CDL Hazmat Vehicle Inspection and Safety

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

How often should dual tires be inspected while transporting hazardous materials?

3 hours or 150 miles

2 hours or 100 miles (correct)

4 hours or 200 miles

1 hour or 50 miles

Which sensor is used to assess engine temperature?

Air Temperature sensor

Throttle position sensor

Coolant sensor (correct)

Manifold absolute pressure sensor

What is the most effective and secure technique for descending a steep slope?

Changing to a lower gear (correct)

Changing to neutral and coasting down hill

Changing to a higher gear

Remaining in the same gear

What is the electrolyte of a battery a combination of?

Water and Sulfuric acid Signup and view all the answers

How would delayed valve timing due to a stretched timing belt affect a single overhead camshaft engine?

Low RPM power will be reduced Signup and view all the answers

How should the integrity of an electrical connection be tested?

For tightness, then a voltage drop should be performed across the connector Signup and view all the answers

When measuring an unknown voltage or current, what range selection should be set?

The point midway between the lowest and the highest range Signup and view all the answers

Which spring suspension system is used above the main leaf spring assembly and only under severe loads?

Auxiliary spring suspension Signup and view all the answers

What is the correct procedure when changing the coil assembly in a Supplemental Inflatable Restraint steering column?

Lock the steering column, and disable the airbag Signup and view all the answers

Which tool is used to measure coolant freeze protection?

Hydrometer Signup and view all the answers

What does a specific gravity of 1.225 at 80°F indicate about a battery's state of charge?

The battery is approximately 75% charged Signup and view all the answers

Can a hydrometer be used to check battery state of charge on a maintenance-free battery?

No, it is not possible Signup and view all the answers

What is the purpose of an auxiliary spring suspension?

To provide additional support under heavy loads Signup and view all the answers

What is the most likely cause of a tire vibrating at 40 to 60 kilometres per hour?

Weak shock absorbers Signup and view all the answers

What would happen to the reading on a pressure gauge if a gas is cooled?

It would decrease Signup and view all the answers

When towing multiple trailers, which trailer should be closest to the tractor?

Heaviest trailer Signup and view all the answers

What is the most likely cause of a compressor clutch that will not engage despite having good power and ground at the clutch coil?

Incorrect air gap Signup and view all the answers

What test should be performed if the charging system's output is below the rated output?

Alternator output (full-field test) Signup and view all the answers

How many seconds of gap should be maintained while driving a 100-foot tandem trailer combo at 50 miles per hour on a dry road with adequate visibility?

11 Signup and view all the answers

What is the most likely cause of blue exhaust smoke?

Worn valve guides Signup and view all the answers

How is a shuddering situation repaired during torque converter lock up?

By replacing the torque converter Signup and view all the answers

What is evaluated during a road test to certify that a diesel engine has low power?

Boost and fuel pressures Signup and view all the answers

What would result in a low amperage draw and a sluggish cranking speed?

High starter cable resistance Signup and view all the answers

What is likely to cause the failure of the conveyer bearings on a paver?

Lack of grease Signup and view all the answers

What is the most likely cause of an engine noise that sounds like a knock at the side of the engine, louder when cold and reduced when the engine reaches operating temperature?

Piston slap Signup and view all the answers

What is the protocol for evaluating or fixing seat belt systems after a collision?

Inspect belt and buckle operation, then inspect the stitching at the energy management loops Signup and view all the answers

What is the likely cause of white smoke emitting from the exhaust when the engine is under stress?

Coolant loss Signup and view all the answers

What power is required to keep 250 pounds of block and tackle with five rope falls and little friction?

50 lbs Signup and view all the answers

Why is it necessary to remove the ring ridge before removing the piston/rod assembly?

To prevent damage to the piston ring lands Signup and view all the answers

What is the correct procedure when changing a clutch?

Check bell housing alignment before installing clutch assembly Signup and view all the answers

What is the likely cause if a warning bulb does not illuminate, but does when the cable connecting the lamp to the transmitting device is grounded?

Sending unit is defective Signup and view all the answers

What is the most likely cause if the starting armature spins, but the engine does not start?

Starter drive overrunning clutch slippage Signup and view all the answers

At what pressure does a warning provide before air pressure in the air tank falls?

60psi Signup and view all the answers

What is the primary purpose of idling the engine prior to shutting it off?

Cool the engine oil Signup and view all the answers

What is the benefit of checking bell housing alignment before installing a new clutch?

To prevent damage to the clutch assembly Signup and view all the answers

What is evaluated during a road test to certify that a diesel engine has low power?

Fuel temperature and exhaust back pressure Signup and view all the answers

What would result in a low amperage draw and a sluggish cranking speed?

High starter cable resistance Signup and view all the answers

What is likely to cause the failure of the conveyer bearings on a paver?

Lack of grease Signup and view all the answers

What is the most likely cause of an engine noise that sounds like a knock at the side of the engine, louder when cold and reduced when the engine reaches operating temperature?

Piston slap Signup and view all the answers

What is the protocol for evaluating or fixing seat belt systems after a collision?

Inspect belt and buckle operation, then inspect the stitching at the energy management loops Signup and view all the answers

What is the likely cause of white smoke emitting from the exhaust when the engine is under stress?

