CSLB General Building (B) — All Questions

When inspecting the coupling system of a combination vehicle, what should you check about the fifth wheel mounting?

• a.That mounting bolts and brackets are secure and none are missing or broken✓
• b.That it is painted to match the cab
• c.That the fifth wheel is completely dry
• d.That it is tilted forward

During inspection you must check that the fifth wheel is securely mounted, with no missing or broken mounting bolts, brackets, or welds. A loose or cracked fifth wheel mount can fail under load. This is a critical part of the combination vehicle coupling inspection.

What are you checking for when you inspect the trailer air lines (glad hands) during a pre-trip?

• a.Only their color
• b.That they are not cut, cracked, worn, or leaking, and are properly connected and secured✓
• c.That they are wrapped around the frame
• d.That they are as long as possible

You should inspect the air lines for cuts, cracks, wear, or leaks, and make sure they are securely connected and not dragging or tangled. Damaged air lines can cause a loss of braking. Properly supported lines also avoid chafing against the frame.

When inspecting the kingpin and fifth wheel coupling, what condition indicates a problem?

• a.A greased fifth wheel plate
• b.Locking jaws closed around the kingpin shank
• c.A visible gap between the upper and lower fifth wheel plates✓
• d.The safety catch engaged over the release lever

A gap between the upper and lower fifth wheel plates indicates an improper coupling that could fail. There should be no space between the plates and the locking jaws should be closed around the shank. Finding a gap means you must recouple before driving.

During a combination vehicle inspection, what should you check about the landing gear?

• a.That it is greased and turning
• b.That it is halfway down
• c.That the crank spins freely
• d.That it is fully raised, the crank handle is secured, and no parts are missing, damaged, or bent✓

You should confirm the landing gear is fully raised, the crank handle is secured in place, and there are no missing, bent, or damaged parts. Landing gear that is not fully up can catch on obstacles or railroad crossings. Damaged legs may collapse when supporting the trailer.

When inspecting the electrical connection between tractor and trailer, what should you verify?

• a.That the electrical cord is firmly plugged in, secured, and not damaged or dragging✓
• b.That the cord is unplugged for safety
• c.That the cord matches the paint color
• d.That the cord is wrapped around the kingpin

You should verify the electrical (light) cord is firmly seated in its socket, secured with the safety latch if equipped, and free of cuts or fraying. A loose or damaged cord can cause the trailer lights to fail. It should also be routed so it does not drag or chafe.

How can you test whether the trailer emergency brakes work during an inspection?

• a.By revving the engine in neutral
• b.By charging the trailer air, shutting off the tractor engine, then pulling the trailer air supply valve out and checking the trailer brakes apply✓
• c.By bouncing the trailer
• d.By disconnecting the light cord

To test the trailer emergency (spring) brakes, charge the air system, then pull out the trailer air supply valve (or let air bleed) and confirm the trailer spring brakes set. You can then apply the tractor gently in low gear to confirm the trailer stays put. This verifies the emergency braking function before driving.

When checking the trailer service brakes during a combination vehicle inspection, what should you do?

• a.Only look at the brake lights
• b.Rev the engine and listen
• c.Charge the system, release the parking brakes, move slowly, and apply the brake pedal to confirm the vehicle stops and does not pull to one side✓
• d.Disconnect the glad hands

To check service brakes, charge the air system, release the parking brakes, roll forward slowly, and press the brake pedal. The vehicle should stop straight without pulling to one side and without unusual feel. Pulling or a delayed stop can indicate a brake problem on the tractor or trailer.

What should you inspect on the trailer's tires and wheels during a pre-trip?

• a.Only the color of the rims
• b.Only the front tires
• c.That the tires are the newest brand
• d.That tires have proper inflation and tread, no cuts or bulges, and wheels have no missing, loose, or damaged lug nuts or cracks✓

You should inspect all trailer tires for proper inflation, adequate tread depth, and freedom from cuts, bulges, or uneven wear. Wheels and rims must have no cracks, and lug nuts must be present and tight with no rust streaks indicating looseness. Trailer tires are easy to overlook but critical to safety.

Why should you check the air line connections between the tractor and trailer for leaks?

• a.Because leaking air lines can cause loss of braking ability in the combination vehicle✓
• b.Because leaks make the horn quieter
• c.Because leaks change the tire pressure
• d.Because leaks affect the paint

Air line leaks reduce the air pressure available for braking and can lead to brake failure. You should listen and feel for leaks at the glad hand connections and along the hoses during inspection. Any significant leak must be repaired before driving.

When inspecting a combination vehicle, why must you check that the trailer is not overloaded or unbalanced?

• a.Because overloading changes the paint color
• b.Because improper weight distribution affects braking, handling, and can raise the center of gravity and rollover risk✓
• c.Because it changes the trailer length
• d.Because it lowers the landing gear

An overloaded or poorly balanced trailer affects braking distance, steering, and stability. Loads that are too high or shifted raise the center of gravity and increase rollover risk. Confirming proper weight and secure cargo is part of a safe combination vehicle inspection.

