ROADSIDE TYRE REPAIRS

Evening Star, Issue 21945, 4 February 1935, Page 6

ROADSIDE TYRE REPAIRS

HINTS FOR MOTORISTS •Provided the walls of the tyres have not weakened or their treads worn down excessively, the motorist seldom meets with two punctures in quick succession. He can, therefore, generally content himself with the spare- wheel, leaving the repair of the damaged inner tube to the nearest service station. But those who tour in districts where public garages are few and far between should always carry one or two extra inner tubes and a puncture repair outfit. In the event of a blow-out or a puncture caused by a large nail or other sharp object the tyre deflates suddenly, and there is no difficulty in tracing tho source of the damage, but gradual deflation is often deceptive, and it should not be assumed that the inner tube is punctured merely because the tyre has subsided slowly overnight or during the day’s run. The nipple of the tyre valve should first be inspected. A deformed or displaced washer in the head of the nipple might have pressed down the plunger of the valve so that there is a slow but continuous escape of air. A faulty valve “ inside ” is another likely cause. It might be that the tyre was inflated with a pump from whose attachment grit and dirt had not been driven by giving a few strokes with the handle before connecting the pump to the tyre valve; so that a particle of grit lodges on. the small valve seating, with a result that there is a slow leakage. Sometimes, too, the base nut of the tyre valve loosens, so that the assembly is not a tight fit. When a tyre has not become deflated quickly it is often worth while to reinflate it partially and then test the valve orifice, when, if air is escaping, a bubble will form. Old inner tubes tend to become porous, and there may be a gradual drop in the inflation pressure not attributable to an actual puncture. For example, it often happens that it a -well-used inner tube is inflated to, snyv 351 b and the oar garaged for a few days, the reading will drop to 251 b or less. If wayside repairs are necessary certain precautions should be observed. After removal the inner tube should be carefully tested, preferably under water, to find if the leakage is from some part of the valve assembly or from a puncture. It any perforation is detected the spot should be marked with a pencil or by a scratch and the surrounding area carefully dried. The patch applied should be big enough to reinforce the tube in the neighbourhood of the puncture, but should not bo unnecessarily large. A vulcanised patch is naturally more satisfactory than one which is merely cemented, but if tho latter sort of patch is applied carefully it should withstand hard usage. The danger is that a poor . patch will lift when the tyre becomes heated. When the area near the puncture is dry the surface should be wiped with petrol applied on a clean rag and then roughened with glass paper or the scraper, which will be found in most repair outfits. The cementing solution can be put on, but should not be applied thickly, and should always be allowed to dry for several minutes until it becomes “ tacky.” To avoid any risk of grcnsincss it is best to spread it with a penknife or match stick, and not with a finger. The patch should be cut to size before its protective covering is peeled off, and should then be pressed on the puncture. It is a good plan to stretch the tube over some curved surface such as a mudguard, so that it can be conveniently put on from the centre outward; after which it should be weighted or clamped in position for at least ten minutes while the cement hardens. Before a lube is replaced in a lyre a thorough inspection should he made to see that the original cause of the puncture has been removed, for frequently it happens that a deeply embedded nail or piece of metal which has not been noticed will soon puncture the repaired tube again.