Suspension Kits

Specialised Fittings for improved Off-Road Performance

4WD Systems manufactures and supplies a wide range of Specialised Fittings for the Hardcore Off-road enthusiast. Designed to counter the issues of over height lifts – Steering, Wheel Alignment, Articulation, Track Width or other requirements for Extra Strength Parts – this range of fabricated parts has been designed for ultimate functionality.

Extra Lift
Body Lift Blocks
Body Lift Kits
Coil Spacers
Extended Greasable Shackles
Front Strut Spacers
Rear Lift blocks in 1 and 2″ with extra long Ubolts
Coils Spacers

Wheel Alignment & Geometry
Castor Wedges
Castor Plates
Castor Bushes
Drop Boxes
Drop Arms
Extended Ball joints
Camber Adjustment Bolt Kits
Adjustable HD Drag Links
Adjustable HD Tie Rods
Diff Drop Kits
Bash Plate Spacers

Articulation & Handling
Extended Sway Bar Links
Extended Brake Hoses – Standard Rubber
Extended Brake Hoses – Braided Stainless Steel

Track Width
Wheel Spacers from 1/4″ to 2.5″

When contemplating suspension replacement, the following are the questions that should be considered:

Vehicle Set-up:
Is it Petrol or Diesel?
Is it fitted with a Bull Bar – Steel or Alloy or Plastic?
Is it fitted with a Winch &/or Dual Batteries &/or after-market Turbo or Intercooler?
Is it fitted with a Canopy?
Is it fitted with Long Range Fuel or Water Tanks or LPG cylinders?
Do you have Draws or anything else heavy in the vehicle?
Do you perform any significant Towing?

Vehicle Use:
Is it a Daily driver to and from work with minimal or no Load?
Is it used as a ”Tradie” vehicle with a Constant Load or Towing a Load?
Is it fitted a SWC or Twin SWC?
Is it used for Short recreational trips?
Is it used for Extensive Outback trips ?

Vehicle Condition:
How many kms has the vehicle travelled?
What amount of lift are you looking for?

Notes to assist with ordering Suspension:

• Generally a diesel engine will weigh more than a petrol engine – Constant Load
• Steel bull bars weigh more then Alloy or Plastic – Constant Load
• Electric winches are normally accompanied with Dual Batteries & Steel Bull Bars – Constant Load
• Canopies are a constant weight on the rear springs, as are front fitted accessories.
• For daily use ride comfort is important – this would lead to Medium Duty.
• For a Tradie vehicle it shouldn”t be harsh riding, but it is expected to carry a load or tow most days, so load carrying is important on the rear – Constant Load
• For shorter trips loads are probably lighter, so Medium load springs are preferred to give the best ride.
• For bigger trips load carrying is important, so either constant load or occasional heavy load springs are suitable. In this case HD or XHD springs will be required, or
• medium springs in concert with an Airbag Kit.
• Airbags not only support the load, they reduce shock fade in very arduous terrain.
• Remember, HD springs with load will flex & ride like medium springs do with a lesser load.
• The Total Weight load needs to be considered and calculated with use in mind.
• It is well established that OE suspension parts have poor qualities to begin with, so expect to replace them from 50 to 100,000kms if not much sooner if loaded.
• Take into account the tyre size, and fit a lift that keeps the vehicle ”in balance”. Small tyres with a high lift looks odd, as do oversized tyres with a small lift.

Coil Springs

Sold as a Pair

OE coils are well known to have a limited life and perform poorly during that life. Often sag in the rear with less than legal load capacity.
4WD Systems coils are precision manufactured, heat treated in an electronically controlled furnace, Shot Peened, Scragg & Load tested – all processes aimed at eliminating long term sag and maintain performance.

Available in a variety of coil wire diameters and numbers of coils, providing a range of options of ride height, ride comfort and load carrying capacity for different applications on the same vehicle.

