SUQ 13 Daniel

Well today was the last day for me to work at the Bellingham School District bus garage. The overall experience was a good one. At times there was jobs I had to do that were not the most stimulating experience and some that were just routine mundane stuff. I made it a challenge for myself to stay alert and found things to find things to fix. I not talking about finding things to fix just to fix something, but something that could be a big problem down the road. I leaned and gained experience  on inspecting, routine maintenance, testing batteries, finding parasitic draws, changing tires, changing brake canisters, seat repair, taking out a automatic transmission, and driving buses. Also learned what kind of things would brake or the wear points on Thomas Build and Blue Bird buses.

Week Hours: 40
Hours To Date: 384

SPQ 13 Daniel

We are getting ready for the annual Stat Patrol inspections that is coming out soon. I'm not really doing anything new. Just the same thing over and over; changing oil, changing out filters, greasing, and doing the overall inspection. I haven't found big to do repairs on any of the buses. Witch is a good thing, but is nice to change things up a bitt.

Week Hours: 40
Hours To Date: 160

SPQ 23 Daniel

a continuation for last blog:

All the buses we have come in for at least an inspection and greasing every 2,000 miles. We will change oil and filters as the service interval comes up. Pretty much every inch of the bus is looked over for anything that is out not right. The inspection sheets have all the main things to look at by really you are looking at more than what is on the three pages. PMs are really when you have vehicle that is transporting other parents kids.

 The brake system is a really important part of a bus to keep maintained. Bad things could happen if the brakes fail while operating the bus. When preform my inspection of the bottom side of the bus, the brakes are one of the first things I look at. Things that I look for are, broken parts, missing parts, cracks, brake lining (needs to be more than 1/4in thick), wearing, grease or oil, and any other form of damage. I take a look at the brake chambers and the slack adjusters to make sure that they are not damaged and they are secure. Other things I look for as part of the brake system is, damaged hoses or lines, air leaks, damaged valves, and make sure there’s no damage to the air tanks.

I also check the push rod stroke. Here are the steps to check the push rod stroke: first, identify the brake chamber size. Second, look up the maximum allowed push rod length. Third, make a mark flash with the camber housing. Fourth, have someone apply the brakes. Fifth, measure from the face of the chamber to the mark that you made on the push rod.

 

SPQ13 Daniel

Preventive maintenance is very important to keep up on. It will help prevent costly down time and most importantly help prevent injuries deaths. PM should be performed on all vehicles or equipment. A PM program should be set up so that your vehicle or equipment is check on a regular basis. Things that should be in your PM program are (but limited to), checking or changing fluids, greasing, changing filters, inspecting for damage or worn parts, making sure things are saucier, look for leaks, ext.

The information to I provide for PM is for a 2011 Thomas Built SAF-T-Liner HDX school bus. It runs with a Cummins ISB 6.7L 260HP engine, 2010 Allison 3000PTS transmission (4^th gen controls with prognostics) and a Ege Endustri drive axle. The brake system uses Bendix and Haldex components. The front axle and suspension is DaimlerChrysler or Axle Alliance. It has both their names on it. At the back the bus has a Holland rear suspension. And Spicer wants a piece of the bus, the drive shaft and the steering shaft. So as you can see Thomas use a lot of other companies parts.

Part of the PM for this bus is changing out or checking the engine oil, transmission oil, and coolant. There is also a lot of greasing going on to.

Engine Oil and Filter

Engine oil is what keeps the whole engine lube and other components; like the air compressor and the turbo charger. If there is not enough oil in the system you will have metal to metal contact of moving parts. Temperatures will raise and part will seize and brake. Metal shavings will be made and will destroy bearings. Things get worse and go downhill fast. If you don’t change your oil at proper service intervals the life of your engine will shorten. Over time the oil brakes down and it also collects a lot of contaminates. Yes there is a filter but it doesn’t get everything. There is a chance for your filter to get clogged up. Then the oil is just bypasses the filter through the bypass valve and the oil is not filtered at all. So the moral of the store is change the oil and filter at recommended service intervals. To check the engine oil level, first park the bus on level ground. Second, turn off engine and let stand for a few minutes. This will allow the oil to return to the sump. Third, pull out dipstick and whip it off. Then stick it back into the dipstick tube. Pull out the dipstick one last time and check oil level. Add or drain oil as needed.

