LAND ROVER DEFENDER AIR SUSPENSION REPAIR & UPGRADE


JOB:  REPLACE AIR SUSPENSION BAG AND ADD A CONTROLLER UPGRADE.

WHY THIS JOB MATTERS AND WHAT WAS DONE.

This Defender had already been outfitted with a full air suspension system by On Air Suspension Ltd, giving adjustable ride height and custom comfort modes. When a small nick appeared on one of the air bags, the owners contacted us for a replacement. On Air, supplied us with the repair kit and our job was to fit a replacement air bag and install a new controller unit that provides multiple ride modes (on-road, off-road, raised front / rear, left / right, and access height).


This repair is more than just cosmetic, however, a faulty bag can lead to ride height imbalance, poor handling, or even leave the vehicle unusable if the system cannot maintain pressure. By carrying out this work, we preserved the integrity of the system and ensured the Defender could continue to operate with full benefits of air suspension.

ABOUT THE ONAIR SUSPENSION SYSTEM.

On Air offers retrofit air suspension kits for Defenders, Range Rovers, Grenadiers as well as emergency vehicles and transit vans. Their Defender 4-Corner Full Air kit includes air springs, compressor, ECU, and a control system with advantages including a:

  • Maintained ride height under varying loads.
  • Fully adjustable height settings and modes.
  • Enhanced vehicle stability and improved ride comfort.
  • Optimised suspension geometry and control logic.


Because they design their strut mounts, shock mounts, and brackets in-house, their kits aim to minimise structural compromises and maintain robust geometry.

SYMPTOMS & CONSEQUENCES OF AIR SUSPENSION FAULTS.

Owners should be aware of warning signs before a small issue becomes a big problem:


  • Drooping / sagging side. This is when one corner sits lower than others.
  • Inconsistent ride height. Where the vehicle fails to level after activation.
  • Audible hissing / leak sound which indicates a slow leak in bag, fitting, or airline.
  • Compressor runs excessively to try maintain pressure, which can lead to overheating or failure.
  • Controller faults or error lights signal an electronic failure in the ECU or sensor.
  • Vehicle tilt or handling issues. If one side fails substantially, the geometry is off.


If left unchecked, these faults can stress other suspension components, degrade ride comfort, or in worst cases leave the vehicle stuck in a low mode.

01

ADJUSTABLE RIDE HEIGHT & MODES: YOU CAN LOWER OR RAISE THE VEHICLE FOR ACCESS, OFF-ROAD OR VISUAL EFFECT.


02

IMPROVED COMFORT: AIR SPRINGS CAN ABSORB ROAD IMPERFECTIONS SOFTER THAN COIL SPRINGS.


03

LOAD LEVELLING/ CONSISTENT GEOMETRY: WHEN THE VEHICLE CARRIES VARYING LOADS, AIR SUSPENSIONS CAN MAINTAIN THE CORRECT RIDE HEIGHT AND ALIGNMENT.


04

BETTER HANDLING UNDER VARIABLE LOADS.


THE PROS OF AIR SUSPENSIONS.

THE CONS OF AIR SUSPENSIONS


LIKE EVERYTHING IN LIFE THERE ARE POTENTIAL RISKS. HOWEVER THE AIR SUSPENSION KIT, OVERALL, IS A GOOD INVESTMENT AS ANY TYPE OF SUSPENSION CAN DEGRADE OR FAIL. AT KEITH GOTTS, WE CAN TRACE ANY POTENTIAL FAULTS AND FIT IN NEW AIR SUSPENSIONS IF NEEDED.

01

THE INITIAL COST OF THE KIT AND INSTALLATION CAN BE EXPENSIVE.

02

THERE ARE MORE COMPONENTS AND MAINTENANCE POINTS WHICH CAN INTRODUCE MORE FAILURE POINTS.


03

BAGS, SEALS AND FITTINGS MAY DEGRADE OVER TIME, CAUSING LEAKS.


04

THE DIAGNOSTICS OF AN AIR SYSTEM CAN BE SLIGHTLY HARDER TO TRACE THAN A COIL SETUP.


THE REPAIR PROCESS AND WHAT WE DID.

This is how we handled the repair and upgrade, step by step:

  1. Diagnostic & isolation – We were made aware of the damaged air bag and confirmed the fault in the section.
  2. De-pressurisation & removal – we carefully deflated the system and removed the defective bag, maintaining alignment of brackets and fittings.
  3. Fitting the replacement bag – we installed the new air spring, ensuring correct orientation, seal integrity, and eliminating any sharp edges in the mount area.
  4. Controller swap / install – installed a new control module and associated wiring / sensors. This enables the new ride modes (raised front/rear, left/right, off-road, access height, etc.)
  5. Bleeding & calibration – we bled the air lines, calibrated height sensors, and ensured symmetrical response on all corners.
  6. Testing & final adjustment – with the system live, we tested the modes, ride heights under load, and road-tested to check for leaks or uneven settling.


Because of our Land Rover & Defender experience, we took extra care in aligning turnbuckle lengths, securing airlines, and protecting vulnerable lines from abrasion or road debris.

ARE AIR SUSPENSIONS THE FUTURE?

It’s worth pondering this: many high-end SUVs and modern vehicles already include factory air suspension for comfort, load management and height control. As technology improves, we may see more rugged and durable air setups becoming viable for serious 4x4s.


  • In a 4x4 context, a well-designed air system can allow on-the-fly adjustment for rocky trails, deep water, highway cruising height, or loading.
  • Durability, component cost, and repair logistics can be barriers in remote or harsh environments, but OnAir's kit is proof of advancement.
  • For many utilitarian owners, the simplicity and reliability of coil/leaf setups remain preferable.
  • Hybrid systems or semi-active systems may form a middle ground in future designs.


It is not farfetched to say that for premium off-roaders, air (or electronically adaptive) suspension may become a standard option, but only if component reliability, serviceability, and cost is favourable.




WHY SHOULD YOU TRUST KEITH GOTTS FOR YOUR AIR SUSPENSION WORK?

  • We have deep Land Rover and Defender experience, so we understand the structural, geometric and component constraints.
  • We maintain high standards in installation, alignment, sealing and diagnostics.
  • We test each installation with real road testing under load to ensure the system performs as expected.


If your Defender or Land Rover is running an air suspension system and you notice sagging, slow response, leak noises or inconsistent ride height — don’t ignore it. Early diagnosis and repair can prevent bigger failures.

Contact our service team to book an inspection or repair, and let us bring your air suspension back to peak performance.