Linear Rate (evenly spaced coils) – Improved ride and load carrying
Progressive Rate (variable spaced coils) – excellent ride with acceptable loaded height

”Progressive Rate” coils can be made to sound like nirvana by the inexperienced Salesperson but unfortunately this is often NOT the case. When loaded, the Progressive Rate Coil will often ”sit-down”, the close wound coils will go ”coil-to-coil”, (metal to metal), so that part of the coil has no movement at all. Immediate loss of height.

Be honest and accurately calculate the extra weight of accessories fitted and load when considering what coil your vehicle needs. Don”t forget, HD springs with load will flex & ride like medium springs do with a lesser load.

Available:
Ride Comfort – Medium Load (Linear or Progressive)
Heavy Duty – Constant Load or Occasional Heavy Loads (Linear Only)
XHD – for Excessive loads (Linear Only)

Consider Air Bags for HD or Excessive Loads, particularly if there is a big variation in load.

Leaf Springs

Sold as Each

Original leafs are well known to have a limited life and perform poorly with a harsh ride during that life. Often sag in the rear with less than legal load capacity.

4WD Systems leafs are manufactured from SUP9 high grade spring steel, have drawn & tapered leaf ends to reduce friction – greater heat dispersal to reduce wear, have ”military wrap” for extra support of the spring eyes, precision manufactured, heat treated in an electronically controlled furnace, Shot Peened, Scragg & Load tested – all processes aimed to eliminate long term sag and maintain performance.

4WD systems Leafs have increased height for ground clearance and increased bump stop distance – hence more time to absorb a bump, improved ride over standard leafs.

Accurately calculate the extra weight of accessories fitted and load when considering what leafs your vehicle needs.

Available:
Ride Comfort – Medium Load
Heavy Duty – Constant Load or Occasional Heavy Loads
XHD – for Excessive loads
Consider Air Bags in conjunction with HD leafs for Excessive Loads

Remember, HD springs with load will flex & ride like medium springs do with a lesser load, and grease able shackles and pins will add extra flexibility – help to compensate a tight ride with inherent in HD leafs with minimal load when empty.

Air-Bag Load Assist Suspension

Sold as Kits with all components – air lines, valves, ties & fasteners.

Coil Bags – Fit inside the coils.
Bellows Bags – Mount between the chassis & differential housing on Leaf sprung vehicles.

Both used to support load by varying air pressure.
Both can be used for Extra Stability (rather than actual load carrying) for high loads.

Each application is specifically designed to maximise the safe load carrying capacity and stability of the vehicle, without increasing the manufacturers Gross Vehicle Mass (GVM).

Maintains front to rear level, hence improves braking effectiveness, and improved steering control with heavy loads or heavy towing. eg Slide-on Campers, Water Tanks/Fire units, Horse floats, Boats and Caravans.

Increases side stability.

Adjustable to suit varied load mass, even varying inflation in each bag to achieve side to side adjustment.

We can supply XHD springs but if your vehicle does big outback trips with heaps of weight and suspension articulation (eg Canning Stock Route, Simpson Desert Crossing, Cape York etc), then airbags will provide not only ”load assist” but also limit shock-absorber overheat and shock-absorber tower failure.

It is not recommended that airbags ONLY are used, except for moderate use on reasonable roads. The single point loading that comes from not sharing the load into the chassis via the spring mounts (hence 3 load points for leaf spring vehicles) can result in chassis damage in excessively loaded vehicles driven for extended periods over harsh terrain.

If used in conjunction with HD springs, the load is shared into the 3 points of the chassis, hence substantially reducing any risk of chassis problems.

If existing air bags are fitted, then spacer blocks can be added to make these bags useful with higher springs.

Available for a wide range of models.

Torsion Bars

Sold as a Pair

Have an increased spring rate or load capacity by increasing the diameter relative to standard (and higher quality material).