Coolant loss Signup and view all the answers

Why is it important to check the refrigerant oil level?

To ensure proper lubrication Signup and view all the answers

What is the suggested cause if vacuum falls to 8 inches Hg and then recovers to 18 inches Hg during a snap throttle test?

Restricted exhaust system Signup and view all the answers

What is correct when fixing automatic transmissions?

Clutch packs may be pressure tested using low pressure air. Signup and view all the answers

What must be done prior to disassembling a parking brake with a spring?

cage the spring Signup and view all the answers

What is likely to cause a vehicle equipped with a short arm long arm suspension to wander?

Both a and b Signup and view all the answers

What must be connected before backing beneath a tractor-trailer?

The air brake system Signup and view all the answers

What is the suggested cause if vacuum falls to 8 inches Hg and then recovers to 18 inches Hg during a snap throttle test?

Restricted exhaust system Signup and view all the answers

What is the most likely cause of a bent connecting rod?

Hydrostatic lock Signup and view all the answers

Which operating circumstance would cause the housing of a gear pump to break or the pump shaft to detach?

Over pressure operation Signup and view all the answers

How can you perform an emergency stop using the stab braking technique with air brakes?

d) Brake as hard as you can, get off the brakes when the wheels lock, get back on the brakes when the wheels start rolling again Signup and view all the answers

What is the purpose of twin parking control valves if your vehicle is equipped with them?

To stay parked without using up service air pressure Signup and view all the answers

How should you check the slack adjuster?

Park on level ground, turn off parking brakes, pull hard on each slack adjuster Signup and view all the answers

What is the most likely cause of a gear pump failure?

Operation with a high pump inlet restriction Signup and view all the answers

How can you prevent a gear pump from breaking or the pump shaft from detaching?

Ensure the pump inlet restriction is within acceptable limits Signup and view all the answers

What is the correct procedure for checking the parking brake system?

Park on level ground, turn off parking brakes, pull hard on each slack adjuster Signup and view all the answers

What action should be taken to prevent deployment of the air bag?

Disconnect the multi-function switch Signup and view all the answers

What should be done if the yellow check engine light is illuminated?

Test all circuits related to the fault Signup and view all the answers

What will happen if the spark plug wires are not installed in the correct order?

Engine will misfire upon starting Signup and view all the answers

What is the abbreviation for RAM?

Random access memory Signup and view all the answers

In an acetylene cylinder, what is acetylene stabilised by?

Acetone Signup and view all the answers

What is the basis for closed loop functioning in a fuel injection system?

Oxygen content of exhaust gases Signup and view all the answers

What is the correct cost of fuel needed to travel 620km to the nearest dollar?

$106 Signup and view all the answers

What is a huge single panel, frame, or assemblage of panels on which switches, over current and other protection devices, buses, and often instruments are placed?

Control panel Signup and view all the answers

Which component must be driven by a battery box to increase pressure?

Servo valve Signup and view all the answers

What is the correct procedure when replacing seat anchor bolts?

Remove thread sealer from threads and install new bolts with an impact wrench Signup and view all the answers

Which component links to the engine's exhaust manifold to be activated?

Turbocharger Signup and view all the answers

What is the concluding step when installing a torque converter on a transmission?

Torque the drive/flex plate retaining bolts Signup and view all the answers

What customer concern could be caused by a defective ECT return spring malfunction?

Rough idle Signup and view all the answers

What type of truck spring suspension system is installed above the primary leaf spring assembly?

Air spring suspension Signup and view all the answers

What is the purpose of the Temposonic transducer?

To increase pressure drive the servo valve Signup and view all the answers

What is the correct procedure when testing the Electronic Controlled Throttle circuit?

Use a lap-top computer and manufacturer software Signup and view all the answers

What is evaluated during a road test to certify that a diesel engine has low power?

Fuel temperature and exhaust back pressure Signup and view all the answers

What would result in a low amperage draw and a sluggish cranking speed?

Overcharged battery Signup and view all the answers

What is likely to cause the failure of the conveyer bearings on a paver?

Lack of tension Signup and view all the answers

What is the most likely cause of an engine noise that sounds like a knock at the side of the engine, louder when cold and reduced when the engine reaches operating temperature?

Piston slap Signup and view all the answers

What is the protocol for evaluating or fixing seat belt systems after a collision?

Inspect belt and buckle operation, then inspect the stitching at the energy management loops Signup and view all the answers

What is the likely cause of white smoke emitting from the exhaust when the engine is under stress?

Coolant leak Signup and view all the answers

Why is it important to check the refrigerant oil level?

To ensure proper lubrication Signup and view all the answers

What would cause a coolant loss?

Recently, coolant was supplied to a heated engine Signup and view all the answers

What is the correct sequence of oil circulation in an engine?

sump to oil pump to bearings to filter Signup and view all the answers

What is the correct procedure when inflating a wheel and tire assembly?

Cage or confine the wheel and tire assembly and use a remote fill / deflate device Signup and view all the answers

Before opening a connection in the sensor harness of an electronic control system, what must be done?

Ensure the key switch is turned off Signup and view all the answers

What would cause a HEUI fuel system to be difficult or impossible to start?

