil springs.

Depending on your needs, there are a number of inflation and monitoring options available for the airbags. The standard kits include basic 'tyre' inflation valves, allowing manual inflation and pressure setting at a service station. However, because I already have an on board air compressor and reservoir, I'll be hooking my airbags up to that via an Airbag Man AC1030D air control kit. This kit includes dual inflation paddles which I'll be locating on the dash. They fit perfectly in the enlarged holes I previously created for some Carling fog and driving light switches, so I'll be placing the paddles in those holes and taking the opportunity to replace the Carling switches with some of the great new factory-look switches which are now available for the 200. The digital pressure gauge will be installed into a single-gauge pod which replaces the grey plastic trim on the A pillar. If you want to install additional gauges (e.g. voltage or EGT), there are also twin-gauge pods available. Ensure you choose the correct trim colour (grey or beige) for your vehicle.



IMPORTANT

The "Installation" section should not be taken as instructions. It is simply a documenting of the procedure I followed for my own installation. No warranty is provided as to the accuracy of the information, and/or whether it applies in your situation or to your vehicle. If you're not qualified and/or don't have the correct equipment, get the airbags fitted professionally.

  • There are potentially lethal dangers involved during the installation from falling vehicles or components and/or component or equipment failures.
  • There are potentially lethal dangers resulting from failure due to improper installation.
  • There is the potential for expensive vehicle and/or suspension damage from improper installation.

If you undertake your own suspension installation, you do so entirely at your own risk.

Equipment required 

Installation

Click images to enlarge

Step 1 - Prepare the vehicle:

  • If your 200 has KDSS, then release the two shutter valves 3 turns.
  • Raise the vehicle so the rear wheels are off the ground, and support it on chassis stands. Leave the jack under the diff centre, so you can raise and lower the axle as required during the installation.
  • Remove both rear wheels, and place them under the chassis for extra safety when you're working under the vehicle.
  • With the jack taking the weight of the axle, remove the bottom mounting of both rear shocks, and the sway bar brackets on each side.
  • Remove the diff breather hose and remove the bolt holding the brake line bracket to the axle, just above the differential. This will allow the axle to drop without straining the breather/brake lines.
  • Lower the axle on the jack until the springs are loose.
  • Remove the springs from each side, complete with the internal bump stops.

NEVER work under a vehicle that is supported by a jack (or jacks) alone.




Step 2 - Prepare the components:

  • Place the bumpstops in a vice, and cut four segments off each one, so only the top segment remains. Ensure the cut surface is smooth and free from sharp edges.
  • Drill out the hole in the centre of the bumpstops to approximately 35mm in size. A quality holesaw is typically the best tool for the job. Ensure the enlarged hole is smooth and burr-free.
  • Fit one of the the elasticised ends of the high pressure sleeves over the airbag, and position it so the tapered ends sit neatly and evenly over the upper and lower shoulders of the airbag as shown. Repeat for the second airbag.
  • Install the airbag into the coil spring, with the air inlet valve at the top.
  • Remove the rear sill/scuff trim by levering out the small round screw cover, and removing the retailing bolt. The trim then unclips by pulling upwards. Then cut an 'X' into the rubber grommet as shown.
  • Remove the driver's plastic kick panel. It's removed by unscrewing the plastic nut near the accelerator pedal, then pulling towards the centre of the vehicle to release the plastic clips.
  • Remove the driver's sill/scuff trim. It unclips by lifting upwards.
  • Remove the B pillar lower trim. It unclips by pulling towards the centre of the vehicle.
  • Enlarge two of the blank factory switch plates to accept the paddle switches. You can do this (carefully) with a sharp knife.




Step 3 - Running the airlines:

Where and how you run the airlines will totally depend on what sort of inflation system you'll be using (e.g. air control kit, or basic tyre inflation valves). This guide will assume you're installing the same setup as me.

  • Remove the protective split tubing from the airline that came with the airbag kit, and refit it to the two longer black airlines that came with the air control kit.
  • Place a band of electrical tape onto each end of one of the airlines, and use that one for the RIGHT side of the vehicle. This will help avoid confusion during later connections.
  • Start running each airline with the protected end i.e. the end with the split tubing) at the top spring seat. I suggest leaving around 300mm of slack hanging down from each spring seat.
  • Run the left side airline across the crossmember to meet the other airline, then run both airlines forward along the right side chassis rail. Ensure the lines are regularly secured with cable ties, and they are kept away from sharp edges and hot objects (e.g. the exhaust).
  • Run the airlines from the chassis rail, up through the grommet, then along the sill into the driver's footwell. You can secure the airlines in the factory clips, and seal the hole in the grommet with some silicone.

Step 4 - Run the airline from the compressor:

  • Using some tape, attach the red supply line that came with the air control kit to a rigid piece of wire. You can then push the rigid wire through the factory wiring grommet into the engine bay. The grommet is located behind the dash above the accelerator pedal.
  • Pull the air line through to your compressor connection/manifold, which in my case is located on the passenger side firewall.
  • Connect the airline to the compressor/manifold using the supplied fitting(s), and then secure the airline away from sharp/hot objects using cable ties.



