## 5.4.8 – Parking Brakes 

Any time you park, use the parking brakes, except as noted below. Pull the parking brake control knob out to apply the parking brakes, push it in to release. The control will be a yellow, diamond- shaped knob labeled "parking brakes" on newer vehicles. On older vehicles, it may be a round blue knob or some other shape (including a lever that swings from side to side or up and down). 

Don't use the parking brakes if the brakes are very hot (from just having come down a steep grade), or if the brakes are very wet in freezing temperatures. If they are used while they are very hot, they can be damaged by the heat. If they are used in freezing temperatures when the brakes are very wet, they can freeze so the vehicle cannot move. Use wheel chocks on a level surface to hold the vehicle. Let hot brakes cool before using the parking brakes. If the brakes are wet, use the brakes lightly while driving in a low gear to heat and dry them. 

If your vehicle does not have automatic air tank drains, drain your air tanks at the end of each working day to remove moisture and oil. Otherwise, the brakes could fail. 

Never leave your vehicle unattended without applying the parking brakes or chocking the wheels. Your vehicle might roll away and cause injury and damage. 

1. Why should you be in the proper gear before starting down a hill? 

2. What factors can cause brakes to fade or fail? 

3. The use of brakes on a long, steep downgrade is only a supplement to the braking effect of the engine. True or False? 

4. If you are away from your vehicle only a short time, you do not need to use the parking brake. True or False? 

5. How often should you drain air tanks? 

6. How do you brake when you drive a tractor- trailer combination with ABS? 

7. You still have normal brake functions if your ABS is not working. True or False? 

These questions may be on your test. If you can’t answer them all, re-read subsection 5.4. 

## Subsection 5.4 Test Your Knowledge 