Leaking injector oil return Signup and view all the answers

What would cause a hydrostatic drive system to function in backward but not forward?

Servo pistons are scored Signup and view all the answers

What is the first step to take when a linear positioner circuit malfunctions?

Consult the repair manual Signup and view all the answers

What measures must be followed when inflating a wheel and tire assembly comprised of many components?

Cage or confine the wheel and tire assembly and use a remote fill / deflate device Signup and view all the answers

What would cause a hydrostatic drive system to function in reverse but not forward?

Servo pistons are scored Signup and view all the answers

What should be done if the lubricant level in the differential, steering reservoir, or gearbox is very low?

Fill to proper level with specified lubricant. Signup and view all the answers

What is the correct approach for measuring main bearing clearance using plastigaged?

Install plastigage, lubricate journal, torque bearing cap, read clearance. Signup and view all the answers

Which of the following is the ratio of the primary winding to the secondary of an electric transformer that has 240 turns, and the secondary winding has 15 turns?

240/15 Signup and view all the answers

Which of the following is the maximum allowable temperature for a sealed bearing?

180ºF Signup and view all the answers

Which object should never be transported with passengers on a bus?

Tear gas Signup and view all the answers

Which technician is correct?

Technician 2 Signup and view all the answers

What should be done if the lubricant level in the differential, steering reservoir, or gearbox is very low and cannot be corrected?

Recommend the owner return it later for service. Signup and view all the answers

What is the primary concern when transporting certain objects?

Safety of the passengers Signup and view all the answers

If all warning gauges in the instrument cluster read high, what is the likely cause?

A shorted ground Signup and view all the answers

What should be installed next when rebuilding a dual countershaft transmission?

The high/low range synchronizer Signup and view all the answers

What is the correct adjustment sequence for a power steering box?

Adjust poppets, sector shaft endplay, and input shaft preload Signup and view all the answers

What is the typical voltage range of a quality oxygen sensor?

0.450 volts to 1.000 volts Signup and view all the answers

What is the configuration of a 12-volt car battery?

Six cells connected in series Signup and view all the answers

During an air conditioning performance test, what does a hot compressor outlet indicate?

This is a normal condition Signup and view all the answers

What is the effect of a shorted ground on the instrument cluster?

All warning gauges read high Signup and view all the answers

What is the significance of low resistance in a balancing coil gauge?

The sending unit has low resistance Signup and view all the answers

What should be done to prevent deployment of the air bag?

Disconnect the multi-function switch Signup and view all the answers

What will occur if the spark plug wires are not installed in the correct order?

Engine will misfire upon starting Signup and view all the answers

What is the abbreviation for RAM?

Random access memory Signup and view all the answers

In an acetylene cylinder, acetylene is stabilised by which of the following?

Ferond acetone water Signup and view all the answers

What is the basis for closed loop functioning in a fuel injection system?

All of the above Signup and view all the answers

What will be the cost of fuel needed to travel 620km to the nearest dollar?

$106 Signup and view all the answers

What is a huge single panel, frame, or assemblage of panels on which switches, over current and other protection devices, buses, and often instruments are placed on the face, back, or both?

Panelboard Signup and view all the answers

If the yellow check engine light is illuminated, what should be done?

Test all circuits related to the fault Signup and view all the answers

What would happen to the power of a single overhead camshaft engine if the valve timing is delayed due to a stretched timing belt?

High RPM power will be reduced Signup and view all the answers

How should an electrical connection be tested for integrity?

For tightness, then a voltage drop should be performed Signup and view all the answers

What is the composition of a battery's electrolyte?

Sulfuric acid and water Signup and view all the answers

What is the best technique for descending a steep slope?

Changing to a lower gear Signup and view all the answers

What would happen if the refrigerant oil level is not checked regularly?

The system will experience reduced performance Signup and view all the answers

What is the primary concern when transporting hazardous materials?

Public safety Signup and view all the answers

What is the purpose of a coolant sensor in a vehicle?

To monitor engine temperature Signup and view all the answers

What is the most likely cause of a tire vibrating at 40 to 60 kilometres per hour?

Unbalanced tires Signup and view all the answers

What is the consequence of a tractor protection valve closing when the trailer breaks away from a combination vehicle?

The trailer brakes will activate and the air lines will separate. Signup and view all the answers

What is the correct procedure to check the continuity of wires that carry digital signals?

Use a logic probe. Signup and view all the answers

What type of fuel systems are used for engines with spark ignition?

Carburetor and fuel injection. Signup and view all the answers

What is the primary source of power for most electrical gauges?

Battery regulated voltage. Signup and view all the answers

What is the first step in removing refrigerant from an air conditioning system?

Identify the type of refrigerant. Signup and view all the answers

How much torque is transmitted to the driving pinion of the front axle of a four-wheel-drive car in low range?

162 pounds. Signup and view all the answers

What is the most fuel-efficient braking method?

Engine braking. Signup and view all the answers

What should be checked before backing behind a trailer?

All of the above. Signup and view all the answers

What should you do when driving a double trailer and need to prevent a collision?

Use controlled or stab braking Signup and view all the answers

What is a common lubricant for cylinder head bolts?

No seize compound Signup and view all the answers

What is a benefit of endurance braking systems?