Step 5 - Guage/Pod and electrical connections:

  • Extend the three wires on the gauge so they will be long enough to reach from the gauge location (in the pillar pod) to the required connection points. The three wires connect to:
    • Red: Connect to Accessory/Ignition power (I will be connecting this wire to my existing air compressor dash switch).
    • Purple: Connect to dash illumination power. This wire dims the gauge when the headlights are switched on. I'll be connecting it to an existing dash switch.
    • Black: Connect to a good chassis/body earth point.
  • Remove the grab handle on the driver's side 'A' pillar, by levering out the screw covers, removing the screws, then unclipping the handle.
  • Remove the plastic 'A' pillar trim piece by lifting out of position. Use extreme caution not to damage or interfere with the side curtain airbag or wiring.
  • Insert the Airbag Man digital gauge into the pillar pod and secure with the supplied bracket and screws, ensuring it's mounted with the correct orientation.
  • Connect the two supplied pressure sensor wires to the back of the gauge.
  • Run all the wiring from the pod down between the A pillar and the dash.
  • Install the new pillar trim into place by first pushing the lower edge into position, then aligning the trim to the mounting holes for the grab handle. Refit the grab handle using the original bolts and trim covers. Again, use extreme caution not to damage or interfere with the side curtain airbag or wiring.

Step 6 - Connecting and testing the airlines:

  • Always cut the airlines with a dedicated airline cutting tool or a sharp knife. Do not use pliers/scissors etc, or the connections are likely to leak.
  • Trim the airlines for each airbag, ensuring there is sufficient slack to allow for full suspension travel. You can then connect the airlines to the airbags, running them through the cut-down bumpstops and also the black ???, with the taper in the centre hole sitting against the airbag. Don't replace the spring/airbag assemblies into the vehicle yet.
  • Pre-cut some small pieces of airline to begin connecting the paddle switches.
  • Using the red supply line, connect the inlet valves of each paddle switch together, using one of the supplied junctions (Y piece) as shown in the photo.
  • Make the connections to the outlets of the paddle switches as shown. It looks complicated, but is quite simple. Connect a black airline segment to each paddle switch, then to a junction. Connect a pressure sensor to one side of each junction (the other side will connect to an airbag).
  • Thread the red supply airline and the two black airlines (running to the airbags), plus the pressure sensor wires out through the hole in the dash where the paddle switches are to be mounted, and connect all the airlines and pressure wires as shown in the photo. Leave the paddle switches hanging out of the dash hole.
  • Turn on the compressor, and pressurise the airbags to their maximum 60psi.
  • Spray all the airline connections with a soapy water solution to check for air leaks. If any leaks are present, remove the airline from the connection, re-cut it, re-attach and check again for leaks.
  • As carefully and neatly as possible, feed the airlines and wiring back through the hole into the dash until the paddle switches sit properly in the dash. You should then tidy and secure the airlines behind the dash with cable ties, ensuring there are no kinks in the lines.

Step 7 - Install the paddle switches, restore trim panels:

  • As carefully and neatly as possible, feed the airlines and wiring back through the hole into the dash until the paddle switches sit properly in the dash. You should then tidy and secure the airlines behind the dash with cable ties, ensuring there are no kinks in the lines.
  • Refit the B pillar trim panel by pushing it back into place (it's secured by plastic clips) into the B pillar.
  • Refit the driver's kick panel, by clicking it into place and refitting the plastic hand-nut.
  • Refit the front sill/scuff trim by clipping it back into place.
  • Refit the rear sill/scuff trim panel by clipping it into place, then replacing the retaining screw, then replacing the round screw cover.
  • You can find the new factory-fit dash switches here (fog) and here (driving).

Step 8 - Refit the coil/airbags into the vehicle:

  • With the airbag about half way into the coil spring, slide the black support collar down the airline so it sits on top of the airbag.
  • Install the cut-down bumpstop into the top of the coil spring.
  • Reposition the top of the coil spring into position, taking care to feed the airline up through the chassis spring support as you do so. Ensure there is sufficient excess airline to allow full suspension movement.
  • With the top of the airbag in place, position the bottom of the coil spring on the axle housing. You may have to rotate the spring to align it correctly.
  • Lift the axle using the jack, and reattach the lower shock mounts, the sway bar connectors, the diff breather hose and the brake line mounting bracket.
  • Re-Check the position of the airbag and sleeve, and manipulate them if required.
  • Refit the wheels and lower the vehicle back to the ground.
  • Re-tighten the KDSS shutter valves if applicable.

Step 9 - Finishing:

  • Place the provided wallet in the glovebox with the owners manual, for future reference.
  • Affix the supplied warning sticker to the dashboard.

Comments / Q&A