EFFICIENT BRAKES.

Auckland Star, Volume LXII, Issue 194, 18 August 1931, Page 15

EFFICIENT BRAKES.

CORRECT ADJUSTMENT.

A DRIVING ESSENTIAL.

INTERESTING TESTS.

The importance of correct adjustment of four-wheel brakes was recently demonstrated by tests conducted at the National Physical Laboratory, London. A working model of a car was used in the experiments. It was found that the model skidded perfectly straight for 4ft with all four brakes on and the wheels locked. With the two rear wheels locked the car skidded 9ft forward, and deviated lft to one side, whilst with the two front wheels locked the machine skidded sft forward and kept a straight course. With both front and the righthand rear wheel locked there was a skid of 4Jft and a slight deviation to one .

The investigation resulted in the following conclusions: —The tendency to overturn is specially marked at high speeds with the following brake combinations. Two rear brakes only in operation—a diagonal pair of brakes— and also when one front and two rear brakes are applied. In the case where the front brakes lock the wheels of a car, the driver has little or no control over the direction of travel so long ae those wheels are locked. On the other hand, when the rear wheels lock, the stability of the motion is better under control. These experiments indicate the importance of correct brake adjustment.

Now-a-days, with high speeds and mobile brakes becomes more important than ever. The standardising of fourwheel brakes has given to motorists greater control over their vehicles, but at the same time has introduced a more intricate braking system when it calls for adjustment. The appearance of so many black smears of rubber on the surface of city streets is only too significant of the number of cars that are running with unevenly adjusted brakes. Admittedly not all brake systems are easy to adjust correctly, and where there is any doubt in this respect it is advisable to let an experienced mechanic handle the job.

For those who desire to handle the adjustment themselves, the best way is to jack up both axles eo that all wheels are free of the ground at the same time; then cut a strut to press down the brake pedal from the dash or from front of seat, whichever ie the most convenient. Go to each wheel in turn and make the adjustment so that you can just manage to turn the wheel by using the whole of your strength. Compensated brakes present the greatest difficulty and may make it necessary to go the round of the wheels several times. This is becauso individual adjustments affect the other brakes. In carrying out such an adjustment it is well to remember that worn treads of tyres do not give the same road grip, ae do covere with the patterned tread in good condition; also that tyres should be evenly balanced as regards tread surface on the wheels of each oxle.