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ktaylor1
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What's the 3 types of braking systems?
- 1. Mechanically- Actuated Brakes
- 2. Hydraulic- Actuated Brakes
- 3. Air- Actuated Brakes
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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.
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What is hydraulic brakes used on?
Most passenger and lighter duty vehicles. Uses hydraulic fluid to actuate brakes.
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What is air brakes used on?
Large vehicles such as fire apparatuses which require larger brake component's.
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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.
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What are the 3 subsystems of the air-actuated braking systems.
1. Primary ( service brakes)
2. Secondary (Emergency/Parking brakes)
3. Emergency Brake Release
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When does the Emergency/Parking brake automatically activate?
When air drops below 40-psi
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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.
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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.
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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
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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.
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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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