The job of a shock absorber is just what it sounds like--to smooth out the normal shocks in daily driving. Shock absorbers dampen the effects of rough terrain, as well as the slight bouncing motion that occurs because of the springiness of the tyre.
Hydraulics and shock absorbers
If your shock absorber is leaking, it is probably leaking hydraulic fluid. Your shock absorber is probably made of a fluid-filled cylinder with a sliding piston inside of it. The piston absorbs energy through viscous friction, which occurs when the hydraulic fluid presses against it and slows down its motion. A leaky shock absorber is faulty because it has less hydraulic fluid, so it will provide less and less viscous friction as time goes on.
Consequences
Because shock absorbers make the drive smooth, many people think that faulty shock absorbers do not necessarily need to be replaced; after all, they don’t mind a few bumps as they drive. In actuality, driving with faulty absorbers can be extremely dangerous. Any bump can throw the car off balance, sending it out of control. Going over railroad trails, potholes or even speed bumps can easily cause a car accident. If a shock absorber is leaking, it is faulty and should be replaced immediately.
The shock absorbers (or dampers) in a car’s suspension system smooth out the recoil action of the springs as they absorb shocks transmitted by bumps in the road. One or more faulty shock absorbers will adversely affect a car’s handling
Most modern cars have telescopic shock absorbers, in which a piston operated by the movement of the car displaces oil at a controlled rate from one end of a cylinder to the other.
A telescopic shock absorber forming the main suspension leg and with a coil spring at the top, is called a MacPherson strut, and is used on many cars. Rear suspensions usually have a leaf or coil spring, with separate shock absorbers fitted between the axle or suspension arms and the bodywork.
Checking shock absorbers
Loosen the wheel nuts, jack up the car and support the chassis on axle stands so that the wheels hang free - never work under a car supported only by a jack. Remove the wheels.
Inspect each shock absorber for fluid leaks, which show as dark stains in the road grime that collects on its body and mounting points. Examine the body for deep dents, and the piston rod for signs of pitting or rusting. Any of theses faults call for a replacement unit.
The ends of the shock absorber are bolted through rubber bushes. Grip the upper and lower part of the unit and try to move it backwards and forwards; then twist it about its mounting bolt. If there is any movement replace the bushes.
The bounce test
Grip the bodywork above a wheel and bounce it vigorously a few times, then let go. The body should continue to bounce about twice more and then stop in its normal position. If it continues to bounce, the shock absorber at that point is weak.
Removing a shock absorber
With the car still on axle stands, place a jack under the suspension arm for a front shock absorber, or under the axle at the rear.
Locate the top mounting, which may be like the bottom one, or may be a threaded end of the piston called a pin mounting - it may protrude into the boot and you may have to remove some trim to get at it. For a pin mounting, count the number of threads above the nut; the same number must show when the shock absorber is replaced.Â
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written by sexy corsets, September 13, 2010
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written by swiss replica watches, December 11, 2011
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