MOTOR REVIEW

Hawera Star, Volume LIV, 4 May 1935, Page 14

MOTOR REVIEW

—:Qars and Their Upkeep —

Symptoms of Wear and Tear in a Used Car

IN the ease where a second-hand car is offered for sale without any special and valid guarantee as to its mechanical condition, the prospective purchaser must either buy “a pig in a poke” or have the working parts cai’efully checked by a capable mechanic. The minor defects are not of gre.at importance, for the the cost of putting them right will not add greatly to the unoriginal price, but the buyer must be on guard against serious 'vi'faults, which will either immediately or within a few months saddle him with a disconcerting bill for repairs.

A tolerably accurate idea of the condition of the engine can be obtained by the customary simple tests:, such as checking the compression by means of the starting-handle, listening for noises at idling speed, and taking the model for a trial run, during which the acceleration, behaviour of the engine at high, speed, petrol consumption, and other characteristics, are noted. It is not Suggested that a layman’s inspection is ordinarily satisfactory; notwithstanding that the examiner might have a ..good,'' general knowledge of car mechanics, but sometimes the buyer is so enthusiastic that-he is not willing to wait for an expert overhaul, fearing that he might lose a bargain because of such delay.

movement of the wheel, and if the amount of play is demonstrably greater, further probings should be made. Where there is an exposed propeller shaft, the extent to which the jacked-up wheel can be rotated before the shaft begins to turn can be noted, and the play in the various parts of the transmission estimated.

If, for instance, the wheel can be turned through half the distance of its total "free arc” before the'propeller shaft is moved, it is evidence that the backlash is more or less evenly divided between the rear axle gears and the universal .-joints.

Another helpful test which can also be conducted is to rock the wheel at the limit of its free movement so as to detect any loose keys or* other parts. The wheel-rotating test is also a guide to the state of the differential, but to conduct this trial the gear lever should be in the neutral position. The wheel is spun round by hand, and as the opposite wheel is resting on the ground and held securely, the differential pinions will rotate, and excessive wear or damaged teeth will be - revealed by the noise emitted. By turning the wheel slowly, the observer will be able to note any stiffness, which sometimes promotes a dull, grinding sound. If any of the symptoms mentioned are detected, it would be best to have the parts dismantled and examined.

- Assuming that there is no need to suspect the car offered 1 and that the engine gives a good account of itself during a short road test, it is wise to consider what other "catches” might exist.

It is for the most part a matter of wear and tear, and particular attention should be given to the king-pins, brakes and transmission. Only a deliberate examination will reveal the shortcomings of those parts, and since new gears and crown wheels are expensive, every simple precatuion should be taken. Usually the accurate estimate of the wear in the transmission efin be obtained without stripping the chassis. The following is the procedure advised by a competent authority: Jack up one of the rear wheels, and with low gear engaged rotate the wheel until the resistance of the engine compression is felt. In that way the total backlash in the transmission can be ascertained. The permissible margin should not exceed 10 degrees

Neglect of rear-axle lubrication is a fruitful cause of harm, and the owner should be careful to use the grade of lubricant advised, to inspect the level of the "diff.” from time to time, and to drain, clean and refill it after each 10,000 miles running.