Reduced brake wear on long hills Signup and view all the answers

What is a likely cause if a fuel gauge reads full?

Wire to sending unit grounded Signup and view all the answers

What can cause a hydrostatic axial piston drive motor to fail?

Restricted inlet line or filters Signup and view all the answers

What is a method to reduce fuel consumption?

Using lower gears Signup and view all the answers

What are slack adjusters?

An adjusting nut on the backside of the brake drum Signup and view all the answers

What can produce vibration in the driveline?

All of the above Signup and view all the answers

During a road test, what is evaluated to certify that a diesel engine has low power?

Fuel temperature and exhaust back pressure Signup and view all the answers

What would result in a low amperage draw and a sluggish cranking speed?

High starter cable resistance Signup and view all the answers

What is likely to cause the failure of the conveyer bearings on a paver?

Lack of tension Signup and view all the answers

What is the most likely cause of an engine noise that sounds like a knock at the side of the engine?

Piston slap Signup and view all the answers

What is the protocol for evaluating or fixing seat belt systems after a collision?

Inspect belt and buckle operation, then inspect the stitching at the energy management loops Signup and view all the answers

What is the likely cause of white smoke emitting from the exhaust when the engine is under stress?

Coolant loss Signup and view all the answers

What would cause a coolant loss?

Coolant leak Signup and view all the answers

Why is it important to check the refrigerant oil level?

To ensure proper lubrication of the compressor Signup and view all the answers

What determines the PO135 code's value?

A short at the power feed terminal at the oxygen sensor heater circuit. Signup and view all the answers

What causes faded or failing brakes?

Over heating, low air pressure, and not relying on the engine braking effect. Signup and view all the answers

What is the right procedure for adjusting excessive valve stem height?

Grinding material from valve tip. Signup and view all the answers

What causes a primary pump failure in a hydrostatic system shortly after installation?

Contamination. Signup and view all the answers

What is the likely cause of an indicator lamp malfunction?

A faulty oxygen sensor. Signup and view all the answers

What is the correct diagnosis for a PO135 code?

Oxygen sensor heater circuit problem, bank 1, sensor 1. Signup and view all the answers

What is the likely cause of a car's drivability not being affected by an indicator lamp malfunction?

The car's engine is not affected by the malfunction. Signup and view all the answers

What is the relation between the indicator lamp malfunction and the PO135 code?

The indicator lamp malfunction is a symptom of the PO135 code. Signup and view all the answers

Which type of sensor delivers positional information?

Potentiometer Signup and view all the answers

Which component is commonly found in a battery?

Sulphuric acid Signup and view all the answers

What type of wire rope is flexible and suitable for overhead cranes?

6-37 Signup and view all the answers

What happens when you constantly use the brakes on a lengthy descent?

Brake fade Signup and view all the answers

In an engine with reverse cooling, where does the coolant flow from?

Engine block into the radiator outlet Signup and view all the answers

How many crankshafts are found in a V-type engine?

2 Signup and view all the answers

What should be examined before replacing a control module?

All module powers and grounds Signup and view all the answers

What happens to the majority of unused energy in a hydraulic system?

It is converted into heat Signup and view all the answers

What is the torque transmitted to the driving pinion of the front axle of a four-wheel-drive car in low range (ratio of 1.8:1)?

162 pounds Signup and view all the answers

Which of the following braking methods consumes the least amount of fuel?

engine brake Signup and view all the answers

Before backing behind a trailer, you must ensure that:

Tractor protection valve is normal Signup and view all the answers

What tool can be used to check the continuity of wires that carry digital signals?

logic probe Signup and view all the answers

What are the two types of fuel systems for engines with spark ignition?

carburetor and fuel injection Signup and view all the answers

What do the majority of electrical gauges rely on?

battery regulated voltage Signup and view all the answers

What is the first stage in removing refrigerant from an air conditioning system?

Identify the type of refrigerant Signup and view all the answers

What happens when the trailer breaks away from a combination vehicle, separating both air lines?

Tractor protection valve closes and tractor loses all air pressure Signup and view all the answers

During a cooling system pressure test, the pressure decreases gradually, but there are no visible exterior leaks. What is the difficulty?

Transmission cooler is leaking coolant into the transmission. Signup and view all the answers

How can you tell if your brakes are deteriorating?

You have to push harder on the brake pedal to control your speed on a downgrade. Signup and view all the answers

Which of the following may be used to test the functioning of brake warning systems and low air warnings?

turning on the ignition Signup and view all the answers

Which of the following conditions is the most likely to cause a vehicle to overheat?

clogged radiator Signup and view all the answers

How should an oversize piston of 0.020 be installed?

Bore the cylinder to 0.022 in (0.56 mm) to provide clearance, then hone to a suitable finish. Signup and view all the answers

What is the most likely cause of a brake pedal that feels spongy when pressure is applied?

Air in the brake system Signup and view all the answers

What should you do if the pressure on the brake pedal is released and speed increases?

Check the brake system for air leaks Signup and view all the answers

What is the most likely cause of a transmission cooler that is leaking coolant into the transmission?

Leaking transmission seals Signup and view all the answers

What determines the code PO135's value?

A short at the power feed terminal at the oxygen sensor heater circuit Signup and view all the answers

What causes faded or failing brakes?

