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What's the 3 types of braking systems?
- 1. Mechanically- Actuated Brakes
- 2. Hydraulic- Actuated Brakes
- 3. Air- Actuated Brakes
What is mechanically brakes used on?
Most passenger vehicles, as a parking brake. Can be used to slow or stop vehicle if hydraulic brakes fail.
What is hydraulic brakes used on?
Most passenger and lighter duty vehicles. Uses hydraulic fluid to actuate brakes.
What is air brakes used on?
Large vehicles such as fire apparatuses which require larger brake component's.
What are the drawbacks on air-actuated brakes?
Does not react quickly.
Requires removal of water and oil from air system. Water drains should be emptied daily.
What are the 3 subsystems of the air-actuated braking systems.
1. Primary ( service brakes)
2. Secondary (Emergency/Parking brakes)
3. Emergency Brake Release
When does the Emergency/Parking brake automatically activate?
When air drops below 40-psi
7 step brake check. (1-4)
level ground, wheels chocked, parking brake released, air gauge reads 120 psi, engine off
- 1. Air pressure loss rate
- static- no more than 2 psi in one minute
- applied- 3 psi in one minute
- 2. Low air pressure warning device
- Activaton- fan brakes to ensure the low air warning activates before pressure drops below 60psi
- 3. Emergency brake Activates around 20-40 psi, ensure it won't release
- 4. Compressor buildup rate Low air should stop as pressure rises over 60.
- Primary should fill first then hold at 80 psi. Then rise together.
- When both gauges rise check to see they rise form 85-100 in 45 seconds or less.
7 step brake check. (5-7)
- 5. Governor Cut In/Out
- Cut out- should turn compressor off at 120-125 psi.
- Cut in- Release parking brake and fan service brakes. No rise between 110-120, until dropped below 100 psi.
- 6. Parking Brake
- Parking brake released, trans in lowest gear, attain 5 mph, apply parking brake, brake should stop truck.
- 7. Service Brake
- Parking brake released, trans in lowest gear, attain 5 mph, apply service brakes, hands on wheel.
- No unusual feel when brakes applied. steering when should not pull to one side.
What are the steps to check hydraulic brakes?(pickups, sedans, state trucks)
- 1. Make visual of underside for any fluid leakage.
- 2. Check pedals for spongy unusual feel
- 3. Pump pedal 3 times and hold for 5 seconds to check pedal to ensure it does not "bottom"
- 4. Check brake fluid once a month
- 5. Check for free play 1/4" - 1/2" from top
What are the steps for the mechanical brakes?
- 1. Engage and disengage hand or foot brake for engagement and release
- 2. Try to move forward with brake engaged, should hold vehicle.
HFD auxiliary vehicles shall be equipped with what?
- 1- DOT approved bi-directional reflective triangle kit containing 3 triangles
- 1- fully charged multi purpose fire ext. 2A-10BC.
- 1- 24-piece first aid kit.
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