BRAKE ADJUSTMENT

Shannon News, 5 October 1928, Page 1

BRAKE ADJUSTMENT

CAUSES OF FAILURE. As traffic congestion increases and motorists arc required to make rapid acceleration to get clear of city traffic crossings, tlie question of acceleration and braking is becoming more and more important. Slow-moving traffic at street intersections increases the inconvenience of both pedestrians and other road users, and the brakes, therefore have more demands place's upon them than previously. Theoretically the- proper method, to pursue when, adjusting brakes is to load the body with bricks or other weighty material, so that the springs are unoer the approximate compression as when passengers are carried. This makes provision for any axle movement due to loading,, and brakes so adjusted will be more satisfactory. Brakes having been properly adjusted, other factors arise which, in some uesigns, are likely to cause temporary inefficiency. In wet weather water splashed into the brake shoes reduces effectiveness, because water acts as a lubricant. The'water may be evaporated after a few applications of the brake, but the temporary ineffectiveness may lead to an acciaent. After considerable use, during which brakes have been readjusted, ineffective braking may result through the change of the angles of the bell cranks. The correct setting which gives full power for the brakes requires the bell cranks to stand at right angles to their pull-rods, as it is only in this posiuon that the maximum braking power is obtained. The angles of the bell cranks may alter-through stretching of the brake cables, as well as through the adjustment on the brake rods or cables. If the car is old and the wheel bearings need adjustment, the lop or the bottom of the brakes may become burnt, and thus, through the reduction in braking surface, they lose their efficiency. Brake drums sometimes become scored through the rivets, and when this occurs reduced cffectivevness results.

The brake surfaces may become less effective through charring, which results ultimately in glazed surface, and a similar result can be created through leakage of lubricant into the brake shoes, or through road grit or dust becoming embedded in the lining. It is quite possible that glazed surfaces“will reduce braking efficiency by 30 cent. If rivets are allowed to «ome into contact with the brake drum, thus reducing the contact of the lining with the drum, brakes which were once very efficient will be found most inefficient. On cars that have been badly driven the brake drums or bands may become mis-shapen. Brake drums may become eccentric, and an error of 100th part of an inch may cause brakes to lock momentarily. Rusty linkage and lack of lubrication may cause brakes to work weakly and fail to come off when the brake pedal is released. Brake shoes working on an anchor braeket or pivot may have free movement reduced through dirt. When brake linings are renewed, it is a good plan to run the car in first or second gear for a shoxt distance with the brakes applied, so that the lining will be heated to just below smoking point, and then give a final adjustment. Brakes and their mechanism usually receive little attention beyond tighten ing, the user forgetting that there is a good deal of mechanism in the brakes themselves, which needs periodical cleaning, oiling, and, in due course, re nowal. Brake drums receive more stresses and wear than any other part of the car’s mechanism, for the reason that the brakes work under dry conditions, and there must be friction for proper operation, and where friction exists wear and stresses are unavoidable.