Test all limits in the Nissan Navara
Test all limits in the Nissan Navara

Smooth operator

Soon after purchasing a 2004 Land Cruiser 100 Series that will form the basis of our Budget Overland Build (BOB), we realised the old girl needed a bit of TLC. We took her to Halfway Toyota in Honeydew, who gave her a full service, fixed damage to some electrical wiring caused by rats, and replaced parts of the steering rack. The next phase of our build was a very necessary suspension upgrade, which brought us to Ironman 4×4 South Africa’s premises in Alberton.

A standard 4×4 vehicle can take on the rigours of mild overlanding, but its suspension limitations become clear as loads increase. If you want to fit body armour to protect the vehicle (think bullbar, rear-wheel carrier bumper, underbody protection) you use up load capacity. Add passengers and camping equipment, and soon your ride is settled far too low and hitting the bump stops on every dip.

Fitting an aftermarket suspension is the solution here. Heavier-duty springs will take care of the added loads, beefier shock absorbers will keep the damping and ride characteristics under better control, and the extra ride height will enable you to clear bigger obstacles – and perhaps fit larger tyres. Those are the principal advantages, with the massive benefit being a greater margin of safety when you travel.

When it comes to repurposing an older vehicle for overlanding, a knackered suspension will make it dangerous to drive unloaded a low speed, let alone when crammed with people and equipment. Which brings us to our own 17-year-old Land Cruiser 100 Series. It’s a luxury VX model, with a petrol V8, independent front suspension (IFS) and 270 000 fairly hard kilometres under the chassis, all of which has taken a toll on the components.

IFS & AHC – the problem

The 100 Series IFS versions are distinct from the 105 models which use a solid axle front and rear, carried on coil springs. These are considered the hardier models, with more axle articulation up front and a stiffer ride. The IFS models offer less suspension travel as they use control arms sprung on a torsion bar up front with a solid axle on coils at the rear only. On the plus side they offer more direct steering and all-told a more comfortable ride.

This is largely because the IFS models use Toyota’s then advanced Active Height control (AHC), a rather complex arrangement of sensors, four accumulators, a hydraulic pump and fluid-filled adjusting shock absorbers. This enables drivers to select a low ride height for when unloading/loading, a neutral setting for the road, and a special high setting for off-road conditions. The system is speed dependent, working in the background at low speeds to draw fluid from the shocks to a reservoir to lower the vehicle, or add more for the high setting, and to level the vehicle in the neutral and high setting to deal with varying loads. The Sport and Comfort modes also influence how the system distributes the hydraulic fluid to achieve a softer or harder ride. It’s brilliant in theory, but complex in operation, and replacement parts are expensive and exclusive to Toyota.

Our advice from Ironman 4×4 Africa was to keep things simple and reliable, as one should for an overlander, which meant disabling the AHC system and bypassing its electronics. We already knew our Cruiser was not handling well, was making strange noises over bumps, and though we could adjust ride height to some extent, the vehicle was sagging heavily at the rear. In normal trim, the 100 Series should be slightly nose-down. When we put it up on the hoist, we could evaluate the extent of the carnage. The shock bushes were gone, so they were riding on metal, and every one of the shocks was leaking fluid.

In with the new

Our suspension upgrade needed to deal with an estimated constant 200kg additional load from the aftermarket kit we intend to fit – including a drawer system, dual-battery set-up, fridge, body armour and a bullbar/winch combination up front. This meant going heavy-duty on the rear coil springs, and using Ironman 4×4’s thicker torsion bar up front.

We learnt that when installing a new torsion bar, and cranking it to achieve a lift of some 50mm above the standard ride height, one must be sure that 60mm of “droop” is still left in the suspension travel. This is measured as the difference between the bottom of the wheel rim and the wheel arch when the vehicle is at rest, and the point when the wheel lifts off the ground when the vehicle is jacked up. Less that this (because too much lift has been added up front) and all that downward force on full suspension travel will be transferred to the shock mount and shock eye, with predictable results.

Part of the standard Ironman 4×4 upgrade kit is a bolt-on L-shaped bracket that reinforces the lower control arms. This is a known weak point on the 100 Series Cruiser fitted with IFS, and when doing rough offroading with a reinforced torsion bar, the welds have been known to crack close to where the control arm pivots off the chassis. The reinforcing bracket sorts this out.

All this extra spring is nothing without control, and here we went for the best in the catalogue with Ironman’s Foam Cell Pro shock absorbers, front and back. These are massive in comparison with the standard shocks, and my father and I were like kids in a candy shop watching them being unboxed during the fitment process. These twin-tube shocks are heavy-duty in every dimension. It was great to see that the shock eyelets are machined from billet steel, then 360-degree welded to the shock body – strong construction compared to standard fare. The external body is 65-72mm wide, the shock walls are 3mm thick, and the 20mm piston rod is attached to a 45mm piston. The foam cell liner inside the shock prevents the aeration (and reducing damping) caused when the nitrogen and oil in a shock combine during hard use, as they can in a shock without such a foam layer.

The oscillations caused when driving on corrugated roads and during constant movement when off-road, causes a massive heat build-up, which in turn causes the shock to fade – it no longer provides damping and damage to seals often results. The huge oil volume in the Foam Cell Pro, some 2.5 times the volume of a typical OEM shock, helps dissipate that sort of heat far better, guarding against fade even under extreme conditions. This was music to our ears: the promise of comfort and performance during our adventures all over southern Africa’s most gnarly, rutted roads.

Other fitments

While installing the suspension, we started on the diff-breather kit. This is a prime example of preventative maintenance. Every vehicle has diff-breathers as standard, which function to vent pressure from inside the diff as it gets hot with use, and to allow movement of air when a diff suddenly gets cold, for example during a water crossing. The problem with OEM breather kits is they are often mounted too low on the chassis, and the risk is they could allow water to be sucked into the diff during water crossings, or become blocked and no longer breathe – which could lead to oil blowing out the diff due to a ruptured seal.

The Ironman 4×4 diff breather kit comprises longer reinforced, oil-resistant hoses attached to the differentials, terminating in an aluminium housing and brass breathers. This is mounted as high as possible on the vehicle’s firewall. The same kit can be used on gearboxes and transfer cases, which also have breathers, giving additional protection.

The final part of our phase one fitment was a snorkel, perhaps better referred to as a raised air intake. Contrary to popular belief, a snorkel isn’t solely for water crossings. It does help, but a snorkel is not there to make your 4×4 into a submarine. For that, you would need to do a lot more sealing of the airbox and all the joins. Rather, a snorkel’s actual function is to draw in cooler, less dusty air as far as possible from the road surface. The air intake on a 100 Series Cruiser sits in the right-hand front wheel arch, right in the dust zone. With the intake raised, we expect the air cleaner will stay cleaner for longer, which is good news for the engine. Apart from that, there is a more throaty intake roar, and our dark green BOB now has an added feature that makes it look like the serious overlander we have in mind.

With phase one of our modifications done, we are pleased with how our Budget Overland Build is shaping up. The suspension upgrade was a crucial modification, and it made an immediate impact on how the vehicle behaves on- and off-road – not to mention the aesthetic appeal of the increased ride height and the improved stance.

Budget Matters

Equipment costs:

  • Suspension (Foam Cell Pro shock absorbers, heavy duty-coil springs, torsion bar/reinforcement brackets): R28 300
  • Diff breather kit: R1 550
  • Snorkel: R4 700

Fitment costs:

  • Suspension: R2 840
  • Diff breathers: R575
  • Snorkel: R1 900

CONTACT: Ironman 4×4 South Africa head office: 011 634 7770 | www.ironman4x4.co.za

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