Fifth Wheel safety

The Fifth wheel is a source of safety concern in two major areas, 1.injury to the operator and 2.damage or injury caused by dropped trailers. In this module we will cover both of these areas and at the end there will be a small quiz.

Part 1 - Injury to the operator

One of the most common causes of back injury in the workplace for truck drivers is improper use of the 5th wheel. More specfically, pulling the release on the fifth wheel.

Prevention Starts in the Cab.
The most common cause of a fifth wheel being difficult to release is tension against the jaws from the kingpin. To prevent this, when you have the trailer in position to drop, set the trailer brakes, push back slightly against the trailer with the tractor and then set the tractor brakes. This is especially true if you are facing downhill.

Having and Using the Proper Equipment.
Making sure you have a good fifth wheel puller along with a good pair of gloves should be part of your pre-trip inspection.

Required Tools

The use of a puller is necessary if you are going to use the safest possible stance and posture while pulling on the release. Bending over and reaching in for the handle without a release is an awkward and unnatural position and adds strain on your shoulder, neck and back.

Proper Stance and Posture
When pulling on the puller, stand as erect as possible while facing the trailer. This puts you in the best “body mechanics” position to pull on the release.
Larry doing it wrongLarry doing it right
DO NOT JERK ON THE PULLER! Use a steady pull. If you jerk hard, and the fifth wheel does not release, then the shock is absorbed by your body, namely your shoulders and back. Second, if the puller were to slip off the release handle when you jerk, you could end up on the ground, again with an injury.

Raise the Trailer if Necessary/Get Help.
If you have followed the above steps and still cannot get the fifth wheel to release try cranking up the trailer a bit to help release the pressure. If this does not work, you may need to find someone to assist you. Have them apply a steady pulling pressure to the release handle (using a puller) while you GENTLY apply backpressure with the tractor.

It Still will not Release?
In this case there may be a mechanical problem or the fifth wheel mechanism may be clogged up with sand/de-icer, etc. At this point you need to contact the shop for their recommendation.

Part 2 - Injury or damage due to dropped trailers

Every year, we seem to have several accidents involving dropped trailers that are not securely coupled. In each case, the fifth-wheel coupling was mechanically sound, but not properly secured.

Visual fifth wheel checks must be completed with each and every hook. This is especially important during winter and spring, when road chemicals and sand can accumulate and create grit in the fifth-wheel locking mechanism. To prevent an unintentional release of the fifth-wheel, the driver must make a visual check of the fifth-wheel components, including:

1) Release handle completely pushed in. No tension on the release handle or spring.
no tension on spring or handle

2) Lock nut on front of fifth wheel plate tight against the front of fifth wheel.

no gap between trailer and 5th wheel

3) Safety pin moved toward center of fifth wheel.

4) No gap between top of fifth wheel plate and trailer plate.

no gap between trailer and 5th wheel

5) Fifth wheel jaws locked firmly around trailer king pin, with the kingpin collar below the jaws.

Jaws closed

6) A sixth visual check includes looking at the openings in the body of the fifth-wheel where the jaws retract when open. Here you can check to see the yoke has moved back and blocked the backside of the jaws, locking them closed. In some low profile fifth-wheels these openings can be difficult to see and a flashlight is necessary.

Silver Eagle dollys (Con-Gear) - we are now adding a new style of Dolly manufactured by Silver Eagle.

The steps are similar to described above accept, as you can see in the image below, the release handls in the front, (no puller is required) and there is no front nut.

The Handle position and the jaw inspection holes are illustrated in the above picture. These two piece along with inspecting that the jaws are closed and there is not gap between the fith wheel and trailer plate help insure no dropped trailers occur.

Simply doing a few of these checks is not enough. Every time you hook up to a trailer, whether single or doubles/triples, you must do a complete “visual check” of the 5th wheel.

Many drivers believe a tug test is all you need to verify that you are properly coupled.
A tug test is not completely reliable, friction and the weight of the trailer may temporarily hold the trailer. In some instances, the coupling has held for miles before the fifth wheel jaws gave way.

The other common mistake is relying on "checking the jaws" as your primary check.
Often times the jaws will appear closed until the tractor pulls away and the pin opens them.

A six point visual check of the fifth-wheel must be completed to ensure the latch mechanism is completely secured. Oak Harbor maintenance and the 5th wheel manufacturer (Holland Hitch) have demonstrated that if each of these checks is completed, the jaws cannot reopen.

Dropped trailers should always be a serious concern, due to the likelihood or potential for serious multiple vehicle accidents or rollovers. Many companies have adopted a zero tolerance policy for dropped trailers; drivers are immediately terminated regardless of the situation.


Click here to take the quiz