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Back 4WD Accessories News Suspension Polyair Springs | Airbag Suspension
21 Jul 2012

Polyair Springs | Airbag Suspension


POLYAIR units are designed and engineered for long life. Provided you take a little amount of care when selecting and fitting your kit, maximum results will be obtained.


  • Stands or Jacks should be placed under differential housing so that dimensional relationship between vehicle chassis and Leaf Springs remains unaffected. A correctly attached chassis bracket has no stress on the attaching screws.
  • Kits are to be fitted not more than 40 mm and not less than 20 mm in front of or behind the differential housing, usually fitting instructions specify the correct location, depending on positions of brake lines, exhaust pipes, petrol tanks, shock absorbers and other obstructions. Should any of these have been altered from original specifications then repositioning of the kit may be necessary.
  • Clearance from any obstructions should be a minimum of 20 mm (Exhaust Pipes 60 mm at all times).


  • Most bags can be fitted between the lowest coil opening when suspension is fully extended. Additional clearance between the coil may be obtained by removing lower shock absorber mountings and lowering suspension 30-50mm.
  • Bag should be a reasonably snug fit in the coil, however tolerance of +/- 6mm is common.
  • CAUTION: Observe tension on brake hose. DO NOT STRAIN.
  • (If the vehicle has a hole between bag and spring seat / chassis of 50 mm / 2" or more than half the diameter of the bag (whichever is the smaller) then a protector must be fitted. This is normally included in the kit.
  • Ensure that exhaust tail pipe is 60 mm from Polyair Bag. If necessary, loosen clamps and rotate or move to obtain additional clearance.


All vehicle springs will sag, and the amount of sag depends on age and usage conditions (eg load variety, towing etc). As the kit is designed to fit the vehicle's as new specifications, an older vehicle will probably require a few more KPAs when unladen to restore it to original ride heights and this factor will vary by how much the front may have sagged.

All kits are supplied with fitting instructions and air extension hoses.

Should it be necessary, POLYAIR SPRINGS can supply kits specially tailored to suit an off-standard situation such as Raised or Lowered Suspension Systems or BADLY SAGGED suspensions.

If your vehicle is not listed or does not conform to the specification list, let us have the inside diameter of your coil, the length required for your air bag (measured when the vehicle is empty standing on level ground). Please mention in addition if any obstruction and/or holes are at the top or bottom of your existing coil springs.

LOW PRESSURE GAUGE: To prevent damage to the air bags, a minimum pressure of 35 KPA / 5 PSI should be retained in the bags of standard kits at all times. A special low pressure dual dial gauge with readings from "2" to "60" lbs (10-400 KPA) accurate to within 2% of scale for this critical low pressure air adjustment in POLYAIR SPRINGS is available. The gauge will double up as a tyre gauge.

CAUTION: Leave sufficient hose slack to prevent any strain on valve stem during axle motions. To prevent extension from melting, keep it at least 60 mm from exhaust system.

GENERAL MAINTENANCE TIPS: After fitting kits and/or extension leads, inflate air bags to 175 KPA / 25 lbs and test for air leaks by applying a liquid soapy solution to all valve cores, fittings and connections.

Caution - Do not inflate air springs while vehicle is on frame hoist. Vehicle must be standing on its wheels before bags are inflated.

  • Maintain at least 35 KPA / 5 PSI of air pressure in the Air Lift Bags to prevent chaffing.
  • Inflate your Air Bags before loading your vehicle to maximum pressure indicated on fitting instructions.
  • Do not attempt to raise a loaded vehicle by inflating Air Bags. If loaded, jack up body until level, then inflate.
  • It is recommended that tyre pressure be increased by 14 KPA (2 lbs) above normal for each 45 kg / 100 lbs total overload on the axle.
  • POLYAIR SPRINGS recommends that the kits be used to support loads which are within the vehicle manufacturer's rated GVW.

Recommended standard Air Lift Bag pressures are included in installation instructions and vary from kit to kit. Typical values are min 35 KPA / 5 lbs, max 175 KPA / 25 lbs.

Call 4WD World on 1800 807 176



Visit 4WDWorld.com.au for a quote on your 4WD Accessories or freecall 4WD World on 1800 807 176


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