Hitching and Unhitching a Tractor and a Semi-Trailer +6Quebec · CDL · English

A heavy vehicle driver must master the correct technique for hitching a semi-trailer. Any error during the hitching process or using the wrong method can cause an accident or equipment failure. You must follow the same steps and proceed in the same manner each time you hitch to save time and ensure safe driving.

• ✓Always follow the same steps in the same manner each time you hitch a semi-trailer
• ✓Any error or wrong method during hitching can cause an accident or equipment failure
• ✓Mastering correct hitching technique is essential for a heavy vehicle driver

Before hitching, inspect the fifth wheel to ensure it is well lubricated, undamaged, firmly anchored, and correctly positioned for hitching. In winter, remove accumulated snow so the fifth wheel locks correctly.

• ✓Ensure the fifth wheel is well lubricated and mechanisms show no sign of damage
• ✓Ensure the fifth wheel is firmly anchored to the tractor chassis frame
• ✓The fifth wheel must be tilted down towards the rear with jaws completely open
• ✓In winter, remove any accumulated snow to ensure the fifth wheel locks correctly

Check the surroundings to ensure a safe hitching location. Line the tractor up in a straight line with the semi-trailer, roll down the window to hear, and check both sides in the mirrors. Do not hitch until the tractor is lined up, then back up slowly ensuring the axle fits under the semi-trailer.

• ✓Line the tractor up in a straight line with the semi-trailer before hitching
• ✓Roll down the window to hear and check both sides in the outside rearview mirrors
• ✓Do not hitch the semi-trailer until the tractor is lined up with it
• ✓Back up slowly and make sure the axle fits under the semi-trailer

The upper coupler plate of the semi-trailer should be slightly lower than the fifth wheel plate at its pivot point. If lower, the semi-trailer is slightly raised when hitched, making it easier for the locking mechanism to engage. Adjust height using the landing gear or tractor suspension.

• ✓The upper coupler plate should be slightly lower than the fifth wheel plate at its pivot point
• ✓If too high, lower the semi-trailer using the landing gear
• ✓If too low, lower the tractor's suspension or raise the semi-trailer using landing gear
• ✓Check the condition of the kingpin and upper coupler plate; remove the latch if necessary

Whenever stopping during hitching, put on the tractor's parking brake, shift into neutral, switch on hazard lights and parking lights, and climb down from the cab using three support points.

• ✓Put on the tractor's parking brake and shift into neutral before leaving the cab
• ✓Switch on hazard lights and parking lights
• ✓Always climb down from the tractor cab using three support points

Back the tractor up slowly under the semi-trailer, checking mirrors, until the kingpin is positioned inside the fifth wheel. This must be done correctly so the locking mechanism engages and to prevent the kingpin striking hard against the fifth wheel. Test the lock by trying to move forward and stop as soon as you feel resistance.

• ✓Back up slowly until the upper coupler kingpin is positioned inside the fifth wheel
• ✓Perform correctly to ensure the locking mechanism engages and prevent kingpin striking hard
• ✓Check the lock by trying to move the tractor forward; stop as soon as you feel resistance
• ✓Before climbing down, switch on the semi-trailer's hazard, parking and clearance lights

Look under the semi-trailer to check the kingpin is fully inserted into the jaws (use a flashlight) and that the fifth wheel locking mechanism is in the lock position. If it does not lock, ask a mechanic. Connect indicator lights and brake hoses safely, raise the landing gear, and turn on air suspension if needed.

• ✓Check the kingpin is fully inserted into the jaws, using a flashlight if necessary
• ✓Check the fifth wheel locking mechanism is in the lock position; if it does not lock, ask a mechanic
• ✓Connect indicator lights and brake hoses ensuring they cannot be damaged by vehicle movements
• ✓Raise the landing gear and place the crank in the bracket

Put on both tractor and semi-trailer parking brakes, shift into neutral, and climb down using three support points. Check the semi-trailer condition, lower the landing gear until firmly braced against the ground, unhook brake hoses and indicator lights connecting them to dummy couplers, then pull the fifth wheel release lever(s) to the open position.

• ✓Put on the tractor and semi-trailer parking brakes and shift into neutral
• ✓Lower the landing gear until it is braced firmly against the ground
• ✓Unhook brake hoses and indicator lights and connect them to the dummy couplers behind the cab
• ✓Pull the fifth wheel release lever(s) until in the open position

Move the tractor forward approximately 15 cm to release the kingpin and stop. Lower the tractor's air suspension and move forward slowly, stopping while the last axle is still under the semi-trailer so it will be supported if the landing gear fails or sinks. Check the semi-trailer is immobilized before moving away, then turn the suspension back on.

