Rubber Drive Belts to crack and deteriorate
Rubber Drive Belts
always stretch a little in use, because of the strains put on them by driving the water pump and generator, as well as the fan itself if it is in the system. Age and continual flexing also cause belts to crack and deteriorate.
Stretching slackens a belt, so that it slips on the pulleys. A cracked belt will eventually break. The tension and general condition of the belt should therefore be checked at least monthly.
The ignition light comes on to give immediate warning of a broken belt, as the generator stops working.
But the first warning of a slipping belt may well be overheating of the engine or a flat battery — or both.
The belt often starts to slip only when the load on the generator is heavy — for example, when the headlights and rear-window heater are both on — and it becomes more difficult to turn. The fault does not show on the ignition light, but the battery is not getting its full charge and will eventually run down.
Overheating is caused by the slipping belt failing to drive the fan or the water pump properly.
Apart from these effects, a slipping belt is itself worn more rapidly by the heat generated as it slips. The inner face usually cracks first.
A belt that is too tight puts an extra strain on the generator and water-pump bearings, and often causes the premature failure of these bearings.
Before checking a belt always remove the ignition key, to avoid any possibility that the engine might turn over and injure your fingers.
You can make a reasonable check by looking carefully all round the belt, and by feeling around the inner face for damage. To check thoroughly, take off the belt and bend it back a section at a time, so that any cracks there may be are opened and easier to see.
Cracks, scuffs, tears and bumps anywhere on the belt mean that it must be replaced. The Vs of the pulleys in which it runs should also be examined, to make sure they are not the cause of the damage. They must be clean, smooth and free from the slightest distortion, as well as perfectly aligned so that the belt does not suffer from twisting.
Any misalignment is usually caused by mounting the generator wrongly.
Occasionally a high-pitched squealing sound is made by a belt that is loose or out of line. The sound may vary with the speed of the engine.
Do not try a makeshift cure by lubricating the belt with oil. Doing so will damage the belt and cause it to fail and a belt swollen or sticky with oil may still squeal, even after the original cause has been properly corrected.
A broken belt, though indicated through the ignition light, can still do much damage in a short time.
The flailing ends can tear out electrical cables, cut hoses or even damage the radiator. So switch off the engine as soon as possible if your V Ribbed Belt breaks.