3403 Sampling Requirements and Techniques
a Sampling Requirements Marine Corps Technical Instruction TI-4731-14 provides a list of all equipment and components of equipment that are to participate in the Joint Oil Analysis Program Currently all engines and transmissions for 5 ton tactical vehicles and the LVS front power unit are included in the progran
Sampling is conducted every 90 days or when a special sample is required; table 3-2 tells you when special samples are required All samples that are submitted as special samples must be marked
"special" with the reason for the submission indicated
Table 3-2 Circumstances Requiring a Special Oil Sample
Obtain a special sample WHEN
e the laboratory requests a special sample e there is indication of internal damage to the
engine or transmission due to an oil related failure ® your maintenance supervisor tells you to change the oil @® you have performed oil services due to changes in environmental conditions ® you have done an oil change BEFORE ws scheduled services
m performing maintenance on the engine or transmission (This includes the repair, replace- ment or installation of any oil lubricating part or assembly.) = removing the engine or trans-
mission, (regardless of the reason)
m= anticipated abnormally severe operating conditions
Trang 2As you can see, this covers just about all occasions The bottom line is to use the program and know what components need
sampling
Now, what publication lists all the equipment that participate in
the JOAP?
If you said TI-4731-14/1, you're correct This publication also provides detailed instruction on sampling methods and the overall Joint Oil Analysis Program
b Sampling Techniques
There are two methods used to obtain oil samples the oil sampling pump (fig 3-31) and the sampling valve method (fig 3-32) | of, AC | Ñ#=< ` Opec” a CAD `“ Vy, Fig 3-31 Oil sampling pump
Fig 3-32 Oil sampling valve
The sampling valve method is best It takes less time, is much easier to use, and provides a cleaner sample of a component's oil
Trang 3Lesson Summary In this lesson you listed the benefits of the oil analysis program, identified the publication used to
determine the equipment to be sampled, and identified the two methods used to obtain the samples In the next lesson you will
find out how to inspect and test lubrication systems
Exercise: Complete items 1 through 3 by performing the action
Lesson 5
required Check your responses against those listed at the end of this study unit
What are the three benefits achieved from using the Joint Oil Analysis Program as a part of your preventive maintenance program? a b C
What publication provides a list of equipment and components that require oil sampling? List the two methods used to obtain oil samples INSPECTING AND TESTING THE LUBRICATION SYSTEM LEARNING OBJECTIVES 1 2
Given statements describing leaks, identify in writing the classification for each leak
Given a situation where an operator reports a leak to you, the mechanic, state in writing the action required List the parts or areas where oil leaks are most likely to occur
Trang 45 State in writing the publication that provides procedures for testing for low oil pressure at the organizational level
6 State in writing the fault that could very easily cause enough excessive pressure to build up within a
transmission to cause seals and gaskets to start leaking 7 Select the procedure for testing the operation of the
transfer case oil pump on the LVS |
8 State in writing procedures for testing the number 1 and number 3 axle assemblies on the LVS
In lesson 4, oil analysis was described as a preventive
maintenance practice used to test the oil for contamination and wear metal particles Even with oil analysis, other maintenance
inspections and tests are still required If you use the JOAP in conjunction with the preventive maintenance inspections and
testing procedures covered in this lesson, you can prevent many serious problems
3501 Lubrication System Inspection
Other than contamination, the lubrication system's number one enemy is a leak Even though the oil analysis helps identify contamination problems, when it comes to a leak, you're on your
own |
Trang 5For example, a leak of one
Grop per minute would not be a major problem on the hydraulic reservoir of the LVS The reservoir (fig 3-33) has a capacity of 96 qts! So it's very unlikely that enough oil would ever leak out at that rate to cause serious damage
On the other hand, if the air shift unit (fig 3-34), which holds only a very small amount of oil, had a leak of one drop a minute, it would be