This has several advantages:

• reduces brake dive under severe or sudden braking that results in loss of traction
• reduces body roll during cornering
• reduces tyre wear by maintaining correct wheel alignment longer

The IFS Torsion Bar front is a flexible design that provides good ride comfort due to the control arms moving independently of each other (with limited wheel travel it has to be said (fit a Lokka to overcome the traction loss) but the limited wheel travel cannot be changed without significant expense).

However the Torsion Bar design uses quite ”short bodied” shocks, hence low oil capacity (compared to long bodied shocks used in other suspension designs).

For these applications the larger the oil capacity (hence piston diameter), the better. The limitation is clearance from other components in the confined space.

With Torsion Bars, our usual ”rule of thumb” is:
If its done a reasonable number of kms or had a hard life – upgrade them.
If its got a significant front bar or winch – upgrade them.
If there is a significant lean to one side or a wide variation in the adjusters – upgrade them.
If not, then simply adjust the existing Torsion Bars. Ride will be better with original bars and minor front load.

In the case of the Nissan Navara D22, the early versions (pre-2002) had 24mm diameter Torsion Bars and the after-market size was a healthy 26.5mm – a good increase.
The later D22 have 26mm bars standard, so the increase to 26.5 is hardly worth it. Better to spend on more worthwhile components (read larger diameter shock-absorbers) – in virtually every case.

For IFS Torsion Bar suspensions, the upper bump stop on most applications should have approximately 10mm clearance to give adequate ”down stroke”, yet achieve good height increases over standard.

Upper Ball Joint Spacers are available for some models – to allow for greater travel and adjustment. Fit with Diff Drop Kit.

Shock Absorbers and Struts

Sold as Each

General background
Many ”factory” shocks have 30mm diameter pistons with relatively poor sealing around the piston head and a restricted length of travel. The volume of oil is limited, increases in temperature rapidly, losing viscosity, hence less damping effect. The poor seal allows ”bypass” – hot hydraulic oil under pressure leaks past the piston head that contains the valve stack. The shock soon looses control of the spring – known as ”fade”.

Larger internal piston diameter and longer travel results in a substantial increase in the total hydraulic fluid oil capacity. Increased oil capacity results in greater heat dissipation, leading to higher retained viscosity which means greater effective damping action for longer – there is cooler, thicker oil porting through the valve stack in the piston head.

Additionally, multiple stage velocity sensitive valving improves response to varying road and track conditions. The valve stack is velocity sensitive, sensitive to the velocity of shock absorber movement. Two obvious different events are – a pot hole at 100 km/hr vs a slow undulation on road at 60 km/hr – is accommodated by different valving in the piston head. The greater the number of valves the smoother the transition from speed to speed, hence smoother more controlled ride.

4WD Systems has 2 shock absorbers in the range:
35mm Nitro-Gas shock
41mm Foam-Cell shock (often known as Cellular Gas)

Both have a 14 valve in the stack, with an effective multi-lipped Teflon seal around the piston head to minimise piston head by-pass.

The increased diameter and stroke of the 35mm shock over the original does provide a noticeable improvement. However the 35mm gas shock does not have the capacity to work as hard as the 41mm shock, so its application tends towards lighter vehicles and leaf sprung vehicles where the friction between the leafs assists in the damping of the spring.

The size (35 or 41mm) represents the piston diameter, so the greater that number the greater the oil capacity, hence oil temperatures are lower. Cooler oil results in greater viscosity, and importantly – less Fade.

We usually suggest you consider the 41mm Foam Cell shock. While the 35mm Nitro Gas will do for a while, they wont last like the 41mm”s.

All shocks have oil in them, this is what does all the work, as the oil moves through the valving in the piston head it is restricted by the valving.
Shocks work at their hardest on corrugated dirt roads at moderate speeds or faster. The repetitive rapid movement of the piston results in heat build up, hence oil viscosity drops and the shock fades. Slowly articulating over big rocks etc requires great articulation and balance – but doesn”t make a shock fade.

