Month of May. Wheel ends and brakes.

  Here we are at the end of May. Where did the time go? Best catch up what I have learned and done.

  We began to learn the basics of performing wheel end maintenance. Complete dis-assembly started with removal of the wheels and tires (obviously), brake drum, hub, bearings,  seals, s-cam, automatic slack adjusters.

  Inspection during this process is key. Even minor details can give you insight to deeper problems that may be easily missed. Uneven wear on the tires, for example, can indicate not only a misalignment, but worn bearings that need to be replaced. The drum is inspected for odd wear as well, measurements are taken of the interior to ensure it is still in specification.

  Typically I will remove the brakes next and inspect them to insure that they are wearing evenly and are not worn past the specified wear indication mark. We used several specialty spring removal tools, however, one tool in particular I found to be the most useful (pictured to the left). The rollers were also removed and cleaned.

 

  Next, hub and bearings are removed.


  S-cam removed and measured. I ended up replacing the bushings on a few wheel ends as I had more than 5 thousandths of an inch play in the S-cam.



Bearing were removed and cleaned, it is important to note that bearings should NEVER be allowed to sit with no kind of protective oil/lubricant because they will rust. Inner and outer race is to be visually inspected. I also replaced the hub seal on multiple wheel ends. There are two types that we used in class. Hand pressed and seals that require a drive. Hand pressed need to have a light coating of wheel end lubricant on them before installation.



When all said and done and the wheel end is being re-assembled the wheel end must have .001"-.005" free play. This is accomplished by torquing the wheel end nut to proper torque specs. The procedure usually has you torque to aprox. 200 ft.lbs while rotating the hub assembly, backing off a full turn, torque again to 50ft.lbs while rotating, then backing off aprox. a 1/4 turn. In the end you should have between .001"-.005." of free play.

Re-installing the wheels is pretty straight forward. Lugs for the trucks I was working on ranged in torque ratings from 450-500ft.lbs.

This concludes the month of may and my wheel end assignment.

BTC hours for 5/11-5/29: 45hrs.
Total hours: 291.5