Over heating, low air pressure, and not relying on the engine braking effect Signup and view all the answers

What is the right procedure for adjusting excessive valve stem height?

Grinding material from valve tip Signup and view all the answers

Shortly after installation, if the primary pump of a hydrostatic system breaks, the failure was caused by which of the following?

Contamination Signup and view all the answers

What is the likely cause of an Indicator Lamp Malfunction complaint?

A short at the power feed terminal at the oxygen sensor heater circuit Signup and view all the answers

What is the likely cause of a code PO135?

A short at the power feed terminal at the oxygen sensor heater circuit Signup and view all the answers

What is the correct procedure for fixing a car with an Indicator Lamp Malfunction complaint?

Fixing the oxygen sensor heater circuit issue Signup and view all the answers

What is the likely cause of a car's drivability not being affected by an Indicator Lamp Malfunction complaint?

The issue is not severe enough to affect drivability Signup and view all the answers

What determines the frequency of an alternating current signal?

number of cycles per unit of time Signup and view all the answers

Which statement about automatic transmission maintenance is true?

Clutch pack clearances must be measured before replacement Signup and view all the answers

Why does the camshaft position sensor provide information to the PCM (Engine Computer)?

determine the crankshaft position information for injector and spark timing Signup and view all the answers

How is a decrease in front gear accomplished from a basic planetary gear set?

Carrier assembly must be the input member Signup and view all the answers

The magnetic field inside an alternator is produced by?

Rotor armature Signup and view all the answers

How do you do a service check on the coolant?

Coolant should be checked for concentration using a hydrometer Signup and view all the answers

What should be done before replacement in automatic transmission maintenance?

Clutch pack clearances must be measured Signup and view all the answers

What is the purpose of the camshaft position sensor?

to determine crankshaft position for injector and spark timing Signup and view all the answers

Study Notes

Hazardous Materials Transportation

Dual tires should be inspected every 1 hour or 50 miles while transporting hazardous materials.

Engine Temperature

The Coolant sensor is used to assess engine temperature.

Descending Steep Slopes

The most effective and secure technique for descending a steep slope is to change to a lower gear.

Battery Composition

The electrolyte of a battery is a combination of water and sulfuric acid.

Valve Timing

If the valve timing is delayed due to a stretched timing belt in a single overhead camshaft engine, high RPM power will be reduced.

Electrical Connection

The integrity of an electrical connection should be tested by checking for tightness, then performing a voltage drop test across the connector.

Measuring Unknown Voltage

When measuring an unknown voltage or current, set the range selection to a point midway between the lowest and the highest range, and work upward and downward until the proper range is determined.

Suspension Systems

The auxiliary spring suspension system is positioned above the main leaf spring assembly and is only used under severe loads.

Supplemental Inflatable Restraints

When changing the coil assembly in the steering column of a Supplemental Inflatable Restraint, lock the steering column, and disable the airbag.

Coolant Freeze Protection

A hydrometer is used to measure the proper coolant freeze protection.

Battery State of Charge

A specific gravity of 1.225 at 80°F indicates that a battery's state of charge is approximately 75%.

Suspension Testing

If a tire vibrates at 40 to 60 kilometers per hour, the suspension is tested by bouncing the vehicle five or six times before coming to rest, indicating a weak or broken spring.

Gas Container Pressure

The pressure gauge on a container carrying a gas would indicate a lower reading if the gas is cooled.

Towing Multiple Trailers

The heaviest trailer should follow the tractor while towing several trailers.

Compressor Clutch Engagement

If a compressor clutch will not engage and the power and ground at the clutch coil are good, the most likely cause is an incorrect air gap.

Charging System Output

If the charging system's output is below the rated output, the test that should be performed is an alternator output (full-field test).

Trailer Towing Distance

When driving a 100-foot tandem trailer combo at 50 miles per hour on a dry road with adequate visibility, a 13-second gap should be maintained.

Exhaust Smoke

Blue exhaust smoke is likely caused by a leaking injector cup.

Torque Converter Lockup

A shuddering situation during torque converter lockup is repaired by checking the refrigerant oil level.

Diesel Engine Power

During a road test, fuel temperature and exhaust back pressure are evaluated to certify that a diesel engine has low power.

Starter Motor Issues

A low amperage draw and sluggish cranking speed are likely caused by high starter cable resistance.

Paver Conveyer Bearings

Failure of the conveyer bearings on a paver is often caused by a lack of lubricant on the chains.

Engine Noise

An engine noise that sounds like a knock at the side of the engine that is louder when the engine is cold and goes away or is reduced when the engine reaches operating temperature is likely caused by piston slap.

Seat Belt Systems

After a collision, the protocol for evaluating or fixing seat belt systems is to inspect belt and buckle operation, then inspect the stitching at the energy management loops.

Engine Coolant Loss

If coolant was recently supplied to a heated engine and the exhaust emits white smoke, there is a coolant loss.

Block and Tackle

250 pounds of block and tackle with five rope falls and little friction require 125 pounds of power to keep.

Piston and Ring Assembly

Removing the ring ridge before removing the piston/rod assembly is done to prevent damage to the piston ring lands.

