Haynes seriously useful info

The Seriously useful info series

Although many car owners believe that modern cars are too complicated for them to work on, this is not so. Routine tasks can be done by anybody - if they know what they are doing.

With the Seriously Useful Info series, our mission is to give you a greater understanding of your car and provide you with essential tips, advice and tasks that will aid trouble-free motoring. For example: how to check tyres and engine fluids, replace wiper blades, light bulbs and spark plugs, how to conduct a pre-MOT test check and what to do before taking your car on holiday or abroad.

Links to the other Seriously Useful Info features appear at the bottom of this page.

How to avoid the won't start nightmare

Haynes - car battery change Few things are more instantly depressing than a car that will not start. You turn the key in expectation and are rewarded with - nothing! Battery failure is the number one reason motorists call a breakdown service. And it is just one of many common faults that are caused by a lack of basic maintenance.

Of course, having your vehicle serviced regularly is important but it does not stop there. Over the past ten years, manufacturers have increased the service intervals, therefore there is an even greater need to carry out safety and maintenance checks in between these long periods. Carrying out such checks will help avoid unwelcome bills and minimise the expense or the inconvenience of a breakdown.

Although many car owners believe that modern cars are too complicated for them to work on, this is not so. Routine tasks can be done by anybody - if they know what they are doing. Haynes, the world-leading publisher of automotive repair manuals, is renowned for teaching millions of car owners how to carry out routine maintenance and repairs. The manuals provide authoritative and accurate step-by-step information for both basic and more complex tasks.

A flat battery and how to replace it.

Modern car electrical systems put big demands on the battery. Sometimes a battery will fail with no warning, but usually the first sign of trouble is that the engine is reluctant to start when cold, with the starter motor turning more slowly than usual. This is then followed by a failure to start at all.

There are three main reasons for a battery to be flat. One is old age, in which case fitting a new battery will cure the problem. The second is leaving the lights on (or even the radio or alarm, if parked for a long time); generally a jump-start will put things right - although the life of the battery will be shorter following a complete discharge. The third is a problem with the charging system; fitting a new battery won't cure that.

A Haynes Service and Repair Manual gives simple tests so that you can identify the reason for your flat battery.

Replacing a Battery

You'll need a new battery of the correct size and capacity to fit your car. If you plan to use it straight away, it needs to be charged - ask when you buy it. Buy some copper grease or special battery terminal corrosion protector spray too.

Warning: Batteries contain sulphuric acid, which is poisonous and causes burns; they give off hydrogen gas, which is explosive when mixed with air; when charged they contain enough electrical energy to cause burns or fires if short-circuited. Follow all precautions specified by the manufacturer.

Disconnect the electrical leads from the old battery, negative (earth) first (look for a '-' sign near the battery terminal). Undo the fixing clamp nut or bolt - details vary for each car - and lift out the battery. Be careful not to drop it, and keep it upright to avoid acid spillage.
Fit the new battery, secure it with the clamp and connect the electrical leads, negative (earth) last. Protect the terminals against corrosion by smearing them with copper grease or using an anti-corrosion spray.
Check that the negative (earth) lead connection to the car body is clean and tight. Unbolt it and clean it with a wire brush or abrasive paper, if necessary.

For more advice on model-specific procedures, please refer to the appropriate Haynes Service and Repair Manual. Haynes Manuals are available from this website and all good car accessory retailers and bookshops including: Halfords, Motor World and WH Smith. Please use our comprehensive Stockist Locator in the left margin of this page.

Haynes Hints
	A slack or broken alternator drivebelt can cause the battery to go flat. Using a mains charger on a failing battery will sometimes help it keep going for a little longer. Most modern batteries are sealed for life, so you can no longer check or top up the electrolyte level. Dispose of the old battery responsibly - don't just put it in the household rubbish. The lead it contains can be recycled.

Seriously useful info features....

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