The ”Foam Cell” takes up the space of the gas (in Nitro-Gas shocks) or air in standard OE shocks. The ”Foam Cell” is comprised of a multitude of minute sealed gas chambers (called cells, hence Cellular-Gas) that prevent the oil and gas mixing, unlike the gas in Nitro-Gas shocks or Air in OE shocks – which can become aerated from this mixing.

Aeration also occurs due to the hydraulic oil boiling or bubbling as the shock extends rapidly after compression. The ”vacuum” or pressure reduction created as the piston head moves quickly away from the hydraulic oil allows the oil to boil at a lower temperature than when under ”normal” pressure.

The compressed gas chambers in the Foam Cell expand as fast as the piston head moves (after compression), forcing the oil back through the valve stack, hence maintaining a more normal pressure on the oil. The likely-hood of ”low” pressure – low temperature boiling is reduced.

Original shocks and 35mm Nitro Gas shocks both aerate in extended severe conditions due to oil-gas mixing and low pressure boiling of the hydraulic oil.

That said, it depends on the vehicle set-up and more importantly the use of the vehicle to determine which shock is best.

For example, If your ”thing” is beach fishing, then smaller capacity shocks are fine, as driving on soft sand doesn”t develop heat, therefore viscosity loss, leading to shock fade. Driving for hours-on-end over outback corrugations with 2 weeks worth of supplies on board is really tough on shock-absorbers.

Also of note:

• Vehicles with Leaf springs require less damping. The friction between the leafs assists the damping process and there is less reliance on the shock. This is particularly true for lighter vehicles.
• Heavy loaded leafs will last longer with the protection afforded by larger capacity shock-absorbers.
• Independent Suspension (IFS & IRS) vehicles have particularly short bodied shocks with minimal oil capacity so they improve significantly when larger capacity shocks are fitted.

Steering Dampers

Sold as Each

Standard Replacement have 30mm piston diameter. Used on vehicles with standard size tyres OR minimal Off-Roading.

HD Replacement have a 35mm piston diameter. Used on vehicles with larger tyres OR more Off-Road use

Coil-Over style have a 35mm piston diameter piston with external coil spring mounted on the damper body. Used on vehicles with over sized tyres OR very high lift OR to neutralise ”front-end shimmies”.

XHD Coil-Over style have the 35mm diameter piston with XHD coil mounted to the damper body. Used on more extreme examples of above, 35″ or larger tyres.

Castor Correction

Castor Correction – by Bushes, Plates, Drop Boxes or replacement Drop Arms – for lifts over 50mm (2″).

For lifts below 50mm (2″) it is advisable but not mandatory. Generally 4WD vehicles will have less Castor Angle than the equivalent year 2WD, and most 4WD”s will benefit with extra Castor above standard.

There are various arguments for and against the differing ways of achieving improved Castor Angles. Briefly:

1. If the radius arm bushes are already tired (commonly the case), then replacing them with 2.5 to 3degree Off-set Bushes, makes perfect sense (assuming you have to do the bushes anyway), but you require access to a press – to remove and fit the new bushes, and if you need a greater increase of Castor Angle than 3degrees, (for lifts above 3″), then you may have to replace both the Bushes and fit Castor Plates.
   Sold as a Kit
2. The Castor Plates are easier for a DIY at home, as you dont have to remove the arms and press the bushes out or in. And the result is approx 5 degrees more Castor (compared to 3degrees with the bushes)
   Sold as a Kit
3. (For Patrol ONLY) – Drop Boxes achieve the goal of greater castor but also have the advantage of putting the radius arms back to a more ”normal” geometry – ie horizontaly pushing forward, rather than ”angling down”. This improves stability. When the arms are at a steep angle it can feel a bit like you are driving on ”stilts”.
   Also the rear T bushes on the arms allow articulation by compression of the bush, if it is already under compression due to the ”steep” angle, there will be reduced movement of the arms – particularly hanging down.
   Sold as a Kit
4. Others do not like the Drop Boxes – because they hang down a bit and if you are sliding over rock ledges etc then this is a definite ”hook-up” point. They prefer the new longer Radius Arms which result in an equivalent amount of Castor with good geometry.
   Sold as a Pair (bushes extra)

So it depends on your budget and your use of the vehicle as to the best option to achieve greater Castor Angle.

