Clean and check wheel bolt connection components, then protect against corrosion - AP40.10-P-4050-01A

Before mounting a wheel-and-tire assembly all  the following operation steps must be carefully conducted. Otherwise the wheel-and-tire assembly may work its way loose from the vehicle and cause damage to people, property or the environment!

Clean 

1. Remove lubricants and soiling such as, e.g. oil, grease and sand from the following components:
   • Contact surfaces, joints and centering on disk wheel, wheel hub or wheel flange and brake disk or brake drum,

     Remove corrosion products using wire brush or emery cloth.

   • Channel or spherical caps on disk wheel,
   • Thread and channel or spherical caps of wheel bolts or wheel nuts,
   • Thread for wheel bolts in wheel hub or wheel flange or
   • wheel stud threads.

   Remove corrosion products using wire brush or tap.

   Contaminated threads must be cleaned. Remove all corrosion and dirt from corroded threads using tap. There must be no chip-removing material erosion. Otherwise the wheel-and-tire assembly may work its way loose from the vehicle and cause damage to people, property or the environment! Any dirt left in the thread prevents the wheel bolt or wheel nut from reaching the necessary preload force, despite the nominal torque having been reached.

   Fig 1: Identifying Cleaned And Uncleaned Surfaces Of Wheel And Tire Assembly

   Courtesy of MERCEDES-BENZ USA
   Fig 2: Identifying Wheel And Tire Assembly Contact Surfaces Soiled With Grease

   Courtesy of MERCEDES-BENZ USA
   Fig 3: Identifying Cleaned Contact Surface Of Wheel And Tire Assembly

   Courtesy of MERCEDES-BENZ USA

   Left half of picture: 

   Right half of picture: 

   Inspecting 

2. Check the following components for damage:
   • Contact surfaces, joints and centering on disk wheel, wheel hub or wheel flange and brake disk or brake drum,
   • Channel or spherical caps and rim flanges on disk wheel,
   • Thread and channel or spherical caps of wheel bolts or wheel nuts,
   • Thread for wheel bolts in wheel hub or wheel flange or
   • wheel stud threads.

   Replace wheel bolt, wheel nut or wheel flange if thread is damaged.

   Replace disk wheel, wheel flange, brake disk or brake drum if damaged. Otherwise the wheel-and-tire assembly may work its way loose from the vehicle and cause damage to people, property or the environment!

   Left illustration 

   Fig 4: Identifying Wheel And Tire Assembly Contact Surfaces With Corrosion Products

   Courtesy of MERCEDES-BENZ USA

   Right figure 

   Fig 5: Identifying Clean Contact Surfaces Of Wheel And Tire Assembly

   Courtesy of MERCEDES-BENZ USA

   Left illustration 

   Fig 6: Identifying Spherical Cap With Seizing Marks

   Courtesy of MERCEDES-BENZ USA

   Right figure 

   Fig 7: Identifying Spherical Cap With Even Contact Pattern

   Courtesy of MERCEDES-BENZ USA
3. Check channel or spherical caps of wheel bolts, wheel nuts and disk wheels for signs of damage, seizing marks and material deposition.

   Replace wheel bolts, wheel nut and disk wheels that are damaged or show signs of seizing marks or material deposition. Otherwise the wheel-and-tire assembly may work its way loose from the vehicle and cause damage to people, property or the environment! Remaining seizing marks or material deposition prevents the required preload force of the wheel bolts or wheel nuts from being reached, despite the specified torque having been reached!

4. Check disk wheels for deformation.

   Replace deformed disk wheels subject to separate repair order.

   Apply corrosion protection. 

5. Apply a thin coating of long-life grease as corrosion protection to the marked area of the center hole guide (arrow) on the wheel hub or wheel flange and wheel contact surface.

   Do not apply grease or other lubricants to threads of wheel bolts, wheel nuts, wheel hubs, wheel flanges or wheel studs. Otherwise the wheel-and-tire assembly may work its way loose from the vehicle and cause damage to people, property or the environment!

   Fig 8: Locating Grease Applying Area Of Center Hole Guide On Wheel Hub

   Courtesy of MERCEDES-BENZ USA