Let the vehicle warm up before driving to ensure that fuel reaches the engine.

Wait to begin driving until the air compressor builds up a minimum pressure of 100 psi in both the primary and secondary systems.

Begin driving just after the vehicle starts.

Pump the pedal about 20 times to build pressure, then begin driving.

Prevent wheel lockup

Prevent the air compressor from overheating

Prevent the front brakes from being used on ice

Prevent the brakes from being used if downshifting would be more effective

On the rear

On the left side

On the front

On the top

Drains the water and compressor oil from the air tanks.

Prevents air from escaping if the air compressor has a leak.

Activates the emergency brakes when there is a leak.

Holds the spring brakes in position until they are used.

1 psi

2 psi

3 psi

4 psi

Reduce normal braking capacity.

Are equipped in addition to other braking systems and do not reduce normal braking power.

Are not effective on larger vehicles.

Are illegal in some states.

Once a week.

Every day.

Every hour.

Once a month.

Each system has separate air tanks, hoses, and lines.

The systems share air tanks, but each has its own separate hoses and lines.

Each system uses the same lines and hoses.

One system is the main braking system and a second system is ready to be used if the first one fails.

Push down the brake pedal.

Open the hood.

Release air from the air storage tanks.

Open the door to the cab.

Outside

Inside

Next to

On top of

Air brakes

Solid brakes

Liquid brakes

Gravity brakes

You will be unable to move the vehicle.

A separate air tank can be used to release the spring brakes for a short period of time.

You can use the spring brakes to continue driving normally.

The air tanks will automatically refill to a safe air pressure level.

3 psi in one minute.

6 psi in one minute.

8 psi in one minute.

4 psi in one minute.

There is a decreased risk of jackknifing.

There is an increased risk of jackknifing.

The brakes will not work as effectively as they would without ABS.

The brakes will become more sensitive.

25 psi

50 psi

75 psi

100 psi

Maintain full-capacity air pressure in the braking systems even when the vehicle is not running.

Maintain some air pressure in the braking systems when the vehicle is not running.

Must be run to build enough air pressure to brakes to operate properly.

Do not need time to build air pressure before a trip.

If they are too hot.

In colder weather.

If they are used.

If they get wet.

10 psi

25 psi

50 psi

100 psi

The service brake system

The parking brake system

The emergency brake system

The auxiliary brake system

Park on a hill and test the brakes.

Put on gloves and push in the slack adjusters.

Remove the drum and look inside.

Chock the wheels and disengage the parking brake.

Only required when transporting gases.

Only required when transporting liquids.

Used when transporting both liquids and gases.

Optional when transporting hazardous materials.

A service brake system

A parking brake system

An emergency brake system

An axle brake system

By tapping the brake pedal three times

By pushing in the brake control knob

By starting the vehicle

By tapping the accelerator twice

10 psi in a minute.

8 psi in a minute.

6 psi in a minute.

4 psi in a minute.

Prevent the front tires from skidding.

Prevent the front tires from overheating.

Create equal brake usage.

Remove uncertainty when applying the brakes.