Adjusting a park brake cable

Part 1. Preparation and safety

Objective

• Check and adjust park brake cable following the manufacturer's procedure.

Personal safety

Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

• Work clothing - such as coveralls and steel-capped footwear
• Eye protection - such as safety glasses and face masks
• Ear protection - such as earmuffs and earplugs
• Hand protection - such as rubber gloves and barrier cream
• Respiratory equipment - such as face masks and valved respirators

If you are not certain what is appropriate or required, ask your supervisor.

Safety check

• If the vehicle is being raised on a floor jack, safety stands must be used to prevent the possibility of the vehicle coming down while you are under it. Normally, the vehicle will be serviced on a hoist.
• Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.

Points to note

• The park brake must operate independently of the service brakes.
• Some manufacturers use an equalizer bracket to make sure that each brake station receives the same or equal pressure.
• The park brake can operate off the front or rear brakes. In some applications it operates off the back of the transmission output shaft.

Part 2: Step-by-step instruction

1. Prepare the vehicle
   There are two main ways of adjusting park brakes on vehicles; one method is done from underneath the vehicle, and the other from inside. A vehicle will only be fitted with one method of adjustment. The park brake is also known as the emergency brake. It must be able to operate independently from the service brakes. To check the brakes serviceability raise the car on a jack or hoist, making sure that the car is secure when raised. If you use a floor jack, make sure you support the vehicle with axle stands under the vehicle. Make sure the parking brake is off. Ensure the service brakes have been adjusted and are operative before carrying out any park brake adjustments. Check the shop manual for the correct adjustment travel for the vehicle.
2. Check/adjust parking brake cable (under vehicle)
   Trace the thin steel cables that run from each of the rear wheels until they meet under the car. Where they intersect there is normally a threaded rod with an adjusting nut located in a trunion. Loosen the jam nut, and turn the adjusting nut screw until the cables tighten, and then tighten the jam nut to hold the rod in place. Rotate the rear wheels to ensure they are not binding.
3. Check/adjust parking brake cable (in vehicle)
   Remove the protective cover from around the park brake lever or handle. Loosen the jam nut on the adjusting rod and turn the adjusting screw until the cables tighten, and then tighten the jam nut to hold the screw in place. Replace the cover over the cables to prevent any dirt entering into the vehicle. Rotate the rear wheels to ensure they are not binding.
4. Test the vehicle
   Lower the car, and then test it by parking on an incline, by applying the hand brake and counting the clicks to ensure that lever movement is in accordance with specifications and to make sure the brake holds the vehicle properly. While you’re driving note whether the parking light emergency light is on, if so look at the manufacturers recommendations for the correct method to adjust the parking brake sensor unit.