Clutch Replacement

When changing a clutch, the transmission should be installed, then the bore alignment should be checked.

Warning Lamp Diagnosis

If a warning bulb does not illuminate, but does when the cable connecting the lamp to the transmitting device is grounded, it suggests that the sending unit is defective.

Starter Motor Issues

If the starting armature spins, but the engine does not start, the most likely cause is that the engine is seized.

Air Tank Pressure

A warning is provided before air pressure in the air tank falls below 60psi.

Engine Idling

The primary purpose of idling the engine prior to shutting it off is to give the engine oil time to properly lubricate the turbo-compressor.

Snap Throttle Test

During a snap throttle test, vacuum falls to 8 inches Hg (27 kPa) and then recovers to 18 inches Hg (61 kPa), suggesting a restricted exhaust system.

Alternator Troubleshooting

A faulty field circuit may cause an alternator to have zero output, as suggested by Technician 1.
A blown fusible link from the battery to the alternator could also be the cause, as suggested by Technician 2.

Automatic Transmission Repair

Clutch packs can be pressure tested using low pressure air, not high pressure air.
Metal contaminated coolers can be flushed and re-used, but not torque converters.

Parking Brake Maintenance

Before disassembling a parking brake with a spring, the spring should be caged.

Suspension and Steering

A worn relay rod ball socket can cause a vehicle to wander, as suggested by Technician 1.
The adjustment limit for the tie rod may be out of spec, as suggested by Technician 2.

Tractor-Trailer Safety

Before backing beneath a tractor-trailer, the electrical service cable must be connected.

Diesel Engine Diagnosis

During a road test, fuel temperature and exhaust back pressure are evaluated to certify that a diesel engine has low power.

Starter Motor Troubleshooting

A high mechanical resistance or shorted armature can cause a low amperage draw and sluggish cranking speed.

Paver Maintenance

Lack of lubricant on the chains of a paver can lead to the failure of the conveyor bearings.

Engine Noise Diagnosis

A knocking sound that is louder when the engine is cold and goes away or is reduced when the engine reaches operating temperature suggests a piston slap.

Seat Belt Systems

After a collision, seat belt systems should be evaluated by inspecting belt and buckle operation, then inspecting the stitching at the energy management loops.

Coolant Leaks

White smoke from the exhaust suggests a coolant loss, possibly due to a recent coolant supply to a heated engine.

Gear Pump Operation

Operation with a high pump inlet restriction can cause the housing of a gear pump to break or the pump shaft to detach.

Brake Adjustment

The slack adjuster should be checked by parking on level ground, turning off the parking brake, and pressing the brake pedal.

Connecting Rod Damage

A bent connecting rod can be caused by leaking liner O-rings, hydrostatic lock, piston to valve contact, or excessive bearing clearance.

Air Brake System

Twin parking control valves can be used to balance the service brake system or apply more brake pressure if the main tank is getting low.

Emergency Stopping

The stab braking technique with air brakes involves pressing hard on the brake pedal and applying full hand valve until stopped.

Seat Anchor Bolt Replacement

When replacing seat anchor bolts, the thread sealer should be removed from the threads, and new bolts should be installed with an impact wrench.

Turbocharger Operation

The turbocharger of a diesel engine is linked to the engine's exhaust manifold to be activated.

Torque Converter Installation

When installing a torque converter on a transmission, the converter run-out should be checked.

Electronic Throttle Control

A defective ECT return spring malfunction can cause a rough idle, low power, detonation, or high idle.

Suspension Systems

An air spring suspension system can be installed above the primary leaf spring assembly and would only be used while carrying big loads.

Air Bag Systems

When working with air bag systems, the multi-function switch should be disconnected to prevent deployment.

Electronic Control Modules

When diagnosing a stored DTC P1121 Electric Throttle Control Actuator, the Electronic Controlled Throttle circuit should be tested using a lap-top computer and manufacturer software.

Engine Spark Plug Wires

Spark plug wires should be installed in the correct order to prevent engine misfire, stalling, backfiring, or other issues.

RAM

RAM stands for Random Access Memory.

Acetylene Cylinders

Acetylene is stabilized by acetone in an acetylene cylinder.

Fuel Injection Systems

In a fuel injection system, closed loop functioning is based on the oxygen content of exhaust gases, fuel pressure, and volume of intake air.

Fuel Consumption

The cost of fuel needed to travel a certain distance can be calculated by multiplying the fuel consumption per 100km by the cost of fuel per litre.

Truck and Transport Mechanic Exam Questions

Low Lubricant Levels

If the lubricant level in the differential, steering reservoir, or gearbox is very low, fill to the proper level with the specified lubricant.

Measuring Main Bearing Clearance

To measure main bearing clearance using plastigage, install plastigage, lubricate the journal, torque the bearing cap, and read the clearance.

Electric Transformer

The ratio of the primary winding to the secondary of an electric transformer with 240 turns in the primary winding and 15 turns in the secondary winding is 240/15.

Sealed Bearing Temperature

The maximum allowable temperature for a sealed bearing is 160ºF.

Hazardous Materials on a Bus

Emergency drug shipments, tear gas, and emergency hospital supplies should never be transported with passengers on a bus.

