JMACX · Land Cruiser 70 Series
A JMACX bolt-in coil conversion replaces the rear leaf springs on the Land Cruiser 70 Series with a purpose-engineered coil-spring rear end, improving ride comfort, axle control and stability across changing vehicle loads.
The quick explanation
A coil conversion replaces the factory rear leaf-spring suspension with a coil-sprung system that separates ride support from axle location. A fully welded structural cradle bolts into the chassis through a three-axis taper-lock system, while four trailing arms and a rear panhard rod form a heavy-duty 5-link arrangement that controls the differential under drive, braking and lateral loads.
The practical outcome
Coil springs support touring loads without the harsh response of an unladen leaf pack. The result is a calmer cabin, less rebound over washouts and more consistent comfort from daily driving to a fully loaded expedition build.
Four trailing arms manage acceleration, braking and axle rotation while the panhard rod resists lateral movement. This keeps the rear axle controlled under cornering forces, offset payloads and changing terrain.
The fabricated wide-track differential housing corrects the factory 100 mm front-to-rear track mismatch, helping the rear wheels follow the front wheel path and improving stability on loose or uneven surfaces.
The system supports 3900 kg or 4200 kg GVM configurations and increases the rear axle load rating to 2850 kg — important for canopies, bar work, towing equipment and permanent touring payloads. Final approval depends on the vehicle and South African requirements.
The conversion retains the vehicle's full 3.5-tonne braked towing capacity while creating a more controlled and stable rear-suspension platform for towing.
The upgraded housing retains factory Toyota brakes, hubs, bearings, seals and lockers. The suspension is designed around Toyota bushes, keeping common service parts familiar and easier to source when travelling.
For the technically curious
The conversion is more than a change from leaves to coils. These are the systems that locate the axle, carry the load and keep the chassis connection secure.
The axle is mechanically located instead of relying on the spring pack to control every direction of movement.
A heavily loaded LandCruiser creates substantial lateral force during cornering and when payload is offset to one side.
The vehicle chassis still needs to twist and flex naturally off-road, so the conversion must remain secure without chassis welding.
The structural cradle, fabricated housing and full-floating axle system work together as one load-carrying assembly.
Vehicle compatibility
Configuration is matched to the exact vehicle before installation.
The kit
Open any component below for its purpose, load path and installation role within the basic direct bolt-in conversion kit.
A patented structural cradle and heavy-duty chassis side plates bolt directly into the factory chassis. Three-axis taper-lock locators prevent movement across the mounting planes without welding the vehicle chassis or relying on a multi-piece frame that needs routine retightening.
The replacement heavy-duty housing widens the rear track to correct the factory 100 mm front-to-rear mismatch. Chromoly spindles support the increased axle load, while the housing carries the coil seats and mounting points required by the 5-link geometry. Factory brakes, hubs, bearings, seals and lockers are retained.
In a full-floating arrangement, vehicle weight is carried through the housing, spindles and hubs rather than through the axle shafts. The heavy-duty shafts, drive plates and caps are dedicated to transmitting drive torque in high-load applications.
The lower arms carry the primary acceleration and braking loads. The upper arms control axle rotation and provide adjustment for suspension geometry and pinion angle. The arms use Toyota-style bushes to support practical servicing and replacement-part availability.
The solid adjustable panhard rod resists side loads and keeps the differential centred beneath the chassis as the suspension moves. It is critical to predictable handling when cornering, carrying an uneven payload or operating with a high centre of gravity.
The heavy-duty adjustable sway bar and custom link kit connect both sides of the axle to tune roll resistance. Adjustment allows the installer to balance body control against articulation for the vehicle's finished weight and intended use.
Custom-fit tower mounts and rear coil seats place the springs correctly relative to the chassis and axle. Together with the cradle, they create the structural load path that allows the coil system to support the vehicle consistently through compression and articulation.
Flexible extended rear brake hoses, handbrake tabs, fuel-line brackets and brake-line brackets accommodate the replacement housing and increased suspension movement while keeping critical lines clear of moving parts.
High-tensile frame bolts, control-arm bolts and chassis locators are supplied for the conversion. Each group is matched to the structural cradle, links and factory mounting points used by the complete system.
Before installation
The basic kit provides the structural and mechanical framework. Coil springs and shock absorbers are specified separately to suit the vehicle's finished weight, load distribution and intended use.
The original exhaust must be modified or replaced to clear the 5-link geometry. A compatible 3.5-inch DPF-back system is one possible solution, subject to the exact vehicle specification.
Wheel and tyre load ratings must match the completed vehicle specification. Confirm South African certification, engineering and registration requirements with the approved installer before the build.
Coil conversions are information and enquiry only. Exact components, ride height, wheel and tyre requirements, GVM figures and engineering outcomes are confirmed for each vehicle. South African registration and engineering requirements are established during the enquiry and assessment process.
Next action
Send the exact vehicle, year, engine, current accessories, permanent front and rear loads and intended use.