The Major Service

In nearly thirty years of vehicle engineering, requests for a brake fluid change could be counted on two hands. It is the one that matters most.

So as not to split hairs and go down two very close but parallel roads, the full and major services are treated here as the same thing — different people simply use different terminology.

From the previous article dealing with minor servicing, there were several items that required checking rather than replacement, notably spark plugs and the air filter. During a major service operation these two items tend to be replaced as a matter of course, purely because vehicle parts do deteriorate over a period of time irrespective of the miles covered. However, we must not lose sight of the benefits afforded by the latest generation of long life spark plugs, which incorporate platinum tipped electrodes and generally have an effective service life of around 50,000 miles.

Filters

Air filters do not have the same advantage. Their life is dictated by the air quality passing through the filtering elements, and usually the better job they do, the shorter their effective life.

On the subject of filtration, there are two other units which should be changed, or in one case inspected and changed if required. The fuel filter can have an enormous effect on the way a vehicle runs and is ignored at your peril; as with any filter device it has a finite life, and once past a certain point it simply cannot remove any more impurities from the fuel, leading directly to poor performance and rough running.

Not quite so important is the cabin, or pollen, filter. This device simply filters incoming air for the vehicle interior, and again its effective service life will depend on the quality of air being drawn through it. From past experience, vehicles have come into the workshop with the owner convinced that a lack of ventilation will involve the removal of the entire dashboard assembly and its accompanying large labour bill, only to find that the culprit is simply a clogged cabin filter.

Brake fluid

The main reason for changing the brake fluid every two years is that it absorbs moisture from the atmosphere. Once the moisture content exceeds a certain level and is subjected to temperatures exceeding 100°C, that moisture will boil, forming steam pockets in the brake system.

Now go back to school science lessons: liquids are not compressible, but gases are. That compression is provided by brake pedal action, leaving you, the driver, with a pedal that goes nearly to the floor without having any braking effect.

Coolant

No matter how long you leave changing the engine coolant, it is unlikely to cause you and your passengers any physical harm, as in the ancient brake fluid scenario. However, serious damage can occur to your finances due to corrosion within the cooling system in the long term, or more catastrophically, a frozen engine in the short term. Draining and flushing the cooling system then refilling with a 50/50 mix of water and antifreeze will help address the above, and should be carried out at two year intervals.

As with all maintenance procedures, the objective is to address the deterioration which occurs during use, and the content of these procedures should be calculated according to that use — hence the regular oil changes, the inspection of brakes, steering and suspension, all the way through to the biannual changing of brake fluid and engine coolant.