• ✓Move the tractor forward approximately 15 cm to release the kingpin, then stop
• ✓Lower the tractor's air suspension and move forward slowly
• ✓Stop while the last axle is still under the semi-trailer to support it if the landing gear fails
• ✓Check that the semi-trailer is immobilized before driving forward or climbing down

Before hitching a semi-trailer, the tractor's fifth wheel must be inspected to ensure it is safe and ready to receive the kingpin. Any error at this stage can cause an accident or equipment failure.

• ✓Make sure the fifth wheel is well lubricated with no signs of damage
• ✓Make sure the fifth wheel is firmly anchored to the tractor chassis frame
• ✓Fifth wheel must be tilted down towards the rear with jaws completely open
• ✓In winter, remove any accumulated snow so the fifth wheel locks correctly

The tractor must be correctly lined up with the semi-trailer before backing under it, using mirrors and hearing to confirm alignment on both sides.

• ✓Line the tractor up in a straight line with the semi-trailer
• ✓Roll down the window and check both outside rearview mirrors before backing up
• ✓Do not hitch the semi-trailer until the tractor is lined up with it
• ✓Back up slowly and ensure the axle fits under the semi-trailer

Backing under the semi-trailer must be done correctly to prevent the kingpin from striking the fifth wheel and to ensure the locking mechanism engages.

• ✓Back up slowly while checking outside mirrors until the kingpin is inside the fifth wheel
• ✓Check the fifth wheel is locked by trying to move the tractor forward and stopping at resistance
• ✓Put on the parking brake and shift into neutral
• ✓Before climbing down, switch on the semi-trailer's hazard, parking and clearance lights
• ✓Always climb down using three support points

After hitching, a physical inspection under the trailer confirms the kingpin is fully engaged and the lock is set, followed by connecting services and raising the landing gear.

• ✓Look under the semi-trailer to confirm the kingpin is fully inserted into the jaws (use a flashlight)
• ✓Confirm the fifth wheel locking mechanism is in the lock position; if it does not lock, call a mechanic
• ✓Connect indicator lights and brake hoses so they cannot be damaged by movement
• ✓Raise the landing gear and stow the crank in the bracket
• ✓Turn on the semi-trailer's air suspension by hand if necessary

Choose a firm, level location before unhitching so the ground can support the semi-trailer weight, then prepare the trailer and release the fifth wheel.

• ✓Choose ground firm and flat enough to support the semi-trailer's weight
• ✓Line the tractor up straight, set both parking brakes and shift into neutral
• ✓Lower the landing gear until it is braced firmly against the ground
• ✓Unhook brake hoses and indicator lights and connect them to the dummy couplers behind the cab
• ✓Pull the fifth wheel release lever(s) to the open position

The tractor is moved forward slightly to release the kingpin, its suspension lowered, then driven out while keeping the last axle under the trailer for safety.

• ✓Move the tractor forward approximately 15 cm to release the kingpin, then stop
• ✓Lower the tractor's air suspension and move forward slowly
• ✓Stop while the last axle is still under the semi-trailer to support it if landing gear fails
• ✓Confirm the semi-trailer is immobilized before driving fully clear
• ✓Slowly move away and turn the tractor's suspension back on

Before unhitching, ensure you are in a good spot. Choose an area where the ground is firm enough and flat enough to support the weight of the semi-trailer, preventing the landing gear from sinking.

• ✓Choose an area where the ground is firm enough and flat enough to support the semi-trailer
• ✓Line the tractor up straight with the semi-trailer before unhitching

To maintain stability, the heavier loaded semi-trailer must be positioned closest to the tractor, except when weights are nearly equal.

• ✓Semi-trailer with greatest total loaded mass must always be hitched to the tractor
• ✓Exception applies where weight difference between the two semi-trailers is less than 10%

For all types of double trains, the length of the second semi-trailer is strictly regulated between a minimum and maximum measurement to ensure stability and legal compliance.

• ✓Maximum length of second semi-trailer is 16.2 m
• ✓Minimum length of second semi-trailer is 12 m
• ✓Applies to all types of double trains

An LCV must be equipped with a device that tracks the driver's behaviour and records driving data. This is used by enforcement officers to verify safe operation.

