Want to avoid a breakdown and cut down on expensive repairs? You have to take action We know from the AA that the number of models and complexity of modern cars mean that there are a huge and varied number of things that can go wrong at any time. So where do you start? We asked the AA to tell us about the most common faults they come across; here’s a brief run down on what they are and what you can do to stay safe on the road and avoid expensive repairs:

Flat or faulty battery

Most common problems are caused by terminals and clamp connections or by a loss of voltage, often caused by constant use on short journeys without regular recharging. At every service, check that the terminals have been cleaned and protected from corrosion with a layer of petroleum jelly or grease, and that clamps and connections are secure. If you don’t make long journeys, a fortnightly overnight charge prolongs battery life; modern maintenance-free batteries don’t need a top-up.

Lost keys

Most modern cars have a ‘transponder’ key combining a conventional mechanical key with an encrypted electronic chip to prevent theft, which means if you lose the key, recovery to an authorised dealer may be the only answer. As it might take several days to get a replacement, you should always carry a spare key. Flat/damaged tyres and wheels You manual will tell you what the correct tyre pressures should be and you can adjust the pressures to suit different speeds and loads. You should check the pressures once a month – don’t leave it for the mechanics to do at your annual service. When checking tread depth, look out for uneven tyre wear – it’s possible the wheels may be misaligned and you should consult a tyre specialist for advice. And don’t forget the spare tyre. A worn or flat spare won’t help you in an emergency. Finally, check that the jack is in good condition and that the key/removal tool for the locking wheel nuts is accessible.

Alternator faults

Persistent battery problems and dim headlights when the engine is idling can indicate alternator/generator faults. Belts driving the alternator may also operate the radiator fan and water pump. A red ignition warning light, plus a rapid rise in engine temperature, could indicate a broken belt, in which case you need to stop straight away and get assistance.

Starter motor

Though usually robust, starter motors can fail. A regular service should highlight potential faults.

Fuel problems

Empty fuel tanks cost a lot of time and inconvenience. Fill up at the start of your journey and well before the warning light comes on. Don’t drive on fumes. Every year more than 150,000 motorists put the wrong fuel in their car – petrol in diesel is most common but drivers put diesel in petrol cars too. When that happens you’ll need to drain and flush the fuel out of the system before filling up again.

Clutch cables

Clutch cables are under high stress, and abrasion can weaken the wire strands until they break. Temporary roadside repairs can be made, but replacement at the first signs of wear is the best solution.

Spark plugs

The spark plug is a much-neglected part of the ignition system. Make sure that the plugs are replaced at the manufacturer’s recommended service intervals.

High Tension leads

High-tension (HT) leads and their connections can deteriorate with age; water and dirt enter cracks in the insulation, reducing ignition voltage. Damp-repellent sprays like WD-40 are only a temporary solution. You should ask your garage to check the condition of the leads and replace as necessary.

As you can see, there are only nine top faults, so we thought we should make it a nice round TEN by adding this tip: don’t forget to read the manual. It tells you everything you need to know about your car and can help you become more aware of any small niggles and stop them becoming expensive problems.