Engine, Suspension, and Driveline Problems

Technician 2 is correct: start with simple inspections first to ensure that you have not overlooked something, and use the scan tool for further clarification.

Road Test for Diesel Engine Low Power

During a road test, fuel temperature and exhaust back pressure are evaluated to certify that a diesel engine has low power.

Low Amperage Draw and Sluggish Cranking Speed

A low amperage draw and a sluggish cranking speed can be caused by high mechanical resistance, a shorted armature, or high starter cable resistance.

Failure of Conveyer Bearings on a Paver

Lack of grease can lead to the failure of the conveyer bearings on a paver.

Engine Noise

An engine noise that sounds like a knock at the side of the engine, is louder when the engine is cold, and goes away or is reduced when the engine reaches operating temperature, is likely caused by a wrist pin or piston slap.

Seat Belt System Evaluation

The protocol for evaluating or fixing seat belt systems after a collision is to inspect the belt and buckle operation, then inspect the stitching at the energy management loops.

Coolant Loss

A coolant loss, recently supplied to a heated engine, with white smoke emitted from the exhaust when the engine is under stress, indicates a problem.

Instrument Cluster Warning Gauges

If all warning gauges in the instrument cluster read high, the cause is not a shorted ground.

Balancing Coil Gauge

When a balancing coil gauge indicates a high reading, the sending unit will have low resistance.

Rebuilding Dual Countershaft Transmission

The next step after rebuilding the auxiliary part of a dual countershaft transmission is to install the high/low range synchronizer.

Power Steering Box Adjustment

The proper adjustment sequence for a power steering box is to adjust poppets, sector shaft endplay, and input shaft preload.

Oxygen Sensor Testing

A quality O2 sensor will have a voltage range of 0.200 volts to 0.800 volts during oxygen sensor testing.

Car Battery

A 12-volt car battery has six cells connected in series.

Air Conditioning Performance Test

If the compressor outlet is hot during an air conditioning performance test, it may indicate an overcharged system.

Engine Oil Circulation

The engine's oil circulates from the sump to the oil pump to the bearings to the filter.

Inflating a Wheel and Tire Assembly

When inflating a wheel and tire assembly, cage or confine the wheel and tire assembly and use a remote fill/deflate device.

Electronic Control System

Before opening a connection in the sensor harness of an electronic control system, ensure the key switch is turned off.

HEUI Fuel System

A HEUI fuel system can be difficult or impossible to start if the engine oil pressure is high, the engine oil level is high, or there is a leaking injector oil return.

Hydrostatic Drive System

If a hydrostatic drive system functions in backward but not forward, it may be caused by servo pistons being scored, the drive motor being overloaded, or low charge pump pressure.

Linear Positioner Circuit

The first step to take when a linear positioner circuit malfunctions is to remove the air bag module first and set it aside for safety.

Check Engine Light

If the yellow check engine light is illuminated, repair the system for active fault codes.

Spark Plug Wires

If the spark plug wires are not installed in the correct order, the engine will misfire upon starting.

RAM

RAM stands for Random Access Memory.

Acetylene Cylinder

Acetylene in a cylinder is stabilized by acetone.

Closed Loop Functioning in Fuel Injection

The basis for closed-loop functioning in a fuel injection system is the oxygen content of exhaust gases.

Fuel Cost

The cost of fuel needed to travel 620km, using premium unleaded fuel at 1.50perlitre,withafuelconsumptionof12litresper100km,is1.50 per litre, with a fuel consumption of 12 litres per 100km, is 1.50perlitre,withafuelconsumptionof12litresper100km,is112.

Electrical Panel

A huge single panel, frame, or assemblage of panels on which switches, overcurrent and other protection devices, buses, and often instruments are placed on the face, back, or both is called a panelboard.

Hazardous Materials Transportation

Dual tires should be inspected every 50 miles or 3 hours when transporting hazardous materials.

Engine Sensors

The Coolant sensor is used to assess engine temperature.

Descending a Steep Slope

The most effective and secure technique for descending a steep slope is to change to a lower gear.

Battery Electrolyte

The electrolyte of a battery is a combination of water and sulfuric acid.

Engine Performance

If the valve timing is delayed due to a stretched timing belt in a single overhead camshaft engine, low RPM power will be reduced.

Electrical Connection Testing

The integrity of an electrical connection should be tested for tightness, then a voltage drop should be performed across the connector.

Cylinder Head Bolts

Cylinder head bolts are usually lubricated with silicone spray.

Emergency Braking

To prevent a collision when driving a double trailer, use controlled or stab braking.

Endurance Braking Systems

Endurance braking systems are beneficial for descent of long hills.

Fuel Gauge

If a fuel gauge reads full, the most likely cause is a wire to the sending unit being grounded or a float stuck in the up position.

Hydrostatic Axial Piston Drive Motor

A restricted inlet line or filters can cause the hydrostatic axial piston drive motor to fail completely.

Fuel Consumption

Implementing engine braking is a method to reduce fuel consumption.

Slack Adjusters

Slack adjusters are an adjusting nut on the backside of the brake drum used for adjusting the brakes.

Driveline Vibration

Loose connection on the oil inlet side of the pump can produce vibration in the driveline.