• ✓LCV must have a device to track driver's behaviour
• ✓Device must record wide variations in speed
• ✓Device must record date, time and speed data

A warning sign with the word 'LONG' must be placed on the rear of the second semi-trailer to alert other road users to the vehicle's length. Specific size and condition standards apply.

• ✓Sign must bear the word 'LONG' and be placed on rear of second semi-trailer
• ✓Sign must be 230 to 245 cm by 30 cm in size
• ✓Sign must be rigid and free of any object, substance or dirt
• ✓Sign not required for an LCV made up of tractor, semi-trailer and tandem axle dolly with no semi-trailer hitched

To ensure the LCV tracks properly and safely, neither semi-trailer may swing excessively out of line with the tractor when travelling straight.

• ✓Neither semi-trailer may swing more than 80 mm out of line with the tractor
• ✓Limit applies to either side when travelling in a straight line

A dolly used in an LCV must have braking enhancement equipment, and C double train dollies must meet federal safety standards.

• ✓Dolly must have a pilot relay valve to boost braking signal of the second semi-trailer
• ✓For a C double train, dolly must meet section 903 of the Motor Vehicle Safety Regulation under the Motor Vehicle Safety Act

The tractor of an LCV must have a specific axle configuration and spacing measurements to ensure safe operation of the long combination.

• ✓Tractor must have a front single axle and a rear tandem axle
• ✓Interaxle spacing must be at least 3.5 m (single axle rotation axis to first tandem axle rotation axis)
• ✓Wheelbase must be 6.2 m or less (single axle rotation axis to centre of tandem axle)

The first and second semi-trailers of various train types have specific axle group requirements depending on train configuration and manufacture date.

• ✓First semi-trailer of a B train must have a tandem axle or triple axle
• ✓First semi-trailer of an A or C train must have a tandem axle, triple axle, or four-axle group with 32,000 kg load limit (class B.44 or B.45)
• ✓Second semi-trailer of all LCVs must have a tandem axle or triple axle
• ✓Interaxle spacing of tandem/triple axle must not exceed 1.85 m
• ✓First semi-trailer of A or C train made before March 1, 1997 may use any tandem/triple combination and interaxle spacing rules do not apply

Covers all coupling devices other than a fifth wheel. Inspect the components of the coupling device such as the drawbar ring and pintle hook. A converter dolly uses two types of coupling devices: a fifth wheel device and a pintle hook/drawbar ring device — both must be checked. Inspect on both sides of the combination, facing the coupling device, checking the tractor vehicle (pintle hook, locking mechanism) and the vehicle being pulled (ring, drawbar).

• ✓Defect 1.F (major): When vehicles are hitched, a coupling component is missing, improperly secured, cracked, misshapen or deteriorated to the point of risk of breakage or separation
• ✓The pintle hook locking mechanism must be in proper working order to avoid separation of the combination
• ✓A converter dolly requires checking both a fifth wheel device and a pintle hook/drawbar ring device

Check for the presence and condition of safety fasteners or coupling components (steel cables, chains, hooks, rings to which chains attach). Inspect between the tractor vehicle and the trailer. Safety fasteners are mandatory when the trailer is not equipped with emergency brakes that enable the trailer to stop if separation occurs.

• ✓Defect 1.2 (minor): A safety fastener or coupling component is missing, deteriorated, or improperly attached
• ✓Safety fasteners are mandatory when the trailer lacks emergency brakes capable of stopping it upon separation

The master cylinder reservoir must be checked to verify the service brake fluid level. Check the fluid level using the indicator on the reservoir. If there is no indicator, open the reservoir to check the fluid level. Some reservoirs require a tool to be opened. If a reservoir has two caps, both compartments must be checked. In a combination of vehicles where each vehicle has hydraulic brakes, the reservoir of each vehicle must be checked. When opening the reservoir, clean around the opening to avoid contaminants, properly replace the seal, and tighten the cap.

• ✓Major defect (18.A): master cylinder fluid level is less than one-quarter of the maximum level prescribed by the manufacturer
• ✓Minor defect (18.1): fluid level is below the minimum prescribed level or, if no indicator, more than 12.5 mm below the edge of the filler opening
• ✓If a reservoir has two caps, both compartments must be checked
• ✓In a combination of vehicles, the reservoir of each vehicle with hydraulic brakes must be checked

Check the working order of the power brake. The power brake cannot be checked using these methods if it is hydraulically assisted. For a vacuum brake booster: run engine a few seconds, stop it, pump the brake pedal several times, apply average pressure, restart engine while maintaining pressure, and check the movement of the brake pedal. For a hydraulic brake booster (electric pump): turn off engine, apply average pressure to the pedal, and listen for the electric pump working. Many school buses and some straight-body trucks use electric pump boosters.

