Ohio CDL — Air Brakes Practice Test 2

1.The safety relief valve fitted to the first air tank is normally set to release pressure at what point?

125 psi100 psi55 psi150 psi

2.In a dual air brake system, if one of the two systems loses most of its pressure, what happens?

Both systems shut down and you have no brakes at allThe spring brakes instantly lock every wheelThe remaining system automatically doubles its pressureEither the front or rear brakes still work, but stopping takes longer

3.What does a supply pressure gauge tell the driver?

How much air pressure is in the tanksHow hard the brakes are being appliedWhether the spring brakes are setHow worn the brake linings are

4.With the foot brake fully applied and held for one minute on a combination vehicle, what pressure drop is considered too much?

More than 2 psiMore than 4 psiMore than 3 psiMore than 6 psi

5.If you find you must keep raising application pressure just to hold the same speed, what does that tell you?

The governor has cut out too earlyThe tanks were over-drained and need refillingThe ABS has taken over the brakingThe brakes are fading, so slow down and use a lower gear

6.In which situation should you NOT set the parking brakes, using wheel chocks instead?

Whenever the truck is fully loadedAny time you park on a downgradeWhen the brakes are very hot, or very wet in freezing temperaturesWhenever the engine is still running

7.What is the "controlled braking" method for an emergency stop?

Braking as firmly as possible short of locking the wheels, keeping steering inputs smallPressing the pedal all the way and releasing when the wheels lockPumping the pedal in a steady rhythm the whole stopUsing only the trailer brakes to slow down

8.How do you set the parking brakes with the diamond-shaped control knob?

Pull the knob out to apply them and push it in to releasePush the knob in to apply and pull it out to releaseTurn the knob a quarter turn clockwiseHold the knob down while pressing the brake pedal

9.Which type of foundation brake is the most common at each wheel?

The wedge brakeThe hydraulic caliper brakeThe s-cam drum brakeThe air-operated disc brake

10.Before checking the slack adjusters by hand, what should you do first?

Set the parking brakes and leave the engine runningDrain both air tanks completelyApply the foot brake and hold it downPark on level ground, chock the wheels, and release the parking brakes