Poly Urethane & Rubber Bushes

Sold as a Kit

Are designed for factory or 4WD Systems leafs (unless otherwise stated). They are not a replica of the original rubber bush, they have ”pockets & slots” to trap grease – to improve ride and life of the springs and the bush themselves.

Other Suspension Bushes are available for most Control Arms & Panhard Rods.
Kits sold ”per rod” or as a Complete Vehicle Kit

Greaseable Fixed End Pins & Swinging Shackles

Sold as Each

Are designed for factory or 4WD Systems leafs (unless otherwise stated).

Used to facilitate satisfactory lubrication of bushes and leafs – to extend life and improve ride.

The grease applied during initial fitting will wear away/dry (in time) or be washed away by water and mud – so it makes sense to be able to apply grease right into the centre of the bushes and spring eye.

U-Bolts

Sold as Each

Manufactured from high tensile 10.9 grade steel. To suit Ride Comfort & Constant Load leaf packs.

Ancillary Parts – Generally for 3″ or larger Lifts

Note 1.
For Nissan Patrol lifts over 3″, the steering box will move ”off-centre” as the factory Drag Link (which goes from Steering Box on RH chassis to the LH front wheel) is non-adjustable. So it is advisable (but not mandatory) to fit an HD Adjustable Drag link, to get the steering box back to centre. (especially the case when SRS airbags are fitted and removing the steering wheel is problematic).

Extended Brake Hoses

Braided Stainless lines eliminate the ”spongy” feel observed in extreme braking conditions – sometimes observed with rubber lines. Stainless exterior also provides resistance to corrosion and abrasion.

Swagged directly onto hand drawn tensile stainless steel braided Teflon hose. However, good quality new extended Rubber Lines are satisfactory for most high lift applications.

Specialised Fittings for improved Off-Road Performance

4WD Systems manufactures and supplies a wide range of Specialised Fittings for the Hardcore Off-road enthusiast. Designed to counter the issues of over height lifts – Steering, Wheel Alignment, Articulation, Track Width or other requirements for Extra Strength Parts – this range of fabricated parts has been designed for ultimate functionality.

Extra Lift
Body Lift Blocks
Body Lift Kits
Coil Spacers
Extended Greasable Shackles
Front Strut Spacers
Lift blocks in 1 and 2&Prime with extra long U-bolts for Leaf springs
Coils Spacers

Wheel Alignment & Geometry
Castor Wedges
Castor Plates
Castor Bushes
Drop Boxes
Drop Arms
Extended Ball joints
Camber Adjustment Bolt Kits
Adjustable HD Drag Links
Adjustable HD Tie Rods
Diff Drop Kits
Bash Plate Spacers

Articulation & Handling
Extended Sway Bar Links
Extended Brake Hoses – Standard Rubber
Extended Brake Hoses – Braided Stainless Steel

Track Width
Wheel Spacers from 1/4″ to 2.5″

Some products may not comply with State Regulations
Check local authority before fitting or street use on road

Fitting

A Fitting Guide is provided for DIY.

An additional Record Sheet is provided to record the ”Before” and ”After” height measurements.

We recommend a wheel alignment is performed in conjunction with fitting suspension components.

The rear Brake Proportioning Valve should also be adjusted (if fitted) so braking performance is maintained at the new height.

Warranties

Kits using 41mm Foam Cell dampers have a 3 Year Unlimited km Warranty.

Those with 35mm Nitro Gas dampers have a 2 Year Unlimited km Warranty – even though the other components are identical. This is because the larger shocks provide a higher level of protection to the other components.