Sticky brakes: avoiding the drag
Many drivers’ worst nightmare is brake failure. The fear is justified; it is a terrifying situation. Yet, brakes that do not release fully can be just as lethal.
Friction brakes convert motion into heat, which is shed into the surrounding air. Should the brakes ‘stick’ (or ‘bind’), they are not releasing fully and the braking system then overheats. Many drivers may be familiar with an overtaking manoeuvre involving an HGV, for example, being followed by a pungent aroma of burning friction linings.
Yet, the situation poses a higher safety risk than a ghastly stench. In all but minor cases of binding, the surrounding airflow cannot remove enough heat, making the brake on the affected wheel work less efficiently, when the driver depresses the centre pedal.
In severe cases, the brake fluid might overheat and boil, causing total brake failure. Heat can also transfer and affect the wheel bearing. Should it fail, either the affected road-wheel can seize, or even become detached.
Most binding issues are caused by corrosion, promoted by low speed, infrequent trips, or poor maintenance. Long periods of the car standing idle, usually with the park-brake applied, do not help.
Therefore, make regular checks that your brakes are not binding. You can do this without leaving the driver’s seat – although do so with due deference to your surroundings. When you release the brake pedal on a slight incline, check that the car moves without resistance virtually immediately. Another check you can perform is to touch the metal wheel rim after a journey but do not poke inside the slots and holes and certainly do not touch any of the brake components.
Should you notice that the temperature of one road wheel is higher than the one on the opposite axle, you may have found a binding brake. In these cases, consult a vehicle technician as soon as possible.