Pennsylvania CDL — Air Brakes Practice Test 6

11.Other air brake vehicles such as trucks, buses, trailers and converter dollies must have ABS if built on or after which date?

March 1, 1997March 1, 1998March 1, 1994March 1, 1975

12.If the ABS warning lamp shows the system has failed, what is true about your brakes?

You have lost all braking abilityOnly the parking brake still worksYour regular brakes still work; get the ABS repaired soonThe spring brakes will apply on their own

13.What is the job of the air compressor governor?

It caps the maximum road speed the vehicle can reachIt regulates the points at which the compressor starts and stops adding air to the tanksIt drains water out of the storage reservoirs on its ownIt alerts the driver whenever tank pressure gets dangerously low

14.In the snubbing technique, once you have braked to about 5 mph below your safe speed, what do you do next?

Hold steady brake pressure for the rest of the gradeShift into a higher gear and coastSet the parking brake to hold the lower speedLet off the brakes, then reapply once you return to your safe speed

15.If a vehicle has an alcohol evaporator, is daily draining of the air tanks still needed?

No, the evaporator removes all the moisture on its ownOnly when the weather is below freezingYes, unless the tanks have automatic drain valvesOnly when the compressor carries its own separate oil supply

16.What is true about front-wheel braking on a commercial vehicle?

Front brakes should be disabled on wet roadsFront-wheel braking helps in all conditions and rarely causes skids, even on iceFront brakes are only useful on dry pavementFront-wheel braking sharply raises the chance of a skid

17.Total stopping distance for an air brake vehicle is made up of which four parts?

Perception, reaction, gear-selection and braking distancesReaction, brake lag, coasting and skid distancesPerception, brake lag, downgrade and braking distancesThe perception and reaction distances, plus the brake-lag and braking distances

18.Where is the ABS malfunction lamp located on a trailer?

On the rear bumper at the centerOn the instrument panel inside the cabOn the left side, at a front or rear cornerBehind the tractor's grille

19.A tank fitted with a manually operated drain valve should be emptied how often?

Once a weekOnly during scheduled maintenanceAt the close of every day you driveOnce every 1,000 miles

20.If the safety valve lets air escape, what does that tell you?

The system is fine and no action is neededTank pressure is simply at its normal levelThere is a fault that a mechanic should repairThe alcohol evaporator needs refilling