The U.S. Occupational Safety & Health Administration (OSHA) has issued new procedure standards that should be learned and considered by those individuals who mount, demount and inflate commercial truck tires.
An inflated tire and wheel can be very dangerous if misused or worn out. These standards (No. 29, CFR Pat 1910.177) should be reviewed extensively with new dealership employees. It is very important that these standards are reviewed on a regular basis, not just during the first week after hiring the new employee.
Training on these OSHA standards must include both textbook work and a full demonstration that the employee can perform the following key procedures:
Tire mount/demount and inflation/deflation
Using restraining devices
Handling of wheels
Inflating tires when mounted on a vehicle
Installing and removing wheels from vehicles
Where to stand (to remain outside of air blast trajectory) during and after inflating a tire
Restraining devices more commonly called “safety cages” are a very important aspect of the OSHA rules when it comes to inflating tires. These safety cages must be inspected on a daily basis to ensure there is no cracking or corrosion, which can reduce their effectiveness if a tire/wheel assembly comes apart during the inflation process. These safety cages must never be bolted to the floor.
Tires must be completely deflated prior to demounting. Removing the valve core is required to ensure complete deflation. When you demount a single-piece wheel, it should always be done from the narrow ledge side of the wheel.
Wheels must be closely inspected before a tire is mounted. You are looking for rust, cracks or bent rim flanges. The bead seat areas should be thoroughly cleaned.
Of course, you must verify that the wheel size is appropriate for the specific tire, and damaged or leaky valve stems must be replaced.
A non-flammable certified lubricant will ease mounting and eliminate tire damage; apply it to both tire beads and the bead seat areas to make mounting as easy as possible. Tires going on steel wheels should be mounted from the narrow ledge side of the rim. When a tire changing machine is used, the tire must be inflated only to the minimum pressure necessary to get the tire bead into the rim flange.
A tire safety cage must always be used when inflating a commercial truck tire. The only exception is when the wheel is bolted on a vehicle while being inflated. It is critical that the person inflating the tire stay out of the wheel and air blast trajectory during the inflation process. Always use a clip-on air chuck with enough hose to ensure that the tire tech stands completely clear and away from the inflating tire.
It is permissible to inflate a tire on a vehicle providing the tire has more than 80% of the recommended tire pressure. As with inflating in a safety cage, make sure that a clip-on air chuck and ample air line can allow tire techs to stand clear from the tire assembly.
Proper techniques for vehicle jacking and lifting (when changing tires on vehicles) are not included as part of OSHA standards, but are very important when it comes to safety and should also be reviewed on a regular basis. Every year there are many injuries associated with improper jacking and lifting of a commercial vehicle.
The two types of lifting devices for commercial vehicles are hydraulic jacks and air-over-hydraulic jacks. Hydraulic jacks do require compressed air. The advantage in these devices is that they are very portable and come in just about any height to accommodate nearly every type of commercial vehicle.
Air-over-hydraulic jacks also require compressed air, also are highly portable, and also come with different height adapters to accommodate tractors and trailers.
The most critical item in the process is for the technician to ensure that the lifting capacity of the device is greater than then weight of the axle being lifted. The jack should always be inspected to make sure it is in good working order with no damage. Jack stands are designed to support the weight of the vehicle; neither jack style is designed to support vehicle weight, only lift it.
Jack stands must have a rated capacity greater than the axle being lifted. If you are lifting an entire axle, then two jack stands are required, one on each end of the axle. Jack stands all must have a mechanical locking pin to prevent accidental vehicle lowering.
When it comes to lifting, one very common mistake is that the ground under the axle was not inspected to ensure it is firm and level prior to lifting the vehicle. If the ground is soft and/or uneven, then it is time to move the vehicle to a better location. You certainly don’t want the vehicle sinking into soft ground during this process.
Once you do find a suitable location, the vehicle must be secured using wheel chocks to ensure it cannot move forwards or backwards. The parking brakes also should be applied.
It also is very important to ensure the jacks and jack stands are placed directly under the axle beam/tube. Never place the jacks on the U-bolts, which can be damaged and make future spring replacement a lot more difficult. In addition, the area on the U-bolt is very small and placing a jack in this area could pose a safety hazard.
After the tire has been raised about an inch off the ground, a jack stand must be placed directly under the axle. Then, release the jack so the load is completely supported by the jack stands. Never crawl under or work on a vehicle unless it is supported by the jack stand.
Tire air pressure should be checked prior to removing the tire assembly from the vehicle with a calibrated gauge. If the measured tire pressure is 80% or less of the fleet pressure specification, then the tire must be completely deflated prior to removal from the vehicle.
An impact wrench can be used to loosen each wheel fastener. After the fasteners have been removed, the wheels should be removed carefully so as not to damage the threads on the studs.
Following the correct procedures when it comes to mounting, de-mounting and inflating tires both on and off a vehicle will ensure that everyone remains safe and free from injury.