Emergency Brake Adjustment Specs
The braking systems in modern automobiles are normally very reliable, and the emergency brake is seldom required for actual braking during e...
The braking systems in modern automobiles are normally very reliable, and the emergency brake is seldom required for actual braking during emergency situations any more. These days the emergency brake is used more as a parking brake or to prevent the vehicle from rolling when starting from a standing stop on an incline with a manual transmission. Regardless, the emergency brake should be kept properly adjusted at all times so that it will perform correctly when called upon.
Lever or Pedal Travel
Most manufacturers specify that the emergency brake should be fully engaged after six to nine clicks of the lever or pedal ratchet mechanism. This allows enough free travel in the pedal or lever so that the brake can fully disengage while maintaining enough remaining travel so that the lever or pedal can be moved further if needed. The travel is usually adjusted by turning a tensioning nut at the base of the lever or pedal mechanism.
Emergency Brake Holding Ability
Most manufacturers specify that the parking brake should be able to hold the vehicle without assistance on a slope of 15 to 30 degrees without the vehicle moving or creeping, regardless of whether the vehicle is facing forwards or backwards. It is also usually specified that the force used to apply the emergency brake cannot exceed 89.9 pounds for lever-operated brakes and 112.4 pounds for pedal-operated brakes when this test is being conducted. Note that most roads are designed such that slopes are less than 4 percent, and it is rare to see a road slope of greater than 8 percent even in hilly or mountainous terrain.
Lever or Pedal Sideways Movement
The side-to-side movement of the emergency brake lever or pedal must be small enough so that the ratchet mechanism that holds the lever or pedal in the engaged position cannot be disengaged by moving it sideways. This is normally tested by simply engaging the emergency brake and then moving the lever or pedal from side to side to see if the ratchet mechanism disengages.
Braking Function
Many manufacturers specify that the emergency brake should be able to stop the vehicle without assistance from a speed of up to 30 miles per hour within a specified distance. For example, an emergency brake should be able to stop a vehicle traveling at 20 miles per hour within a distance of 54 feet.
