When the time comes for a vehicle’s check mot examination, the same things tend to result in failures, year after year. Although there are easy ways to pre check cars and vans for common faults, not to mention free professional help available, it seems that drivers either forget to carry these out or assume that they’d have noticed anything wrong. While this is sometimes true, the fact is that many common caused of MOT fail can go unnoticed. A substantial 1 in 10 failures, for example, are caused by faulty brakes, which in the vast majority of cases could have easily passed by following sensible advice.
On modern disc brakes, the lifespan any motorist can expect from a new one varies quite considerably; it could be anywhere between 25,000 and 60,000 miles. Although pads vary in quality and durability slightly, such a wide variation cannot be explained by differences in the actual products. Other factors come into play over the lifetime of these pads, from environmental factors to the way vehicles are driven. As replacing a worn brake pad costs on average about £100, any sensible vehicle owner will surely want to know what they can do differently to ease their wear and tear. Of course, inadequate brakes are also dangerous, and sure to cause a check mot fail.
If a brake pad becomes worn over all or part of its surface, there are safety features which automatically come into play. The first thing a driver might notice is an unusual sound while driving, not braking; this will be a squeal coming from the affected wheel. Once the brakes are applied, however, the noise will stop. In fact, this noise is engineered into the brake pad, in the form of a metal tab which deliberately rubs against the disc when the pad is worn, thus emitting the warning noise. As soon as this becomes apparent, the pad should be examined (and very probably replaced).
Another telltale sign of worn brake pads is a feeling rather than a sound. When applying the brakes, the driver might notice that the brake pedal shakes slightly underfoot. Although this can be quite worrying, it is often the result of products used in brake pad design rather than a major fault in the product itself. Pads are kept in place by a strong resin, which can melt and become displaced when brakes are too heavily used, too often. When the resin comes away from the pad, it can get smeared onto the disc, but not in an even pattern. This is called glazing, and makes the pad lose its grip on the glazed parts of the disc, rather than gripping properly.
It is often the case that brake pads exhibit wear unevenly, and certain pads wear out quicker than others around the vehicle. This can manifest itself with a “pull” in one direction when braking, as one brake pad gets a better grip of its rotor than its partner on the other side of the vehicle, especially on the front wheels. This can be a sign that the metal pad itself is worn, due to friction with the disc; this is the worst type of wear, and should be remedied immediately. If a pad is worn, it cannot create enough friction with its disc to slow it down as it should, meaning the vehicle is actually in a dangerous state.
Driving in urban traffic often damages brake pads the quickest, although this can be partly the driver’s fault. Some drivers tend to get frustrated and make up space as quickly as they can when the lights change, meaning they then have to step on the brakes at the next junction. Every time brakes are applied excessively, this creates heat between the pad and disc, which the pad has to dissipate at the same time as slowing the vehicle. This is a double measure of wear and tear which is totally unnecessary.
Carrying extra weight also means brakes have to work harder. As well as obvious steps like emptying shopping and luggage as quickly as possible, it’s worth remembering that customisation work often comes with extra weight. Similarly, speed limits are designed for a reason; part of this is to give motorists plenty of time to brake safely. The more distance a driver has, the less pressure is needed on the brakes, and the longer they will last. Simple habits like this make the roads safer and also save motorists money on brake replacements.