Shocks and struts play critical roles in your vehicle’s ability to deliver precise steering response, maximum stopping power and road-holding stability in a broad range of driving situations. Tires, brakes, and shocks or struts work together as a complete chassis system. If even one shock or strut is worn, the tires and brakes may not be able to deliver the margin of
safety you need in certain situations. This chassis system is known as the "Safety Triangle," representing the tires, brakes, and shocks/struts as well as the 3 key safety-related handling characteristics steering, stopping and stability. The primary role of shock absorbers and struts is to hold the tires against the road. This is particularly important when a vehicle hits a
bump or pothole because the impact causes the wheels to rebound away from the road surface. By absorbing the energy of these impacts, shocks and struts help minimize traction loss. A series of safety tests conducted with some popular US automobiles showed that vehicles equipped with 3 new shocks and one 50% degraded shock required an average of 4% more time and almost 6% greater distance to brake from 60 to zero miles per hour when compared with similar vehicles with new replacement shocks. (Testing was conducted on a dry, bumpy road surface.)
A popular SUV equipped with one degraded shock required nearly 10% more braking time (approximately 16 feet) than it did when equipped with new replacement shocks. In an accident-avoidance test, vehicles equipped with one degraded shock were forced to travel at a 4% lower speed, on average, to safely perform a sudden evasive maneuver when compared
to the same vehicles with new replacement shocks.
Vehicles capable of performing this test at higher speeds have a wider "safety envelope" and are less likely to spin, lose control or exit the roadway in situations when sudden evasive action is required. During catastrophic engine failure, broken pieces of valves, valve guides, valve seats, pistons, piston rings may wind up becoming lodged deep inside in the internal passages of the intake manifolds-which are very complex on modern engines. Absolute cleaning may be impossible, especially plastic intake manifolds. Reusing the manifold may result in debris later coming loose and being ingested into the replacement engine. If the engine suffered from such a failure (e.g. broken timing belt/chain, and the valves hit the pistons) with significant debris present, it
is best to replace the intake manifolds