Engine oil we use is: 76 Guardol QLT 15W-40
http://www.phillips66lubricants.com/brands-products/Single.aspx?pid=14&brand=76+Lubricants
Filter: Baldwin – B7177
http://catalog.baldwinfilter.com/starttrucksbusesapps.html

Engine Oil Capacity

    pan only: 15qt

    total system: 17.6qt

    oil filter: 1qt

Engine Oil Dipstick

    low to high: 2qt

Oil Pressure

   low Idle (min allowed): 10psi

    at rated speed (min allowed): 30psi

    oil regulating valve opening pressure range: 65-75psi

Engine Oil Temperature

    maximum: 280 F

Service Intervals

    oil: 6,000 miles

    filter: every oil change

 

Transmission Oil and filters

The transmission oil stays cleaning than the engine oil because the soot from burning diesel contaminated oil and other factors. So you do have longer service intervals for the tranny oil and filters. None the less it is important to PMs for the tranny. If the oil is to low or to high then you will performance problems, like the tranny not shifting right. It could over heat with not enough oil. Filters can get clogged as well, making the oil to bypass without being filtered. Dirty oil will not properly lube the moving parts in the tranny. Checking the oil level in the tranny is similar to checking the engine oil level. The difference is you leave the engine running and you put the tranny in neutral (this may very between trannies). Then check the level of the oil. On the dipstick there will be cold and hot level markings. So if the oil is cool (61-120 F), use the cold level markings. If the oil is up to operating temp (160-200 F), use the hot level markings.

Transmission Oil we use: Phillips 66/Conoco/76 - Super ATF
http://www.phillips66lubricants.com/brands-products/Single.aspx?pid=185&brand=Phillips+66
Filter: Allison – 2954778

Oil Capacity (4in sump)

    initial fill: 29qt

    refill: 19qt

Service Intervals

    oil: 25,000 miles

    filter: 25,000 miles

 

Cooling System

Cooling system is really important for cooling down the engine and other components. If the cooling system is not maintained properly, things will over heat. The engine, air intake, EGR, engine oil, tranny oil, and sometimes the turbo and the air compressor, all relies on the cooling system. The coolant needs to be kept at the proper levels. To low you get over heating and too much you will have coolant squirting out. Coolant can freeze, so it should be tested to that it won’t freeze in the climate that you are in. The PH should be check as well. The coolant can start eating away the insides of your engine. You should check for oil in the coolant to make sure there is no internal leaks. You should check all the hose to make sure they aren’t cracking, leaking, or rubbing against anything.

Coolant we use: Chevron Del Extended Life 50/50 Coolant – B
https://cglapps.chevron.com/msdspds/MSDSPage.aspx?directMSDSLink=true&language=en&region=NA&rbSearchType=True&txtMSDSNumber=227811&lbLanguage=ENGLISH&lbCompany=UNITED%20STATES

https://cglapps.chevron.com/msdspds/PDSPage.aspx?directPDSLink=true&language=en&region=NA&txtPDSNumber=227811&lbLanguage=ENGLISH&lbCompany=UNITED%20STATES

 System Capacity

    about 19 gallons

Service Intervals

    Coolant: 750,000 miles

Freeze Point

    around -34 F

 

Chassis Grease

There are a lot of moving parts under the bus. There is steering, brake, suspension, and u-joints. Without this grease you would have part wearing out really fast. Some part would be squeaking and don’t want that. It is not that hard to grease up all the points and it doesn’t take that much time. Keep in mind when you grease that you don’t need to pump a lot of grease, just enough to where you can see or hear the new grease coming out. Make sure that grease is going in, if not replace the zerk. Also clean off the zerk before greasing.

