4WD MODIFICATIONS – SUSPENSION & BRAKES
Very few standard suspensions are suitable for bush work; we guide you through the maze of aftermarket suspension choices. We also cover the important topic of brakes.
The reason not a lot of effort is needed when braking is your vehicle’s brake booster that amplifies the force your foot applies to the brake pedal. A more powerful booster can improve braking performance.
Toyota’s 70 Series braking has never been very good and its handbrake very quickly becomes useless unless mechanics are careful with set-up and adjustment.
Bendix’s Ultimate 4WD Big Brake Upgrade Kits deliver improved braking performance for some dual cab utes and wagons.
Most 4WDs spend their time relatively lightly loaded around town and fully loaded on bush trips. Trying to make a fixed-setting shock absorber handle both damping tasks isn’t easy: hence, the adjustable shock absorber.
Supple suspension gives great wheel travel and a comfortable ride, but load and road conditions can sometimes cause ‘bottoming’. There’s a procedure to control this undesirable situation.
Like many people, we at OTA have had the broken U-bolt experience. Our trailer U-bolt incident didn’t result in an accident, just temporary axle misalignment, but other people have been less fortunate.
Raising independent-suspension front ends is fraught with difficulty and often results in misaligned wheels and excessive suspension component wear. Replacement upper control arms promise to remedy that situation.
Heavily loaded utes are common sights on bush roads and tracks. Braking power could do with an improvement we’ve reckoned for some time and Pedders agrees with us.
Many of us are familiar with the design of off-road-race shock absorbers, with their external ‘bypass’ tubes. ARB’s BP-51 bypass dampers use the same principle, but with internal bypass technology. They’re vehicle-specific and new models are being added periodically.
We asked the Australian Koni distributors, Toperformance Products, for a set of dampers to test on our LandCruiser 75 Series, but they refused, so we’ve used OTA Team vehicles for the purpose.
At Outback Travel Australia we’re big fans of monotube shock absorbers. All our testing over the past 20 years shows that they have better bump and rebound control than twin-tube types, run cooler and fade less.
We fitted a test set of Bilsteins to the Outback Travel Australia LandCruiser 75 Series and did 10 major bush trips at a full 3.5-tonnes GVM on some of the worst roads and tracks in the Outback.
Dobinsons has a range of MRR monotube remote reservoir shock absorbers. All are re-buildable and re-valvable, and are direct bolt-in replacement units.
Bilstein shock absorbers are well known for their high-performance damping abilities on 4WDs and there’s a revalved range to suit single and dual mounting on caravans and camper trailers.
After bar work and roof racks the most common modification made to a 4WD is done underneath – to the suspension. We’ve separated different suspension types and listed the ideal changes needed for each type.
Apart from air-suspended 4WD wagons we can’t think of any stock 4WD that won’t benefit from suspension modifications that can improve load carrying capacity, off-road ability, ride quality and handling