completely dry in a very short time
Trang 6There are three classifications of leaks:
e Class I Leakage of fluid indicated by wetness or discoloration but not great enough to form drops
e Class II Leakage of enough fluid to form drops, but not enough to cause drops that fall from the part being
checked or inspected
e Class III Leakage of enough fluid to form drops that fall from the part being checked or inspected
As a general rule, operation of the equipment is allowable with Class I or II lubricant leakage For safety reasons, brake fluid is an exception to this rule; you must repair or replace any
component(s) that are leaking brake fluid
Class III leaks, when found by an operator, will be reported to you, the organizational mechanic It is your job to determine how severe the leaks are (verify the classification), and
determine if the equipment can be safely operated Class III leaks are cause for deadlining
b Component leakage Leakage can occur almost anywhere
However, some areas or parts are more prone to leaks than others Gaskets, hose connections, plugs and fittings, and seals are where leaks are most likely to occur You may have to search to
find the true source of leaks For example, a leaking engine oil pan gasket may cause the transmission or other components to
appear to be leaking but the leak could be due to oil being blown over other components when the vehicle is moving You should clean components thoroughly and then operate the equipment while looking for signs of fresh oil
(1) Gaskets Gasket leaks normally occur because the
material has dried out or cracked Leaks will also occur around gaskets because of surface damage to components or loose mounting bolts This is especially true for
components like oil pans and valve covers Once a leak starts, it's hard to regain a good seal without replacing
the gasket |
Oil filters are frequently over-tightened, destroying the filter gasket Applying a little oil to the filter
gasket will help provide a seal Then be sure to torque filters in accordance with specifications
(2) Hose connections Loose or over-tightened hose clamps commonly cause leaks
Trang 7(4)
Drain plugs on the housings of most components have copper gaskets designed to be used only once These gaskets are often overlooked when changing oil and may leak Fittings often become loose and are a prime source of leaks Teflon tape or pipe sealer will help provide a seal and prevent them from working loose
Seals Most seals will show signs of moisture around sealing surfaces but this does not mean the seal is
leaking Seals require lubrication to prevent premature wear of the sealing material Seals without this
moisture will dry out and develop leaks Dirt and rust are a seal's worst enemies; they act as an abrasive which can destroy seals You must replace damaged seals
The following vehicle components often leak
Oil fill plugs Oil filter
Valve cover gaskets Output shaft seals Sending units
Wheel seals Flange gaskets
Front seals (engine) Oil pan gaskets
Oil drain plugs Oil coolers
Input shaft seals Rear main seals Hydraulic hoses and fittings Differential cover gaskets
Before we go on, let's see how much you're learning What action must a mechanic take when an operator reports a class III leak?
Trang 8
Now that we have completed the serious business, let's have some real fun working a word search puzzle Your task is to locate the names of the parts/components that often leak As a hint, there is no spacing between words: for example, valve cover gasket will appear as valvecovergasket | MIS TWHAY CHW AxKX OX KO SHANA se AAVALVECOVERGASKETI WCIMDSSGULPNIARDLIO YDRAULICHOSENJGQODL IYEYHWDAFRONTSEALVB MOAROVICLQYGUFKLRMK QJRFOUFOILPANGASKET OYMLGRFRTINUGNIDNES UVAACBEMRKMBWTWSMGB TAINNVRXEXLARLXPQDF PXNGTWEBVUOILFILTER ULSEVINPUTSEALBKUPX TAEGRQTVEKKAGQNJPTV SEAABKIEFGSWHNQCFFJ ESLSPUALJTTNMKHAYMNQ0 ALEKRHLBOILFILLPLUG LENETRCOKJHUHNSVAYW SENTJRORVDKAUUCBOSO OHYQRCVNXOILCOOLERF BWHNCSEEQSCNHRQUUJH GSDYBARQQMMAPWSMQMY
The answer to the first question is:
You should verify the classification of the leak
The definitions for the three classes of leaks are: Class I
Class II
Class III
Leakage indicated by wetness or discoloration but not great enough to cause drops
Leakage of enough fluid to form drops, but not enough to cause drops that fall from the part being checked or inspected
Trang 9The four most common parts or areas that leak are:
° gaskets e hose connections
