Boss Air Suspension
Boss Air Suspension Load Assist Kits
If you tow, load up the tray, or carry camping gear for the next trip, a sagging rear end is more than an annoyance. It throws off your headlights, pulls your steering light, and makes the vehicle harder to control on a wet road or in a crosswind. Boss Air Suspension load assist kits fix that. 4x4 Down Under stocks genuine Boss kits built to level out your ute or 4WD when it's under load, so you get safer towing, flatter cornering, and a vehicle that sits the way it should whether you're empty or fully loaded.
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Boss Air Suspension is a Queensland-based company operating out of the Gold Coast. Since setting up its own airbag manufacturing in 2005, Boss has sold more than 45,000 load assist kits to Australian customers and stands behind every airbag with a 5-year warranty, on-road and off. That track record is why 4x4 Down Under carries the brand as one of our go-to options for load assist across popular utes and 4WDs.
How a load assist kit works
A Boss load assist kit pairs an airbag with your vehicle's existing rear leaf springs or coils. Empty, the bag sits mostly deflated and the standard suspension does the work. Load the tray, hook up the van, or throw the camping gear in the back, and a few pumps of air firms the bag up to bring the rear end back to level. That keeps your headlights aimed correctly, keeps weight on the front wheels for steering and braking, and cuts down the sway that a loaded rear end causes in crosswinds or when a truck passes, a factor the NSW Government's guide to towing a trailer or caravan flags as a common contributor to loss of control. Drop the air back out and the kit gets out of the way again for the unloaded drive home.
Kits are designed to bolt onto the factory mounting points using basic hand tools, so most owners can fit one in the shed over a weekend. No cutting, drilling, or welding. Each kit is vehicle-specific, supplied with brackets, air line, and fittings to suit the exact make and model, and can be upgraded later with an onboard compressor and control kit if you want to adjust pressure from the driver's seat.
Why Boss airbags hold up
Boss builds its own airbags rather than relabelling someone else's, and the construction shows it. Each bag uses cured natural rubber reinforced with ballistic woven fabric and steel support wires, nine running through the centre plus four at each end, capped with 6mm zinc-plated steel end plates. Boss rates the bags to a recommended working range of 5 to 160 psi, with an independent test pressure of 480 psi and a burst pressure over 600 psi. One bag in every hundred off the line is pressure tested to destruction in a controlled chamber as an ongoing quality check.
That build quality matters because a failed airbag under load isn't just inconvenient, it can leave a laden vehicle sitting on the bump stops. Boss backs its bags with a 5-year warranty for exactly that reason.
Specifications
| Bag construction | Cured natural rubber, ballistic woven reinforcing, 6mm zinc-plated steel end caps |
| Support wires | 9 high-tensile central wires plus 4 at each end |
| Recommended working range | 5–160 psi |
| Independent test pressure | 480 psi |
| Burst pressure | Over 600 psi |
| Warranty | 5 years, on-road and off-road |
| Fitment | Vehicle-specific bolt-on kits, no cutting, drilling, or welding |
What's covered in this range
4x4 Down Under stocks Boss Air Suspension load assist kits for a wide range of popular utes, 4WDs, and vans, including Toyota Hilux, LandCruiser, and Prado, Ford Ranger, Mazda BT-50, Isuzu D-MAX, Mitsubishi Triton, Holden Colorado, RAM 1500 and 2500, and Chevrolet Silverado, along with universal kits for less common applications. Use the vehicle filters on this page to find the kit built for your exact model, or get in touch with our team if you're not sure which one fits.
Boss Air Suspension vs cheap import kits
Budget import load assist kits are easy to find, but a lot of them use thinner rubber, fewer support wires, and steel-crimp joins that are prone to slow leaks over time. Boss builds and tests its own bags in-house, backs them with a proper warranty, and has a track record of over 45,000 kits sold to Australian owners towing caravans, running camper trailers, and hauling tools and gear for work. For a part that's holding your rear end level at highway speed, that difference is worth paying for.
Frequently Asked Questions
What does a load assist kit actually do?
It adds an air-adjustable support to your existing rear suspension. Pump it up when the vehicle is loaded to bring the rear back to level, and let air out when you're driving empty.
Will I need a compressor to run a Boss load assist kit?
Not necessarily. Kits come with a basic inflation valve you can top up with a portable 12V compressor, foot pump, or service station air hose. Boss also sells onboard compressor and control kits if you want to adjust pressure from inside the cabin without getting out.
Can I fit a Boss load assist kit myself?
Most owners can. Kits bolt onto the factory mounting points with basic hand tools, no cutting, drilling, or welding required. Each kit comes with the brackets, air line, fittings, and instructions for your specific vehicle.
Do Boss load assist kits replace my leaf springs or coils?
No. A load assist kit works alongside your existing rear springs rather than replacing them. If you need a full ride-height lift or a heavier-duty spring rate, that's a different product, so speak to our team about your setup before you buy.
How long do Boss airbags last?
Boss backs every airbag with a 5-year warranty for on-road and off-road use. The bags themselves are built with reinforced rubber, steel support wires, and zinc-plated end caps, and Boss pressure-tests one bag in every hundred to destruction as a quality check.
Does 4x4 Down Under stock a kit for my vehicle?
Boss makes vehicle-specific kits for most popular utes, 4WDs, and vans on the Australian market, plus universal kits for less common applications. Filter this collection by your vehicle make and model, or contact our team if you can't find your exact fitment.
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