Tank to pump supply line/Stitch welding (6/6-6/10)

A truck came in with complaints of a leak somewhere in the pump housing. We found the leak on the threads of the tank to pump pipe line at the check valve. To remove the section of pipe I unbolted the a flange that housed the tank to pump butterfly valve and on the tank side I had to loosen the clamps on the rubber boot that joins the tank to the pipe. After I got it out of the truck I managed to get the pipe to off of the check valve to find the threads had a decent size crack in them due to rust build up in the pipe. We then cut off the bad threads and cleaned up the pipe and were able to weld a new threaded end onto the pipe so that we would keep the pipe the same length needed. My co-worker informed me that since we were welding pipe we would have to use a stitch weld method. A stitch weld on a pipe requires you to weld uphill in small sections and allowing the metal to cool slightly between welds so that the material does not overheat compromise the integrity of the pipe. The purpose of welding uphill is that it actually has deeper weld penetration and is much stronger than welding downhill. But caution must be taken to not overheat the pipe so that your puddle runs back downhill. So welding in small sections allowing it to cool in between for a moment prevents defective welds. After this is complete the weld must be check. we cap off both ends of the pipe and attach a regulator with shop air to charge the pipe with approximately 20-30psi shop air check the weld with soapy water. Caution must be taken to not overcharge the pipe, because charging a 4' section of 4" pipe with any more than 30psi can be extremely dangerous. ALWAYS use a regulator and make sure that both caps are SECURE. 

Pipe line removed (Pump side of the flange) 

Sometimes, you just need 4' of leverage

Capped and ready for air

Stitch welding done by my coworker 

Regulator attached and shop air 

Hours: 40

Running Total: 362

Custom Tool Box Table (5/30-6/3)

We had a slow day at the shop and I asked if I could use some scrap aluminum to make a table for my tool box. My shop lead was fine with it so that I could get more practice with aluminum welding. After making the measurements my lead gave me some advice to set the support arms that were going to be welded on an eighth of an inch smaller than my measurement to compensate for the welder pulling the metal. Seeing as my box is too thin to tap for bolts I got to learn how to use a thread insert gun to use mounting bolts. Fun little project and got to practice aluminum welding. 



Hours: 40
Running Total: 342

Tank Removal/Valve Rebuild (5/23-5/27)

We serviced a truck this week that had a unique issue. The truck had a 750 gallon tank with a foam cell that contained 100 gallons of foam concentrate. The truck was found to be overweight by the area standards where the customer had the truck in service. They requested a new tank to be created at the factory that held 250 gallons of water less to meet the weight limit. I was able to help removed the old tank. This process included completely disconnecting the pump housing from the tank as well as fabricating a custom welded hoist to remove the tank. Cool project.





Our massive drill press with a 1 1/4" drill bit...
 


I also got the opportunity to rebuild leaking discharge valves on a truck that came in for service. To diagnose this we charged the pump with shop air and discovered a few leaks including the #2 discharge valve on the pump. Over time the ball valve in the valve housing wears down from debris in the water scoring it in addition to hard water breaking down the seals. It's a pretty easy but fun process of removing the valve to rebuild it, a very satisfying end result I might add.

Hours: 40
Running Total: 302

Poly Welding (5/16-5/20)

Couple of cool projects that week. I had the opportunity to an old aerial truck. It is a 75' ladder than extends by means of a series pulleys with steel cables all being pulled by a hydraulic motor. A section of the the ladder had some steel cable that was beginning to fray and needed to be replaced. In order to access the cable the ladder was fully extended down the length of the shop and supported by a stand at the end of ladder in case the trucks hydraulic stands failed.




We had a slow day that week and my shop lead to advantage of the time to train me to plastic weld. A lot of the trucks we service have poly plastic tanks and will require repair from time to time. As with all welding surface preparation is key, the surface must be buffed out an clean as possible. The equipment is essentially a glue gun on steroids. After the gun pre-heats a rod is inserted in the tip of the gun and with steady pressure and speed a pass is made along the two pieces of poly plastic are joined together. Pretty straight forward process.

Hours: 40
Running Total: 262

Week 6 (5/9-5/13) Pump Overhaul

Started my new job and first day found myself helping the shop lead remove and rebuild a pump out of a truck. The pump was leaking according to the operator. Upon removal of the outboard bearing cap housing we found water had made it past the seal and ruined the bearing on the discharge side. The pump relies on packing to seal water inside the pump rather than a mechanical seal. The problem was that the packing inside of the stuffing box had overheated and become a solid black mass allowing water to seep by. We replaced the stuffing box and installed new gaskets and o-rings.

The advantages to using packing vs a mechanical seal is that packing is more user friendly and are more robust against hard use. Mechanical seals a very sensitive and can be damaged very easily while installing them in addition to being more at risk to wear and tear by untrained operators.

Fire Truck! 

Pump Compartment (Half of pump removed)

Stuffing Box

Hours: 30
Running Total: 222

Week 5 (5/2-5/6) Hydraulic Steering

We have a piece of equipment with hydraulic steering. The operators are complaining that there is a delay in the steering followed by a suddenly turning sharply. After pulling it into the shop we found that there was indeed a delay in the steering but not sharp grab. We attached our pressure gauge and found the system to be operating within manufactures specs for pressure. The filters have been changed recently and the system is not contaminated as far as my co worker and I can see. Would this delay be due to the directional valve in the steering wearing out over time? The equipment is almost 30 years old.