What should you look for when inspecting the sliding fifth wheel (if equipped)?

• a.That it is welded solid
• b.That it slides freely while driving
• c.That the slide is locked in place and the locking pins are fully engaged✓
• d.That it is removed

On a sliding fifth wheel you must confirm the slide is locked in position and the locking pins are fully engaged, not just resting. An unlocked slide can move under braking and shift weight or cause a coupling failure. Also check that the slide rails and stops are not cracked or worn.

During the walk-around inspection of a trailer, what should you check about the trailer lights and reflectors?

• a.Only that the headlights work
• b.Only that reflectors are shiny
• c.That the trailer has no lights
• d.That all required clearance, marker, brake, tail, and turn lights work and reflectors are present and clean✓

You should confirm all required trailer lights, including clearance, marker, brake, tail, and turn signals, are working, and that reflectors are present and clean. Trailer lights make the rig visible to other drivers, especially at night. Burned-out lights or missing reflectors are common violations.

When inspecting the trailer's suspension system, what should you look for?

• a.Cracked or broken spring hangers, missing or broken leaves, and loose or damaged air suspension parts✓
• b.Only the tire pressure
• c.Only the mud flaps
• d.The color of the frame

You should inspect the trailer suspension for cracked or broken spring hangers, missing or shifted spring leaves, and any loose or leaking air suspension components. Suspension failures can affect handling and load stability. Also check U-bolts, shock absorbers, and mounting hardware.

What is the purpose of checking the trailer's air tank drain and slack adjusters during inspection?

• a.To confirm the tank is painted
• b.To ensure the brakes are properly adjusted and moisture is drained so brakes work reliably✓
• c.To check the trailer length
• d.To grease the kingpin

Draining the trailer air tank removes moisture and oil that can damage the system, and checking slack adjusters confirms the brakes are within proper adjustment. Out-of-adjustment brakes reduce stopping power. These checks help ensure the trailer brakes perform correctly.

Why should you check that the trailer doors, cargo securement, and header board are secure during inspection?

• a.To improve fuel economy
• b.To make the trailer lighter
• c.So cargo cannot shift or fall out and doors stay latched while driving✓
• d.To change the trailer color

You should confirm trailer doors are securely latched and cargo is properly secured so nothing shifts or falls during transit. A shifting load affects handling and can raise rollover risk, while an unlatched door can release cargo onto the road. Securement devices, tie-downs, and the header board should be checked.

When performing an air brake check on a combination vehicle, why do you test the tractor protection valve and trailer air supply valve?

• a.To grease the valves
• b.To change gear ratios
• c.To check the paint
• d.To confirm that if trailer air pressure drops too low, the valves close and protect the tractor's air supply✓

The tractor protection valve and trailer air supply valve are tested to confirm they will close automatically when air pressure drops to a low level, typically between 20 and 45 psi. This protects the tractor's braking system if a trailer air line breaks. Confirming this function is a key part of the combination air brake check.

What should you check about the mounting of the fifth wheel skid plate and the trailer apron?

• a.That the trailer apron sits flat on the fifth wheel and there is no gap or damage to the plates✓
• b.That the apron is removed
• c.That the plate is unpainted
• d.That the apron is loose for flexibility

You should confirm the trailer apron rests flat and fully on the fifth wheel skid plate with no gap or bending. Damage or a gap indicates a bad coupling or worn parts that could fail. The plates must contact firmly for a safe, stable connection.

During inspection, what should you check about the trailer's mud flaps and rear-end protection (ICC bumper)?

• a.Only their color
• b.That they are present, securely mounted, and not damaged or missing✓
• c.That they drag on the ground
• d.That they are removed to reduce weight

You should verify the mud flaps and rear impact guard (ICC/DOT bumper) are present, securely mounted, and undamaged. Mud flaps reduce spray to other vehicles, and the rear guard helps prevent underride in a collision. Missing or broken components are violations.

When you check air lines during a combination inspection, which lines are you connecting and inspecting?

• a.Only the fuel line
• b.Only the electrical line
• c.The service (blue) air line and the emergency (red) air line✓
• d.The coolant and oil lines

On a combination vehicle you inspect and connect the service air line, often blue, and the emergency air line, often red. The service line carries air for normal braking, and the emergency line supplies the trailer reservoir and controls the spring brakes. Both must be secure and leak-free.

Why is it important to check the trailer registration, load limits, and that the trailer is not leaking (for tankers or vans) during inspection?

• a.To increase speed
• b.To reduce the number of tires
• c.To change the fifth wheel
• d.To ensure the vehicle is legal, safely loaded, and not spilling cargo or fluids on the road✓

You should confirm the trailer paperwork is in order, the load is within weight limits, and there are no leaks from the cargo or vehicle systems. Overweight or leaking trailers are illegal and dangerous. These checks keep the rig compliant and prevent hazards to other road users.