2/16-2/20 Leaf Spring Replacement & Bearing Inspection

I spent the majority of this week working on the shop truck to replace the front leaf springs. The process was very straight forward, or at least it sounded straight forward before I got into it. I learned through trial and error, that the easiest way is to lift the vehicle is by the frame, support the front axle, detach the front shocks, then remove the shackle bolts and u-bolts to release the leaf springs as well as the front axle. The new leaf springs proved to be difficult to install. A few modifications had to be made so that the new springs would fit. In addition to getting new leaf springs the truck was also getting new rotors and having the bearings cleaned/inspected and repacked. I learned that in order to properly check the condition of the bearings they must be thoroughly cleaned before inspection. Each roller is inspected for damage as well as the racers. This can be achieved by shining a light through the back of the bearing to assist in checking for wear defects.

All in all this project was a great learning process for me. The mechanics at NWFR gave me the freedom to tackle this leaf spring project virtually on my own while they caught up on more time sensitive projects. They did make themselves available to answer any of my questions and made sure to check on me every once in awhile to ensure I doing alright. By the time I finally finished the leaf springs John was able to teach me about bearing inspection. I gained a lot of knowledge this week.

I neglected to take more pictures of the wheel bearings during the inspection process, it's hard to remember to take out your phone in the middle of a project to take a picture for a blog. 

Removing the u-bolts

Out with the old

As you can see the pin is larger on the new springs

This proved to be my greatest frustration, as drilling out the new hole to accommodate this larger pin proved to be quite the head ache.  

2/9-2/13 Electrolysis

We had one of the departments tenders in the shop last week for its annual maintenance. Part of the the maintenance procedure was a voltage test. While checking the battery voltage and output, we also checked the engine coolant for stray voltage. Curious as to how voltage could end up in the coolant, I asked how this could occur. I was told that an improperly connected ground wire could cause a short as the electrical charge tries to find the path of least resistance to a ground source. When this happens, the current degrades metals, often in the radiator, in a process known as electrolysis. This process does not take long at all, compared to corrosion which may take months to do damage, electrolysis may only take days to weeks for irreversible damage to occur.

Unfortunately, my phone does not want to upload the pictures of the sample cylinder sleeves that our instructor, Jeff, had on display for us. So I will upload the next best thing; google images!

 


Total Shop Hours @ NWFR for Feb.: 44.75
Total Shop Hours @ BTC for Feb.: 28

1/26-1/30 Cutting Torches

This last week we learned a valuable skill, using an acetylene torch for cutting 3/8th steel. This was part of our wrench assignment. Using nothing but a cutting torch, hacksaw, and files, we were instructed to craft a 2" wrench with an allowance of .014th of an inch. The acetylene for the torch must be properly mixed with oxygen for an effective cut. We were provided with sources to find what tip we needed for the torch as well as the fuel to oxygen mixture for the 3/8th steel we would be cutting.

Cutting 3/8th steel with a 0 size head with the O2 at 25/30 and gas at 3/5

Radiator Replacement (1/29-1/23)

Highlight of this week was probably the removal of a radiator out of NWFD's '87 Chevy suburban. It's a back up rig, very rarely used so it sits unused for long periods of time. While conducting its annual inspection and maintenance, my supervisor and I noticed a great deal of coolant on the front of the engine block. We concluded that the radiator had finally gone south on the ol' girl and needed replacing. Due to a new exhaust system going in at one of the other stations in the district, I was left unsupervised in the shop to complete the tune up and radiator replacement on the suburban. Fortunately, the shop is still standing. I learned the basics about removing and then re-installing a radiator, it was a lot easier than I expected it to be.

Old radiator

 I also replaced the inner tie rod, adjusting sleeve and outer tie rod. This required me to learn how to properly adjust this entire assembly. After many failed attempts and test drives, I finaly managed to get it right.

Hours: 20

Total: 56

Assignment #2 - Breaking the Bucket of Bolts

  We were given four types of bolts, and instructed to break them. Me and my classmate torqued each bolt and recorded the strain on the bolts in pounds when the bolt was torqued to its specified torque. We then continued past the set torque to find how much the bolt could take before breaking, and recorded the max torque and tensile strength in pounds. This assignment gave me valuable knowledge, not only that different grades of bolts and their different strengths, but also, what it feels like when you've gone to far and broken a bolt. We also placed the bolts in a "bolt stretcher" for lack of a better description. It would display the amount of stretch in pounds that were acting on the bolt.

Specs for types of bolts

The Grade 5 actually stripped the threads instead of snapping

3907 bolt

Grade 8

All three after the carnage

Preventative Maintenance and Small Engines (1/12-1/16)

     This last week I have had a wide variety of experience at the shop. For starters, we had an engine come in that was due for it's annual maintenance. This service ensures the proper function of each component; from the apparatus pump system performance to the functionality of a seat buckle, nothing is overlooked. This particular PM that was completed also included a coolant flush. The radiator was first drained into a holding tank, flushed with clean water, then refilled with the appropriate amount of antifreeze.

   I was given the task of performing the annual maintenance of the lawn tools used at on of the staffed stations. I now had a weed eater, leaf blower, and lawn mower placed in my charge. The weed eater and lawn mower were simple enough. I replaced the spark plug, drained the old full mixture, cleaned the air filter, sharpened the blade on the lawn mower, and re-wrapped the string that was put in backwards on the weed eater.

  The leaf blower needed the pull cord replaced, and after struggling with a spring that just did not want to stay put, I managed to get it all back together. Of course, I did loose a VERY small washer which just so happened to be VERY important the the workings of the pull cord assembly. Needless to say, from now on, a magnetic tray will be used when dealing with small components.

Shop Hours: 16
BTC Hours: 14

Day 1 - Bucket of Bolts

Yesterday, my classmate and I worked diligently to complete an assignment given to us by our instructor, Jeff Curtis. The assignment was to identify 4 bags of miscellaneous nuts, bolts, studs, screws, etc. We were to give a brief description of each piece in addition to its size, thread pitch, material, finish, and wrench size. With this information we were to find a part number which would be used to reorder the piece through McMaster - Carr's website.

This exercise familiarized us with a wide range of fasteners and gave us the knowledge and tools to identify them.

Class time 0800-1415
01/12/2015