What is an air jack?
An air jack is simply a bag, made from very strong plastic, which gets placed underneath the chassis of the vehicle when stuck or to change a wheel. It has a hose, which connects to the exhaust of the vehicle. The bags gets filled up when the engine starts and it will physically lift the entire side of vehicle. The bag has a control valve that allows for the controlled deflation of the vehicle to ground level. The large base of the air jack means that it will not easily sink into soft earth, mud and snow. It is also safer to use on rocky and uneven hard ground.

Recovery methods

“Jack and Push”
When bogged down due to high centre isle (middel-mannetjie), it is possible to lift the rear end of the vehicle and slew it sideways. This often positions the wheels in a better location for grip or in a better track. It is also possible to place sand ladders underneath the wheels for better grip. Hours of digging can be saved in situations like this.

Jack under the wheel
The air jack can also be placed underneath a wheel that lost traction or when a wheel is in a ditch thus allowing it to be lifted. It usually allows another wheel on the opposite side to gain enough traction to drive the vehicle off the air jack. With a towed recovery this will also allow for the chassis to be cleared off the ground. The vehicle can then be pulled little by little with the bag rolling under the vehicle.

Right a rolled vehicle
Air jacks can be used to roll a vehicle back unto its wheels in the event of a roll over and even returning it back to the road as it is relatively kind to the bodywork.

The belly flop Jack
A vehicle stuck on its chassis with front and rear wheels in the air can be recovered by jacking the rear until the chassis is cleared and then slowly drive off the jack.

Wheel Changing
It is best to place the jack that both wheels on a side lift. This method is much more stable. It is essential to chock the wheels to prevent forward or rearward movement of the vehicle. Take care with vehicles which hand brakes operate on the transmission and not the wheels themselves. Check the position of the bag before taking the full load of the vehicle. When the vehicle is at the required height, slowly remove the cone from the exhaust.

Jacking Positions
Many off road vehicles are fitted with protection plates. If possible lift under these plates. Take care that the plates can handle the pressure and is not simple stone guards that can easily give way. Jacking on cross members and chassis is also another good point. Be careful of jacking around tow hooks as sharp points can easily tear the bag. Most running boards are for show only and are not suitable for jacking the vehicle. If there is any concern about sharp edges then rather use vehicle mats to protect the bag. Stay clear from any sharp points and the hot exhaust pipe.

Advantages of using an air jack

• No special jacking points are required
• Can be used on soft roaders
• Can be used to push a vehicle upright.
• Can drive off an inflated jack without damaging the vehicle.
• Very quick to use.
• Weighs less than a hi-lift jack.
• Easy to use in and does not sink into soft surfaces.

Disadvantages of using an air jack

• Cannot be used to winch.
• Can be punctured.
• Relatively awkward size to pack (600mm diameter and 120mm deep)
• Expensive (R2200 for a Takla air jack vs. R600 for a Hi-Lift jack)
• Only fits round exhaust pipes – no fittings for oval or square tail pipes.

What to consider when purchasing an air jack

• Strong PVC material
• Protection on the bottom and top
• More than one method of inflation (exhaust and tyre valve)
• Quick release valve (on or off position)
• Pressure release valve in the event of over inflation.
• Repair kit included
• Lifting weight of 1500kg’s or more
• Inflated Height of +1m
• Deflated storage size
• Protection for the bag while in storage
• Get the best quality jack that money can buy.

Repairing Holes in the Air Jack
At the best of times a sharp object underneath the vehicle or on the ground can puncture the air jack. These small holes can easily be prepared.

• Clean the inflicted area, ensuring that it is free from grease or oil. If petrol was used to clean it then thoroughly clean with soapy water
• Lay the inflicted area flat.
• Use a patch from the repair kit and apply an even coat of the supplied cement glue.
• Press the patch over the hole.
• Apply an even pressure over the entire patch for a period of 1 to 2 minutes.
• Carefully remove the pressure and remove any dirt and grime.
• Wait a further 5-10 minutes before using the air jack again.
• A tear exceeding 3 cm might require a profession repair job.

Do’s and Don’t's

• The air jack is not designed for workshop use. Do not get underneath the vehicle while it is inflated with the air jack. This is what axle stands are made for.
• Do not quickly pull the cone off the tailpipe of a diesel engine while the bag is under pressure. The backpressure in the pipe will cause a cloud of black soot to cover you. Easing the cone off slowly will allow the pressure to be gradually diminished.
• The jack will not hold a vehicle up for long periods. It will slowly deflate by leaking through the seams or valve.
• Inflation is rapid and easy. If you are not happy with the position then reposition and re-inflate.
• Do not secure the cone to the exhaust pipe by means of cable ties.

Notes

• If the jack deflates immediately after removing the exhaust cone, it could be that the non-return valve was left in the open position.
• Inflation time depends on the vehicle. The Land Cruiser 1kz-te inflates the jack in 20 to 30 seconds. Larger engines will give a quicker gas flow and will inflate the jack quicker.
• The maximum inflation pressure is 0,7 bar.
• Be careful when lifting a vehicle on gravel, as it tends to create a rolling effect that can lead the vehicle to slide.
• Be especially careful on wet mud, as the air jack will tend to slide. It can even be held in place with your feet.

FAQ

What size Air Jack is required?
The Air Jack should be rated to lift at least 50-60% of the laden weight of the vehicle. Ensure that the maximum inflated height is enough to cater for the wheel articulation of the vehicle.

How is the Air Jack Inflated?
It is by means of the exhaust gas of your vehicle. It is required for the exhaust system to be in a good condition. The non-return valve prevents the air jack from deflation when pressure is removed from the exhaust system.

How is the Air Jack deflated?
Deflate the bag by switching the non-return valve to the open position.

What if it is twin exhausts?
If the exhaust runs form a single manifold then the one outlet must be blocked. If there are separate manifolds then inflation is per normal.

How stable and secure is the air jack?
It is recommended to use aids to ensure stability of the vehicle. Eg chock the wheels.

Can the air jack be over-inflated?
The air jack is fitted with a pressure release valve to prevent over inflation.

Is the air jack heat resistant?
Avoid making contact with the hot exhaust system, as it will melt the PVC.