• ✓Vacuum booster defect (18.C): the brake pedal does not go down slightly after restarting the engine
• ✓Hydraulic booster defect (18.C): the electric pump does not work when the engine is not running
• ✓The power brake cannot be checked with these methods if hydraulically assisted

Check pressure and for leaks in the braking equipment. With the engine running, press down hard (harder than a normal braking manoeuvre) on the brake pedal for at least 10 seconds and check the movement of the pedal. For some vehicles with a hydraulic brake booster, this check cannot be performed if the engine is not running.

• ✓Major defect (18.B): the brake pedal reaches the floor in less than 10 seconds
• ✓Minor defect (18.2): the brake pedal reaches the floor in 10 seconds or more
• ✓Major defect (18.B): the brake pedal has to be pumped several times to pressurize the circuit, felt by resistance in the pedal

Check the effectiveness of the service brake from the driver's compartment. Start the vehicle and drive forward slightly, press on the brake pedal, and check whether the vehicle stops quickly.

• ✓Major defect (18.D): there is a significant reduction in braking capacity
• ✓Test at low speed by driving forward slightly and pressing the brake pedal

Check the effectiveness of the parking brake from the driver's compartment with the engine running. Apply the parking brake and try to drive forward (automatic: 'DRIVE' position; manual: right gear to move forward) and check whether it holds the vehicle stationary. Then release it and slowly drive a few metres forward watching wheel rotation in the mirrors. The parking brake cannot be checked on certain heavy vehicles with automatic transmission that cannot shift into gear while the parking brake is engaged.

• ✓Defect (18.5): parking brake does not keep the vehicle from moving when driver tries to drive forward
• ✓Defect (18.5): parking brake does not let the wheels turn freely when released
• ✓Turning left and right helps check trailer/semi-trailer wheels in a combination

Check the working order of the power brake. The power brake cannot be checked using these methods if it is hydraulically assisted. For a vacuum brake booster: let engine run a few seconds, stop engine, pump brake pedal several times, apply average pressure, restart engine while maintaining pressure, and check pedal movement. For a hydraulic brake booster (electric pump): turn off engine, apply average pressure to pedal, and listen for the electric pump working. Some straight-body trucks and most school buses have a hydraulic brake booster (electric pump).

• ✓Vacuum booster defect 18.C (major): the brake pedal does not go down slightly after restarting the engine
• ✓Hydraulic booster (electric pump) defect 18.C (major): the electric pump does not work when the engine is not running
• ✓The power brake cannot be checked with these methods if it is hydraulically assisted

Check the effectiveness of the parking brake with the engine running. Apply the parking brake and try to drive forward (automatic: shift to DRIVE; manual: select right forward gear) to confirm the brake keeps the vehicle stationary. Then release the brake and slowly drive a few metres, watching wheel rotation in the mirrors. The parking brake cannot be checked on certain vehicles with automatic transmission because the transmission cannot be shifted into gear while the parking brake is engaged.

• ✓Defect 18.5 (minor): parking brake does not keep the vehicle from moving when the driver tries to drive forward
• ✓Defect 18.5 (minor): parking brake does not let the wheels turn freely when released
• ✓Turning left and right makes it easier to check trailer/semi-trailer wheels in a combination

Check the working order of the service brake warning light from the driver's compartment. Release the parking brake (only if the service brake warning light is also the parking brake warning light), turn the ignition key to 'ON' or 'START', check whether the warning light switches on, start the engine, and check whether the warning light switches off.

• ✓Defect (18.3): warning light does not switch on when the ignition key is in the 'ON' or 'START' position
• ✓Defect (18.3): warning light stays on when the engine is running
• ✓Release the parking brake first only if it shares the warning light with the parking brake

Check the working order of the parking brake warning light. Turn the ignition key to 'ON' or 'START', apply the parking brake, and check whether the warning light switches on. Then release the parking brake and check whether the warning light switches off.

• ✓Defect (18.4): warning light does not switch on when the parking brake is activated
• ✓Defect (18.4): warning light does not switch off when the parking brake is released

When performing a circle check on a school bus, use the straight-body truck method plus the additional city bus points, and inspect components specific to school buses. These include power steering belts, driver-area windows, retractable stop signs, flashing lights, and hydraulic brake systems where equipped.

