Not only can these parts be damaged by the weight of the vehicle, but they can also
cause severe injury to you when they let loose.
Never use a hydraulic floor jack to move something heavier than it is designed for.
Always check the rating of the floor jack and also the jack stands to be used on the
vehicle.
Then, verify that the vehicle weight is below this rating. The (GVW) gross vehicle weight
is in your owner's manual and also on the driver's side front door jam on most
automobiles.
Safety stands, also called jack stands, are supports of various heights that sit on the
floor. Make sure the surface they sit on is strong, flat, and level.
Concrete is preferred, and blacktop areas could be unsafe due to softness. Use 1
�
-
inch thick lumber under the jack stands on blacktop areas so they do not sink into the
surface.
Safety stands are placed under a sturdy chassis member, such as the frame or axle
housing, to support the vehicle's weight.
Once the safety stands are in position, the hydraulic pressure in the jack should be
slowly released until the weight of the vehicle is on the stands.
Like floor jacks, safety stands also have a capacity rating. Always use a jack stand of
the correct size and weight rating.
Never put yourself under a vehicle when only a hydraulic jack supports it. Rest the
vehicle on the safety stands before moving around the vehicle.
The recommended reason for removing the hydraulic floor jack after it is safely
supported on the stands is that this will eliminate a hazard, such as a jack handle
sticking out into a walkway.
A hydraulic floor jack handle that is bumped or kicked can cause a tripping accident or
the vehicle to fall.
2.1.3 Lift and Hoist Safety
Raising a heavy-duty truck on a lift requires special care. Adapters and hoist plates
must be positioned correctly on twin-post and rail-type lifts to prevent damage to the
underbody of the vehicle. There are specific lift points to use where the weight of the
vehicle is evenly supported by adapters or hoist plates. The correct lift points can be
found in the vehicle's service manual. Before operating any lift or alignment machine,
carefully read the manufacturer's literature and understand all the operating and
maintenance instructions.
Heavy subcomponents, such as engines and transmissions, should be removed using a
chain hoist or jacks. To prevent serious injury, chain hoists or the jacks must be properly
attached to the parts being lifted. Use equipment of sufficient strength rating for the
object being lifted or lowered.
The following are some general rules for using jacks, lifts, frame machines, and hoists:
•
Do not allow anyone to remain in a vehicle when it is being raised.
•
Make certain you know how to operate the equipment and know its limitations.
•
Never overload a lift, hoist, or jack.
NAVEDTRA 14050A
9-15