Hours: 40

Running Total: 192

Week 4 (4/25-29) Cold Start System

We noticed a piece of equipment having a difficult time starting for the operators in the morning. We pulled it in the shop to check the starting system. We started with the glow plugs. I placed my meter on the glow plug railing and found a good ground. I found that I got no voltage to the railing. So I placed the meter on the first plug in the circuit, nothing. I then Attached my meter to the supply wire for the plugs and found a healthy 12.7V. I pulled the first glow plug in the circuit and switched my meter to ohms and found that it read a healthy OL on the screen. A new set of glow plugs later and it starts beautifully every time.

Hours: 40
Running Total: 152

Exhibit A

Problem Child

Railing 

Week 3 (4/18-4/22) Headlight/Belt

While checking one of the pieces of equipment I found that one of the headlights was out. So, naturally, I figured the bulb was bad. I opened the housing and tested the post that connects to the jumper wire that feeds the bulb and found 12v. Bulbs bad! After installing a new bulb I was disappointed to find that it was still out. Bulb was good... I figured out fairly quickly after that with some closer investigation that the jumper wire was completely corroded inside as I did not have 12v coming out the other end of the wire. So after kicking myself in the butt and listening to my coworker make fun of me for a minute or two, I replaced the jumper wire and now the bulb works just fine. Lesson learned, go to the LOAD and work your way back.

Also got to replace some belts on the push back, not too exciting but it's fun to work on and thought I'd post some pics.



Hours: 40
Running Total: 112

Week 2 (4/11-4/15) Water Pump

One of the the Tugs was having an issue with the water pump fan mounts coming loose. We were able to remove the fan and confirm that no damage had been done to the equipment. While reinstalling the fan we torqued the fan into place and applied a dab of Lock Tight to ensure that it would not bring itself loose again.

 

Hours: 40
Running Total: 72

Week 1 (4/5-4/8) Power Steering Flush

Nothing too exciting for the first week of the quarter at work. We flushed the power steering on one of our fueling trucks. The process was pretty straight forward. We placed the front axle on jack stands so that the front wheels hovered a few inches above the ground. We detached the return hose on the bottom of the filter housing and exercised the steering wheel from full left to full right until the fluid had been completely drained from the system. We installed the new filter and filled the system with fluid while exercising the steering wheel to eliminate air bubbles in the system.

Hours: 32
Running Total: 32

Week 12 (3/21-3/25) Pressure Relief Valve Testing

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A very important feature of the fueling trucks is the ability to relieve pressure while the pump is running and the fuel has no where to go. The primary pressure relief valve is set to relieve pressure at 40psi. If this valve fails a secondary pressure relief valve will kick open at 50psi. These valves have to be tested and adjusted. We use a calibrated pressure gauge on the fueling nozzle to ensure that the pump panel is accurate and the relief valve opens at the appropriate pressure. The pump panel gauge is allowed 3psi difference from the calibrated gauge. These pressure gauges on the panel get the readings from venturis located on the fueling pipes after the pump and can be adjusted to match the calibrated gauge. After the primary pressure relief passes a bypass valve is turned to test the secondary relief system. Kind of a neat process to test the trucks.


(Left) Calibrated gauge hooked up to the nozzle on the "recirc" port on the tank.

(Right) The nozzle is then closed to 95% position and 40psi is achieved as the primary releases. If the primary is <40 or >37 it must be adjusted.










 (Far Left) Bypass valve
(Above) Venturi with adjustable fitting so that gauge at panel can be calibrated.

Hours: 40
Total for Winter 2016 Quarter: 460

Week 11 (3/14-3/18) Fuel Storage Water Defense Testing

We have an offsite fuel storage facility for our company that we refer to as the "fuel farm". The farm requires various testing on a monthly, quarterly, semi-annual, and annual basis. This particular week we performed quarterly checks at the farm. Part of this test is to ensure that the water defense is functioning properly. On an annual check we would plumb in a hand pump and pump water into the filter vessel (which has a VERY expensive fuel/water filter on the outgoing port preventing the water from escaping into the rest of the system) until the water level in the sump of the filter housing reaches the water sensor and shuts down the entire farm resulting in a doomsday alarm sounding until we reset the system and drain out the contaminated fuel in the filter housing. Luckily, this being a quarterly check, we only had to test the sensor using the test port on the side of the sump which houses the water sensor. This sensor can be isolated from the rest of the pump system while it is running. We then add a small amount off water to the sensor housing until the alarm sounds and we confirm it is in working condition. Once you learn all of the pump components it becomes very easy to operate this system. 

 Hours: 40
Running Total: 420

Week 10 (3/7-3/11) Starter Replacement

Nothing too exciting this week. We had a starter going our on one of the fueling trucks. This is a 2006 International 4200. The truck was beginning to have trouble starting in the morning. My first thought was there was a parasitic draw on the batteries throughout the night. However, the truck began to have the issue throughout the day even after running for over an hour. I started by grabbing the trusty multi-meter and performed a starting-charging system test. The batteries had adequate voltage (12.9) and dropped to a mere 10.1 upon starting. The alternator was returning an acceptable 14+ volts to the batteries (unfortunately I did not have an amp clamp handy to check amperage). After removing the starter we took it to Romaine Electric in town who confirmed our suspicion. The trucks start 10-15 times per day, it's a rough life for them out at the airport.



Hours: 20
Running Total: 380

Week 9 (2/29-3/4) Brake Drum

Got an email this particular week that a beltloader was "not moving forward." Took off the rear end to find that on one side the brake shoes had... well, exploded. There was chunks of pad inside of the drum. Luckily, my partner has a great deal of experience with finding on miscellaneous equipment and identified the brake rear end off of a 70's era Ford F250. After some patience at Napa and careful measuring we were able to install the correct shoes (in the proper position this time mind you, as whoever had done the previous brake job installed them incorrectly). Problem solved, pretty easy week.

 
Hours: 40
Running Total: 360