6/15-6/20 King Pin, Alignments,

This last week we learned how to properly remove a king pin. Cody and I removed the pin from the red Freightliner in the shop. Instead of bushings it had pin bearings, the argument was that these would last longer than bushings and withstand more heat and abuse than normal bushings. I learned a lot from this process, I feel confident that I will be able to remove a king pin in the future much more quickly than this time around. When we re-installed the king pin we torqued the locking pins to 30ft-lbs, replaced the caps, and finally placed the retaining rings back into place.  

King Pin

Removing the locking pins via a brass drift 

Torquing the locking pins

Alignment Pictures

via laser

Via tape measure

Adjustment

BTC Hours: 16

Total Hours: 337.5

6/8-6/12 Clutch adjustments

This past week we were shown how to properly adjust a clutch. There are two methods common to adjusting a clutch:
Removing the lockstrap and adjusting the adjusting ring with the proper tool
Using the Kwik-Adjust mechanism
The Kwik-Adjust is becoming more common and is much easier to service.
Some clutches are self adjusting and only require visual inspection of the wear indicator found on the cover.

(Pictures Will Be Added As Soon As I Get Them From Classmate)

Now, this is all fine and dandy, however, I am a visual person and have always had trouble figuring out how a clutch even WORKED. I got the concept, I just could not picture it for the life of me. Luckily, a nice person on YouTube decided to create and animation showing how a clutch worked in great detail. I would highly advise taking a look. He also has many other helpful animation videos explaining other features such as how does an automatic transmission work.

https://youtu.be/pqF-aBtTBnY


BTC hours: 20
Total: 321.5 hrs

June 1-5 Air brake relay

Learning about air brake relays last week got me wondering what one looked like inside. I am a visual learner and could not picture what the text was talking about in regards to how it worked. So naturally, I set out to take one apart so that I could see the inside of it!

The relay valve is used to speed the application and release of the brakes. It gives the same amount of air pressure to the brake chambers as it receives from the foot valve or other source.

BTC hours: 10
Total: 301.5

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