Explanation: When recoupling, you must connect the dog clip to secure the kingpin release handle.

What is a lorry dog clip?

The fifth wheel coupling is used to connect a tractor unit to a trailer. It allows articulation between the tractor and trailer. A fifth wheel coupling relies on a kingpin. Also remember to connect the dog-clip which secures the kingpin release handle.

What is the kingpin release handle?

Re: Kingpin release handle It pulls the jaw back to lock out the sliding bar when you drop a trailer.

What’s the fifth wheel coupling used for?

Explanation: The fifth-wheel coupling is a device to connect the tractor unit to the trailer. It allows articulation between the tractor and trailer, and it should be regularly maintained.

How do you uncouple a trailer?

The following steps will help you to uncouple safely. STEP 1: Position Rig. STEP 2: Ease Pressure on Locking Jaws. STEP 3: Chock Trailer Wheels. STEP 4: Lower the Landing Gear. STEP 5: Disconnect Air Lines and Electrical Cable. STEP 6: Unlock Fifth Wheel. STEP 7: Pull Tractor Partially Clear of Trailer. STEP 8: Secure Tractor.

When should wheel nuts be checked on a lorry?

Explanation: Always have wheel nuts checked soon after their initial tightening. They should be tightened to the torque specified by the vehicle manufacturer.

What Colour is the auxiliary line on a lorry?

Air brake systems usually have two lines. If your system has three lines, the third is an auxiliary (blue) line. Check with the manufacturer’s instructions what this can be used for. The red line is the emergency line.

What should you hook up before backing under the trailer?

After connecting the air lines but before backing under the trailer you should: A Supply air to the trailer system, then pull out the air supply knob.

How often should a fifth wheel be checked?

Explanation: Fifth-wheel couplings need regular inspection and lubrication. This should be carried out either every 6000 miles (10 000 km) or monthly – whichever is the sooner.

What is a kingpin on a 5th wheel?

A King Pin is a round steel shaft attached to the front of a fifth wheel trailer and the fifth wheel hitch on the truck clamps around it. Most 5th wheel trailers come with the king pin already mounted to the trailer.

Why is it called a fifth wheel?

The fifth wheel got its name from its original design. They were initially invented for horse-drawn carriages in the mid-1850s. Manufacturers (who at the time built the components by hand) placed a horizontal wheel on the cargo frame or “truck” that allowed the front axle to pivot on its own.

What is the difference between a 5th wheel and a gooseneck?

Gooseneck hitches are ball hitches that are installed within the bed of a truck. These are usually used to pull industrial and horse trailers. Fifth wheel hitches are larger hitches with hinged plates that sit in the bed of their tow truck.

What does Black stand for HGV?

You may find it useful to memorise an acronym in order to remember the safe order. One such example is P-BLACK for uncoupling (remove number Plate and then engage parking Brake, lower Legs, disconnect Airlines, remove Clip and release Kingpin handle. You then use the reverse for coupling.

What is a Suzie on a lorry?

The air and electrical lines are “suspended” between the tractor unit and the trailer. ‘Suzi’ is just an abbreviation for “suspended”.

What is a Suzie lock?

Suzie Lock is a neat device which prevents trailers from being used when out of MOT or faulty, Suzielok can also be used as a management tool or a theft deterrent. Suzielok also provides a very simple and cost effect deterrent against opportunistic theft.

Why are vehicles fitted with air suspension?

Explanation: Air suspension provides a smoother journey than traditional suspension and transmits less vibration to the road surface, under-road services and nearby structures, such as bridges. It’s considered to be environmentally friendly because it reduces damage to the road network.

What’s a buffer lane?

Explanation: During high winds, one of the lanes on a high bridge might be closed to traffic to create a buffer lane. The buffer lane is kept free to prevent vehicles from being blown into the path of other road users in the next lane. The closure of this lane may cause traffic congestion and delay.

What should you do if the load on your lorry becomes insecure?

Explanation: If you become aware that any part of your load is insecure, you must stop as soon as it’s safe to do so. Resecure the load before continuing your journey.

What is the red line on a lorry?

Modern trucks have two air lines which supply the trailer with air. The first is the supply air line (red) and the second is the service air line (yellow).

When should you use exhaust brakes on a truck?

Drivers can rely only on exhaust brakes for stopping their car. Especially if the vehicle doesn’t have a very high speed, drivers can use only the exhaust brakes for slowing down and stopping their cars, reducing the wear and tear on the regular brakes.

What’s a brake retarder?

Retarders are used to further improve the braking performance on commercial vehicles. Like engine brakes, they are wear-free continuous brakes. Retarders relieve the service brake and increase the active safety and cost-effectiveness of commercial vehicles. Retarders are installed in a commercial vehicle’s drive train.

Which trailer is most likely to turn over?

Fully loaded rigs are ten times more likely to roll over in a crash than empty rigs. The rear trailer is more likely to roll over.

What might happen if the trailer is too high?

What might happen if the trailer is too high when you try to couple? If the trailer is too low, the tractor may stike and damage the trailer nose; if the trailer is too high, it may not couple correctly. If there is space something is wrong and the trailer would come loose very easily.

Why should you not use the trailer hand valve while driving?

The trailer hand valve should be used only to test the trailer brakes. Do not use it in driving because of the danger of making the trailer skid. The foot brake sends air to all the brakes on the vehicle (including the trailer(s). There is much less danger of causing a skid or jackknife when using just the foot brake.

What would happen if you overfill your engine with oil theory?

Explanation: If the engine contains too much oil, the moving parts can hit the oil surface, causing a loss of power or even damage to the engine. Excess pressure may damage oil seals, causing oil to leak onto the road, creating a slippery and dangerous road surface.

What do heated fuel lines prevent?

Explanation: In cold weather, diesel fuel can solidify as it starts to freeze. This is known as waxing. Waxing prevents the fuel from flowing properly and this can stop the engine from running.