• ✓Inspect the power steering belt (often present, item 5.3) and windows on both sides of and directly behind the driver's compartment (item 11.4)
• ✓Check the retractable stop sign and its flashing/alternately flashing lights (20.7), the flashing red lights and alternately flashing yellow lights (20.8), and the hydraulic brake system where equipped (section 18)

A motor coach circle check is a sight and sound check of accessible parts, following the same steps as a city bus. Due to the vehicle configuration, the suspension system may be inaccessible, and the chassis frame and body are typically monocoque and specific to this vehicle type.

• ✓Follow the same circle check steps as a city bus, checking accessible parts by sight and sound
• ✓Recognize that the suspension may be inaccessible and body components are generally monocoque type specific to motor coaches

For efficient gear shifting, the engine must reach specific RPM ranges before changing gears. The example vehicle uses defined RPM targets for the first four gears based on an idling speed of about 650 RPM and a manoeuvre requirement of 300 RPM above idle.

• ✓650 RPM for 1st gear
• ✓950 RPM for 2nd gear
• ✓1,250 RPM for 3rd gear
• ✓1,550 RPM for 4th gear

To upshift, engine speed must be about 300 RPM higher than idling speed. Shifting becomes difficult when the difference between current RPM and the RPM needed for the manoeuvre falls below the idling RPM (e.g., 800 RPM – 300 RPM = 500 RPM).

• ✓The manoeuvre requires roughly 300 RPM above idle speed
• ✓Ideal moment to shift into 2nd is when engine reaches 950 RPM
• ✓Difference lower than idling RPM makes shifting difficult

A warning sign bearing the word 'LONG' must be displayed on the rear of the second semi-trailer, meeting size and cleanliness requirements per the Special Road Train Operating Permits Regulation.

• ✓Sign must bear the word 'LONG' on the rear of the second semi-trailer
• ✓Sign must measure 230 to 245 cm by 30 cm
• ✓Sign must be rigid and free of any object, substance or dirt
• ✓Sign not required for an LCV made up of a tractor, semi-trailer and tandem axle dolly with no semi-trailer hitched

The heavier semi-trailer must be positioned directly behind the tractor for stability, unless the weight difference is minimal.

• ✓The semi-trailer with the greatest total loaded mass must always be hitched to the tractor
• ✓Exception applies where the weight difference between the two semi-trailers is less than 10%

For all types of double trains, the second semi-trailer must fall within specified length limits. This ensures proper handling and legal compliance for LCVs.

• ✓Maximum length of the second semi-trailer is 16.2 m
• ✓Minimum length of the second semi-trailer is 12 m
• ✓These limits apply to all types of double trains

An LCV must be equipped with a device that tracks the driver's behaviour. This device supports safety monitoring and enforcement compliance.

• ✓LCV must have a device to track driver behaviour
• ✓Device must record wide variations in speed
• ✓Device must record data on date, time and speed

When an LCV travels in a straight line, neither semi-trailer may deviate laterally beyond a set limit, ensuring proper tracking.

• ✓Neither semi-trailer may swing more than 80 mm out of line with the tractor to either side
• ✓This applies when the LCV is travelling in a straight line

If an LCV includes a dolly, it must have a pilot relay valve to boost the braking signal of the second semi-trailer. C double train dollies have additional federal requirements.

• ✓Dolly must be equipped with a pilot relay valve to boost braking signal of second semi-trailer
• ✓For a C double train, dolly must meet section 903 of the Motor Vehicle Safety Regulation under the Motor Vehicle Safety Act

The tractor of an LCV must have specific axle and spacing dimensions to ensure stability and legal operation.

• ✓Tractor must have a front single axle and a rear tandem axle
• ✓Interaxle spacing must be at least 3.5 m (single axle rotation axis to first tandem axle rotation axis)
• ✓Wheelbase must be 6.2 m or less (single axle rotation axis to centre of tandem axle)

First and second semi-trailers of LCVs have specific required axle configurations depending on train type (A, B, or C).

• ✓First semi-trailer of a B train must have a tandem or triple axle
• ✓First semi-trailer of an A or C train must have a tandem axle, triple axle or four-axle group with 32,000 kg load limit (class B.44 or B.45)
• ✓Second semi-trailer for all LCV types must have a tandem or triple axle
• ✓Interaxle spacing of tandem/triple axle must not exceed 1.85 m
• ✓First semi-trailer of A or C train made before March 1, 1997 may have any combination of tandem or triple axles with interaxle spacing rules not applying