Grease use: Phillips 66/Conoco/76 – Multiplex Red #2
http://www.phillips66lubricants.com/brands-products/Single.aspx?pid=200&brand=Phillips+66

Unlike the Freightliner on the lift at school witch had 43 zerks, the Thomas bus has 19 zerks.

This picture here is one of the trickier zerks to find on the Freightliner. It is up on the side of the transmission. There is on other one on the other side.

 

 

A tricky zerk to find on the Thomas bus is the one on the steenig shaft. When you pull in the wheel are pointed straight forword. At that point the zerk is on the other side and you can't see it. You have to trun the steering wheel to get to it.

 

 



 

Here is the inspection sheets that is follow for when a bus comes in its PM servcie interval.

SPQ 13 Daniel

So this blog is going to suck. I feel like I've been searching and reading a lot, but I just can't remember is. Maybe it's because I'm trying to focus on to much stuff at one time.


Week Hours (plus last weeks): 69
Hours To Date: 291

SPQ 13 Daniel

Hydraulic Cycle Times

Here is a video of the Bobcat Excavator's bucket curling both ways. The machine is at operating temperature, about 150 degrees. Also the engine is at high idle.

Here are the cycle times.

Bucket Dump: 1.25 sec               (manual spec: 1.9 sec)
Bucket Curl: 2.3 sec                    (manual spec: 2.7 sec)


Next is the travel speed. Again the machine is at operating temperature and the engine is at high idle. This Bobcat has two speeds; a low gear and a high gear. This next video will show how many revolutions the track will move in one minute. There is a piece of red tape on the track to show when one full revolution is completed. Also the length of the track is 173 inches.

Revolutions in 1st gear: 11rpm

This next video is the Bobcat is in 2nd gear.

Revolutions in 2sd gear: 18.25rpm

So here I did some math to take the RPM and turn it into MPH. Hopefully I did the math right.
 
1st gear

11rpm x 173" = 1903 in/min
1903in/min / 12" = 158.583ft/min
158.583ft/min x 60min = 9514.98ft/hr
9514.98ft/hr / 5280' = 1.8mph


2nd gear

18.25rpm x 173" = 3157.25in/min
3157.25in/min / 12" = 263.104ft/min
263.104ft/min x 60min = 15786.24ft/hr
15786.24ft/hr / 5280' = 2.99mph

The outcome speed of the tract:

1st gear: 1.8mph              (manual spec: 1.6mph)
2nd gear: 2.99mph          (manual spec: 2.9mph)




Here is the procedures for when a new hydraulic pump is installed in a machine. This will prevent a dry start up of the hydraulic pump.

 

·         Loosen the case plug until all the air is purged from the pump housing.

·         You will need to crank the engine without starting it. To do so use a bypass tool that can be hooked to the starter solenoid battery terminal and S terminal.

·         Crank the engine for 15 seconds, then stop for at least 30 seconds. Again, crank the engine for 15 seconds.

·         Disconnect the bypass tool.

·         Start the excavator from the operator cab and run the engine at low idle for 1 - 2 minutes without operating the hydraulics.

·         After operating the engine at low idle, operate the hydraulic systems several times or until air is purged from the system. Avoid running over the relief valve setting at the end of cylinder stroke.

·         With the excavator parked on a level surface, check and fill the hydraulic reservoir as required. Check for hydraulic leaks.

So it was asked, "Is it was possible to complete the testing, give in the bobcat manual, with the 30gpm flow meter that was us on the winch and windlass?"

My answer would be, yes. We would be able to do it, but you will be pushing the limits of the gauge. The problem is that the pressure gauge that's hooked with the flow meter goes only up to 3500psi. In the manual, they have you set the main relief valve at 3550 + or - 75psi. So with that window of 150psi you could get away with setting the main relief valve as low as 3475psi. Again that you are getting close to the limits of the gauge.

Taking a hydraulic schematic and coloring the line a circuit helps a lot in knowing how it works. Also it will help with finding out what is wrong. With a little research I could find all about each component and what there function is. This helps with simplifying things and help you focus on what you really need.

Week Hours: 33
Hours To Date: 222