If your vehicle breaks down out the back of beyond you have two options: you’ll have to either tow the vehicle out or fix it on the spot. With one or more companion vehicles you have the option of towing or driving a vehicle or vehicles back to get parts to fix it. With only one companion vehicle you will have to consider whether the 4WD going out by itself can indeed make it and return safely. If you are by yourself and haven’t got the necessary equipment or skill to do the job, you will have to call or walk out for help.
DON’T JUST TURN THE RADIO UP!
An integral part of knowing your 4WD is being familiar with what it sounds like when the motor is idling, when you are driving on the road and when you are tackling more challenging situations off road. If you become aware that the sounds have changed try to figure out why. Don’t just turn the radio up louder! Investigate all noises and vibrations at once. If you leave them, further damage could occur which you may not be able to fix yourself.
SIMPLE BUSH REPAIRS
The following hints may get you out of trouble, but I must emphasise that proper repairs should be made at the earliest opportunity.
Before attempting any emergency repairs sit down, have a cup of tea and consider all the options. Work out the best way to proceed in advance or you may find yourself in a worse situation.
A flat battery is always a nuisance but if you were on your own miles from anywhere and out of cellphone range, the situation could become very nasty.
It is possible to drain current from a battery in a short time, to the extent that there is not enough power left for that most vital of all jobs – starting the engine. Without the correct electrolyte level batteries won’t work efficiently. And unless the alternator and voltage regulator do their jobs properly the battery won’t receive the proper charging. If you leave items that use electricity switched on, without replacing in some way the power being drained, the battery will eventually run flat.
Some current 4WDs have complex computer-controlled ignition systems and electronic engine-management systems. Starting them with assistance from another battery, or ‘jump-starting’ them in the wrong way can cause expensive damage to expensive components. This is where the proper workshop or service and repair manual can be invaluable – refer to it for your vehicle’s electricals.
Back to the problem you face: how to get the engine started when the battery is flat. There are two practical ways to do this: jump-starting and clutch starting.
A vehicle battery has two terminals to which leads are connected. They have a positive (+) redcoloured lead and a negative (-), usually of plain black lead. By connecting jumper-leads, from the rescuer’s (good) battery to the flat (bad) one, electrical current can be transferred to start the engine.
As a general rule (and this is correct for the normal diesel, as well as petrol engine), all it takes is to connect the positive terminals together with the red jumper lead and connect the negative terminal of the assisting vehicle to a substantial earthing point on the disabled vehicle with the black jumper lead. Start your vehicle while the rescue vehicle engine is running at a fast idle, and then keep the engine of the disabled vehicle at a fast idle when it has started.
Leave both engines running for several minutes so the good battery can boost the bad one. If you disconnect too quickly the bad battery may last only a few seconds before dying again and killing the engine. Diesels do not have this problem of keeping going because they don’t use any electricity from a battery for ignition.
If your jumper-leads are pencil-sized in diameter they will not be able to carry the current necessary to jump-start a big engine. If the battery clamps are cheap and simply crimped onto the cable this can cause a lot of resistance, which causes heat. Effort is lost when the cables and clamps get hot, and the needed current does not all get from good to bad battery. For safety, buy a pair of heavy-duty cables, rated at 400 amps or better, with big heavy-duty insulated clamps, and carry them in your 4WD at all times, especially if it has an automatic gearbox. Two pairs of thin leads in parallel may get you out of trouble.
In this case the vehicle depends on being mobile in some way to develop the effort needed to turn the engine over and make it start. (If you have a 4WD with automatic transmission, skip this section, because you cannot clutch start your vehicle.)
When your 4WD is in gear with the engine running and your foot off the clutch, the engine causes the wheels to turn. In essence, what you need to do to start your engine by clutch starting is to do exactly the reverse of this, and make the wheels turn the engine.
The simplest way to clutch start your engine is by rolling down a hill. Turn the ignition key to ‘on’, (the accessory position is not enough), put the gearbox into second gear high range but keep the clutch pushed in. Let the parking brake off, and when your 4WD is rolling at about a fast walking pace, let the clutch out. The rear tyres (assuming that you are not in 4WD) may protest a bit as they are forced to turn, but when they do they will cause the engine to spin over and hopefully start. Keep a good eye out for any onlooker who might get in the way.
The reason for using second gear is purely mechanical. In first gear the downhill motion, with tyres trying to turn in the dirt, may not be sufficient to overcome the compression resistance in the engine cylinders. In second gear the mechanical leverage available to turn the engine is better, and the engine will spin faster as well. Actually, you could probably roll start your 4WD in any gear, because it simply depends on vehicle speed at the time you let the clutch out, but second gear has been found to be the best overall. The lower the roll speed the less the risk, yet it still gives enough mechanical advantage for starting.
You may need a little acceleration or choke to help the engine get ample fuel for starting. If it won’t start cleanly push the clutch back in, and try a little more rolling speed before letting it back out, to try again. (If it won’t start after three or four good tries, you may have a more difficult problem than a simple fail-to-start.)
When the engine does start, push the clutch in and brake to a safe stop, keeping the engine going at a fast idle. Most current types of alternator will usually produce charge providing your engine is doing more than 1000 rpm. If your 4WD has a hand throttle, set the revs about 1200-1500, and leave the engine runing for half an hour, which should give enough power to re-start with the starter motor.
Other alternatives to rolling your 4WD down a hill to start are to be pushed from behind by people or another vehicle; to be towed from in front by another vehicle; or to do just what you would forwards, but instead go backwards using reverse gear.