Torque Transmission

If 180 foot-pounds of torque are input at the input shaft of the transfer case, 162 pounds of torque are transmitted to the driving pinion of the front axle of a four-wheel-drive car in low range (ratio of 1.8:1).

Braking Methods

Engine braking consumes the least amount of fuel.

Backing Behind a Trailer

Before backing behind a trailer, the air brakes must be off, and the tractor protection valve must be normal.

Trailer Breakaway

If the trailer breaks away from a combination vehicle, separating both air lines, the trailer brakes will activate and the air lines will separate.

Wire Continuity

A logic probe can be used to check the continuity of wires that carry digital signals.

Fuel Systems

The two types of fuel systems for engines with spark ignition are carburetor and fuel injection.

Electrical Gauges

The majority of electrical gauges rely on battery-regulated voltage.

Refrigerant Removal

The first stage in removing refrigerant from an air conditioning system is to identify the type of refrigerant.

Diesel Engine Performance

During a road test, fuel temperature and exhaust back pressure are evaluated to certify that a diesel engine has low power.

Battery Condition

A low amperage draw and sluggish cranking speed can be caused by a shorted armature.

Conveyor Bearing Failure

Lack of lubricant on the chains can lead to the failure of the conveyor bearings on a paver.

Engine Noise

A knock at the side of the engine that is louder when the engine is cold and goes away or is reduced when the engine reaches operating temperature is likely caused by piston slap.

Seat Belt Inspection

The protocol for evaluating or fixing seat belt systems after a collision involves inspecting belt and buckle operation, then inspecting the stitching at the energy management loops.

Coolant Loss

A recent coolant supply to a heated engine can cause coolant loss.

Indicator Lamp Malfunction

The code PO135 is determined by a bad connection at the ground terminal of the oxygen sensor heater circuit.

Faded or Failing Brakes

Faded or failing brakes can be caused by overheating, low air pressure, and not relying on the engine braking effect.

Valve Stem Height Adjustment

The right procedure for adjusting excessive valve stem height is grinding material from the valve tip.

Hydrostatic System Failure

Contamination can cause the primary pump of a hydrostatic system to break shortly after installation.

Universal Joints and Engine Mounts

Over-lubricated universal joints can lead to crossed plug wires and bad engine mounts.

Sensors and Battery Components

A potentiometer is a sensor that delivers positional information, like a power seat sensor.
Sulphuric acid and water are common components of a battery.
Adhesion promoter is also a component of a battery.

Brake Systems

Constantly using the brakes on a lengthy descent may lead to brake fade or wheel lockup.
The mechanism that applies and releases the brakes when the brake pedal is depressed is the emergency parking service.

Engine Cooling Systems

Engines that use reverse cooling pump the coolant from the engine block into the radiator outlet.
A V-type engine has two crankshafts.
In a hydraulic system, the majority of the unused energy is converted into heat.

Air Conditioning Systems

The first stage in removing refrigerant from an air conditioning system is to identify the type of refrigerant.

Fuel Systems

The two types of fuel systems for engines with spark ignition are carburetor and fuel injection.

Electrical Systems

The majority of electrical gauges rely on regulated voltage from the battery and alternator.
A logic probe is a tool that can be used to check the continuity of wires that carry digital signals.

Braking Methods

The braking method that consumes the least amount of fuel is engine braking.

Trailer Braking Systems

Before backing behind a trailer, the tractor protection valve must be normal and the trailer brakes must be locked.

Refrigerant Removal

The first stage in removing refrigerant from an air conditioning system is to identify the type of refrigerant.

Cooling System Pressure Test

During a cooling system pressure test, a gradual decrease in pressure may indicate a cylinder head gasket leak or a cracked cylinder head.

Brake Deterioration

Signs of deteriorating brakes include having to push harder on the brake pedal to control speed on a downgrade, or feeling spongy when pressure is applied to the pedal.

Vehicle Overheating

A vehicle is most likely to overheat due to a clogged radiator or restricted heater core.

Piston Installation

To install an oversized piston, the cylinder should be bored to the actual piston size, then honed for clearance.

Indicator Lamp Malfunction

A code PO135 indicates a problem with the O2 sensor heater circuit, bank 1, sensor 1.

Faded or Failing Brakes

Faded or failing brakes can be caused by overheating, low air pressure, and not relying on the engine braking effect.

Valve Adjustment

To adjust excessive valve stem height, the valve seat should be ground to provide clearance.

Hydrostatic System Failure

Contamination is a common cause of primary pump failure in a hydrostatic system.

Alternating Current Signal

The frequency of an alternating current signal is determined by the number of cycles per unit of time.

Automatic Transmission Maintenance

Clutch pack clearances must be measured before replacement in automatic transmission maintenance.

Camshaft Position Sensor

The camshaft position sensor provides information to the PCM to determine injection and spark timing.

Planetary Gear Set

To decrease the gear ratio in a planetary gear set, the sun gear must be held, and the carrier assembly must be the output member.

Alternator Magnetic Field

The magnetic field inside an alternator is produced by the rotor and stator.

Coolant Service Check

To do a service check on the coolant, the pH level, electrolytic level, and concentration should be checked using a hydrometer.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge of CDL regulations and safety procedures for transporting hazardous materials, including vehicle inspection and engine maintenance.