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Show I BUCKING AUTO j CURE IS SHOWN Numerous Causes Contribute To Causes for Jerks In Car A complaint often heard from an-. H tomobile owners Is that their cart buck or Jerk at low speeds. This con-dition con-dition Is not only uncomfortable for the passengers, hut it Is detrimental to the car. The ordinary garage m- h:ntr usu.i 11 cannot m.ike a proper H diagnosis ami he puree the trouble only H after he has taken half the apart. H It your ear bucks md you de- termlne the cause after reading thia article, have a competent service man H the H A car in perfect mechanical oon- H dition throughout will throttle down H to five or four, or even three miles an H hour and pull evenly, but let there be H misf Irin'c and Immediately the whole car starts to jerk The misfiring so H reduces the power of the engin. H produce; such lapses In the power Im- I J pulses that the car must naturally run H with a Jerky motion. This applies to all cars, whether new or old. Whenever tbe engine cannot devel- op enough power to pull its load. It H falters Just as a horse would tighten and then permit slack In the traces h He'd pull In Jerks. You would do the sonic thing if you were dragging 1 a H A carbonized engine cannot develop H full power with a given throttle setting. Poor ignition, poor carburetor, Im-proper Im-proper valve timing or any abnormal engine conditio!) la llkelj to reduce H the power and make the engine falt- 1 Jt might H But apart from the engine there H are other causes of this common trou- fl ble. The commonest is due to too much play between the driving pin-Jon pin-Jon and the large bevel gear or ring re;ii in the axl- It may, however, H be due to excessive play anywhere H In the driving system, from the clutch B to the rear wheels Ii might even he Q caused by end-play the engine Hj When the engine under load ami F pulling, all the parts that move are H tight. This includes engine parte, H clutch, transmission, axle. etc. They H tighten like the traces tighten when a horse starts to pull and continues to H pull. So long as this pulling continue H there will he no noise, because the H parts are tight against each othe r they were not they could not pull h In a car that bucks. dup to excess- H ive play in the driving system, the same effect practically may be had by B slowing down and suddenly atlng. This may he done "by closing the throttle suddenly at twenty miles fl an hour and then suddenly opening it H At low speeds, however, it does not H'i require a greet amount of extra play H to cause a knock and the objetion- able bucking A clutch J worn plate and weak springs will fl against the flywheel ami give bucking effect. A worn clutch shaft or worn clutch bearing would H In the transmission the main shaft H must not move hack and forth. It does It will cause knock, though it H may not cause bucking due io the fact H that the irtovemcnt transmitted H to the 1 Universal joints with sliding 1 members of worn bushings on the H spiders will bucking. the H sliding shaft not H where In the Joint bo up H and not noticed, except as an occasion - B the have the JH the differential ami the wheels. The H axle shafts may not fit the H enough. The play here would he no- H tlced on starting the car and also on H throttling down This is to H since the play would hav4 to be tak- 1 c-n up before the shafts turn wheel ; i i , H shaft usually when the-. H splines become worn, the play H Ing may bucking, ft As mention"! before, PjYjvJvJvJvfll the driving pinion anil ring- gear is a PjVjvJvJvJvfl common cause of this Heat BjVjvJvJvJvM' in mind that through the emire PjVjvJvJvJvB ing system some play Is allowable it Ii jjBjVjVjB, Die excessive plav that causes the jfjfjfjfjfjfj H of wire It ofter H happens that (he wheel-driving mem B hers become worn, giving the ef feet as though there were play in th B differential. If a no BBBH tight in place It will ship -jdew.it s f and this knot krng often i mlstnki foi BJl a bucking rear |