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Driving a 4x4 offroad is an acquired skill. Think safety at all times. DON'T TAKE RISKS. Practise techniques first before having to use them in earnest. Better still, learn them correctly at a 4x4 off road centre. Advice here is biased towards environmentally friendly UK codes of conduct. On a serious 4x4 expedition overseas, vehicle safety may take preference over environmental issues. Your life may depend on it.
Deep Ruts and Ditches
Be aware of your vehicles ground clearance and location of its lowest points. Allow wheels to follow their own route inside a deep rut and avoid over steering. Grip the wheel lightly but be prepared to take firm control if necessary.Cross ditches at an angle, never direct on. Learn about your vehicle's approach and departure angles beforehand.
You need to check for submerged objects, underwater potholes and whether the bottom is solid or soft mud. If you can't see bottom then walk where the left tyre will go and return by where the right tyre will go. Sideways currents can affect directional steering. Turn off air con. If the water could reach the cooling fan then it's best to switch off the engine and let it cool. That way an electric fan won't start up in the crossing. Rotating fan blades can bend in the water and damage the radiator. Remember your tyres act as floats, lowering the pressure your vehicle puts on the ground. It's therefore easier for the vehicle to be pushd sideways.You are usually safe upto the hubs and probably upto the door sills. Go slow and steady pushing a bow wave infront. The wave causes a lower water level inside the engine bay. Nurture the wave. Don't stop or accelerate through it. Keep the engine running; if water enters the exhaust it's very difficult to re-start. Check braking after leaving the water. Light pressure on the brake pedal whilst driving a short distance will dry brakeshoes and drums. Discs are quicker to dry out. If the water was muddy then brake drums should be removed and cleaned out when possible. If the axles were submerged they may have sucked water in through the breather valve or oil seals when they suddenly cooled.All breather tubes should be raised up above possible water level if you intentionally go deep water crossing. It's a good idea to let hot axles cool before entering cold water.Changing the oil is cheaper than changing the diff and bearings.|
Well fitted snorkels are needed in deep water but all electrics in the engine bay need to be waterproofed also. In emergency, with no snorkel, a radiator blind can be made from tarpaulin. The idea is to stop water passing through the radiator and guide it under the engine. Keep the tarp clear of the wheels and tie it back behind the engine bay securely, avoiding the hot exhaust. If you stall the engine in water you may need to dry all electrics before it will restart, otherwise, cranking the engine in gear will move the vehicle forward or backward.
Eyeball it first, walk it if possible. Pick the easiest route avoiding rocks, stumps, holes etc. Check for problematic departure and approach angles. What is at the top of the hill? Tie everything down inside.Select your gear. Go for a steady pace, use as little accelerator as possible but enough to avoid stalling. Stay on the power but if a wheel spins, back off the power a little to get traction again. If you stop on the hill, apply brakes and clutch and immediately select REVERSE. Release the brake and engage the clutch fully. DO NOT BRAKE on the way down. If the wheels lock you'll lose steering and slide sideways and maybe roll over. Reverse down the hill in gear in the straightest line you can WITHOUT BRAKING. The engine will brake safely for you. You can safely back down a hill far too steep to climb without braking.
Use engine braking to slow your descent down a hill not the brakes. If the back end starts to slide around then ACCELERATE slightly to re-gain control. If you brake when driving down a hill and a skid develops EASE OFF THE BRAKE. It goes against instinct but you will gain traction again and therefore be able to steer. Wheels must be turning to be steerable. If the vehicle turns sideways it will probably roll.
This can wrap around the crank pulley, block the radiator, catch fire on the hot exhaust and hide the most amazing obstacles and holes.
Progress ultimately depends upon the tread on your tyres. The more aggressive the tread, the more likely you are to reach your destination. Even the most aggressive treads cannot cope with wet clay. Turning the steering left and right will often find a bit more grip when progress is about to holt. Steady momentum is again the key to success, frequent gear changing and acceleration are not. You can lower tyre pressures by half, in the same way as driving on sand. Braking should be checked after driving deep mud. Remove mud from your vehicle to prolong chassis life. This is where pressure washers are useful!
Generally, large rocks should be hit squarely. The most vunerable part of a tyre is the sidewall, you need to avoid cuts scratches. Slow steady progress in low gear with your foot off the clutch pedal. With manual gearboxes, brake only if essential.Automatic boxes give less engine braking so you may have to brake gently on the down side of a rock. It's easier to maintain a slow steady momentum than to start off again after a stalled engine. You need to know where all your wheels are and where they will be a few feet further on. Pick a course to avoid getting high-centred. If in doubt, move a rock or pack smaller ones near it.
Moist or wet sand is not a major problem. If you can see tyre patterns then the sand is firm, but if tyre tracks are narrow vees then the sand is soft. Check that there isn't mostly dry sand just below the surface. If followinga vehicle which is breaking through a thin crust, don't follow in their tracks, drive your own crust - less chance of loosing critical momentum. The golden rule in soft sand is to MAINTAIN MOMENTUM, AVOID BRAKING and SHARP TURNS. When starting off, do it slowly, even slipping the clutch if necessary -in automatics use 2nd gear. Never change gear or slip the clutch when under load - you will come to a stop quickly. You may need a running start to get the required momentum but you should be in the highest gear that will do the job but we are not talking SPEED here. Reducing tyre pressures by half reduces the requirement for momentum.This is where compressor air pumps are useful! A spinning wheel will dig the vehicle down to the chassis in seconds. If you come to a stop, get out and take a look first, you may need a recovery technique, don't try to power your way out. On sandy steep descents accelerate out of a slide don't brake. Drive straight up or down a dune, don't traverse it and don't drive blind over the top of one. Desrt terrain is most easily judged when the sun is low or when the spot lights are placed high on the vehicle. Don't drive through a sand storm - park the vehicle downwind and sit it out. Drive corrugations at the best speed to minimise vibration. If you drive sand regularly, invest in a long handled shovel.
The secret is to use a low enough gear to keep the engine revving happily, to maitain momentum and avoid changing gear unnecessarily. Remember snow can hide rocks, branches, frozen streams etc. Drive the crown of the track, leave a wide margin for ditches and keep to the high side on a slope.
Turn the steering left and right if climbing and you begin to loose traction. Don't change gear on ice. Drive down a snow slope don't coast down, then you will maintain control.
Driving through slush in freezing conditions can cause ice to build up around the steering and suspension. In remote areas in winter it makes sense to plan for overnight survival.
Care for the land you drive over. Don't use more aggressive tyres than is necessary, lower tyre pressures on fragile land. Don't make tracks, follow the ones that exist. Four driven wheels spread the traction effort needed and are less damaging than two driven wheels. Don't travel in large groups and be aware of the interests of wildlife.