When you own a 4X4 store you can be excused for having a vehicle that has all the fruit on it. But a lot of the time there is more bling than zing as far as setting up a good looking vehicle.
This feature was originally published in 4x4 Australia’s May 2009 issue
Nothing could be further from the truth when it comes to this well set-up and practical 4.2-litre diesel Patrol that Todd Shearer of Southern Suspension and 4X4 Centre in Esperance, WA, has built. While there’s a story or two in the list of engine mods and good-looking additions, what really caught my attention was that this rig is completely suspended on air.
Now, you can easily add air bags to a leaf-spring or coil-spring vehicle to help carry the load and there are a number of variants available.
In the past we’ve tested a set of Firestone airbags on a heavily loaded LandCruiser cab-chassis and were very impressed. But, with a coil-spring vehicle you can do more than that, as you have the choice of removing the coils completely and replacing them with air springs. That’s what Todd has done.
Firestone produces a wide range of bellows capable of carrying loads of anything between 40 and 40,000kg. Air springs dominate the heavy vehicle industry and are now becoming much more popular in lighter vehicles, 4X4s, caravans and mobile homes.
For the uninitiated, air springs are, at their simplest, a heavy-duty bag (or bellows) manufactured from a tough rubber and fabric material. Carefully designed, these bellows, in the case of Firestone airbags, come as a ‘convoluted’ or a ‘sleeve-style’ bag, both of which contain a column of compressed air. The rubber bellows themselves do not support the load – the column of air does this when the air bag is inflated according to the load that is being carried.
4x4 Video: Airbag Man wireless on-board air supply kit
The airbag or bellow itself is the heart of the air spring. It includes at least four layers of material incorporating an inner layer, two plies of cord-reinforced fabric and an outer layer.
At the top of the airbag is a bead plate, which is permanently crimped onto the bellows at the factory, thereby allowing the complete assembly to be leak tested prior to shipment. Two studs on the bead plate allow the unit to be mounted to the vehicle while one of the studs doubles as an air-hose fitting.
Attached to the base of the airbag is an aluminium, steel or fibre reinforced plastic piston assembly which also provides the lower mounting arrangement for the spring to the vehicle axle.
Inside the bellows, and connected directly to the piston of the air spring, is a solid moulded rubber, fail-safe bump stop to prevent excessive damage to the vehicle or the suspension in the case of a sudden air-pressure loss.
When used to replace metal springs, the big advantages are that air springs offer a softer ride and they isolate the vehicle from much of the shock, harshness and vibration from the road or track surface.
In addition, the air springs can provide variable height adjustment. The vehicle can be lifted or lowered for easier entry or exit when stationary, a lower ride height can be selected for fast bitumen roads, or a higher ride selected for driving on rough bush tracks. In the case of Todd’s Patrol, a set of Firestone airbags were supplied by WA Air Springs in Welshpool, Perth.
There are dozens of different kits available for anything from Musso Sports to Jeep Wranglers and Land Rovers to all models of LandCruisers, Ford F-Series trucks and smaller Japanese one-tonne utes. In the case of the Patrol, the kit provides a lift of 25-50mm above standard.
On Todd’s Patrol, the air supply hoses were initially routed to a handy spot on the rear bumper and front bullbar, so he had to stop and set up the air compressor to adjust the pressure before continuing. Some aftermarket shock absorbers were fitted but the ride and the flexibility of the system left a bit to be desired.
An in-car control system was fitted with four paddle switches and two dual-needle gauges. It’s mounted behind the extra glovebox area that hides behind the dash of Patrols not fitted with SRS passenger airbags – but you can mount them wherever you want.
This in-car control system allows the air pressure and ride height to be separately adjusted at each corner of the vehicle while on the move. It also allows the vehicle to be levelled when standing still, which is handy if you have a rooftop tent and the ground is uneven. There are a multitude of available air control system options but all the brackets required were custom made for Todd’s Patrol.
The front air springs have a smaller volume airbag than the rears and the ride seemed a bit harsh to Todd, so he fitted a quarter-gallon (1.14 litres) accumulator tank for each front spring, allowing him to run the same pressure for any given height.
And as this means there’s a greater volume of air, it gives the vehicle a softer ride. When lightly loaded Todd runs the air springs at 45psi up front and 50psi at the back. He ups the rears to 60psi with a big load on board.
ARB’s new Hi-Output compressor provides the air without a back-up air reservoir. To improve the shockers, which always need to be A1 when air suspension is used, Todd upgraded to a set of Old Man Emu LTR’s on each corner. These are run at 80psi all round for all situations.
So how does it perform? As you’d expect from a system that costs in the vicinity of four grand or more, the Patrol rides bloody well. Across corrugations there is a smoothness not apparent with a normal coil-spring vehicle.
You can drive this Patrol across severe single bumps at a much greater pace, with a lot less harshness, thumping and crashing, than a standard Patrol. The amount of suspension travel is phenomenal. Basically it’s adjustable all the way from the bump stops – effectively below standard height – to four inches (100mm) above standard height.
In reality, the amount of suspension travel is only restricted by the amount of shock absorber travel. That means heaps in the rough stuff or with a load. After spending some time behind the wheel of Todd’s awesome air-spring Patrol, I now find myself trying to figure out how I can afford to fit this system to my stretched Patrol.
The Cost Factor
Front Air Spring Kit (OA4513): $1385
Rear Air Spring kit (OA4512): $1385
Accumulators: $150 each approx
In-car control kit: $680
*Prices do not include fitting
For more information on the system and your vehicle, whatever it may be, you can contact Todd on 08 9072 0917; WA Air Springs on 08 9350 6811; or check out airbagman.com.au.
Built not bought on Custom 4x4 reviews
Glamour & Punch
A list of aftermarket goodies on this Patrol makes it a stand-out.
- ARB bullbar and side rails
- Warn XD9000 winch
- IPF HID Super Rally driving lights
- HID headlight inserts
- Cooper ST tyres
- Safari snorkel
- United Fuel Injection (Perth) turbo upgrade with 12.5lb of boost and minor pump work
- Taipan three-inch mandrel bent exhaust system
- Coolfour (Repco) Intercooler custom modified to suit Patrol – at least twice the size of factory-fitted intercooler
- Extra small radiator to cool coolant straight from turbo
- Delphi adaptor for fuel cartridge
- Uni Filter air cleaner element
- MSA seat covers
- Black Widow drawer system, cargo barrier and drop-down table on rear door
- QMCC moulded ‘Sand Grabber’ floor mats
- Platinum drop-down fridge slide
- National Lunar Weekender 52L fridge
- ARB air compressor
- Uniden GPS 105 UHF radio with external GPS antenna
- Hema Navigator GPS
- Couplertec (4 anodes) rust protection system
- Red Arc Brake Trailer controller
- Red Arc dual battery system
- Rhino full-length roof-rack
- Bushranger Wheelie Bin tyre bag