e fittings and plugs e seals The solution to the puzzle is: -VALVECOVERGASKET- - GULPNIARDLIO HYDRAULICHOSE - -~ E -D-FRONTSEAL “ee Ree & Treew8weweee ke & =- ~ -RF FOILPANGASKET -O-ML F-TINUGNIDNES ~-U-AA E * -" - -T-IN R - -P-NG E -OILFILTER -ULSE-INPUTSEAL - ~-TAEG T + - -SEAA I -+ - -ESLS A - -AL-K L-OILFILLPLUG -LE-E C - E-T 0 - H V OILCOOLER- ~-W E-+ - ~~ eo we = = = wow a
If you had a difficult time answering any of these questions review paragraph 3501 before continuing with the lesson If the puzzle gave you a tough time, take another look You're not
losing your mind! Some of the answers are written right to left or bottom to top, but all fifteen components listed in the box on page 3-51 are included
3502 Inspecting and Testing the Engine Lubrication System The two conditions that should cause you to inspect and/or test the engine lubrication system are low oil pressure or high oil consumption To locate the problem, you should first perform the inspection If you still can't locate the problem, you will need to test the engine The one piece of test equipment that you have in the motor pool to test for low oil pressure or high oil consumption is the STE/ICE Use it to locate the fault You'll find the test procedures for organizational maintenance in the technical manual (TM-20 series) for the equipment being tested Let's now look at some of the possible reasons for low oil
- pressure or high oil consumption
Trang 10a Low oil pressure There are several reasons for low oil
pressure It could be caused by something as simple as a low oil level or something as complex as worn main bearings Table 3-3 starts with the most common causes of low oil pressure and the easiest inspection procedures and works up to the most complex causes and procedures for diagnosing then
Table 3-3 Procedures for Diagnosing Low Oil Pressure Problem To confirm the problem, inspect or check Low oil level Diluted oil Oil pan structural damage Inoperative oil pressure gauge Inoperative oil pressure sending unit Lubrication system failure
components for external leaks coolant for the presence of oil
engine for excess blowby oil for possible fuel contamination
oil pan for dents that may interfere with oil pump operation
oil pressure gauge reading =» Conduct STE/ICE GO-NO-GO
test 05
Conduct STE/ICE GO-NO-GO
sending unit test 31
the following components for blockage or obvious damage: w oil filter oil cooler pressure regulator valve oil lines 0il pump pick-up tube and screen Oil pump (not inspected or tested at organizational level.)
Engine damage e the engine for obvious damage (no repair at organizational level)
b High oil consumption High oil consumption is caused by either external or internal leakage External leaks, as
previously discussed, occur around gaskets, seals, hoses, hose connections, filters, and drain plugs |
Trang 11Internal leaks are normally more serious and usually require intermediate maintenance for repair When leaks occur between two systems, both become contaminated For example, if a head gasket leaks, both the cooling system and the lubrication system may be contaminated Internal leaks normally result from gasket
failure
Other common problems that cause high oil consumption are worn or damaged valve guides, turbocharger seals, and cylinder piston rings
Before continuing on, do you remember the one piece of equipment that is used to test for low engine oil pressure or high engine oil consumption and the publication you should use for test information?
You should have said that the STE/ICE is the one piece of
equipment that can be used for these tests, and the publication used at the organizational level is the TM-20 series for the equipment being tested
3503 Inspecting and Testing the Transmission Lubrication System a Inspecting the manual transmission To inspect the
lubrication system on the manual transmission, you check the oil level and look for major leaks Remember, there are no oil
pumps, filters, or other major lubrication components that are subject to failure Primary inspection points are gaskets, seals, filler plugs, and breather valves
As mentioned above, the breather valve should be
inspected It prevents excess pressure buildup within the
transmission (fig 3-35) If —
it becomes clogged, it may == = allow the pressure to build up
to a point that the seals will start leaking To prevent this from happening, keep the
breather free of dirt
Trang 12
b Inspecting and testing the automatic transmission The
automatic transmission can have problems with external leaks from all the previously mentioned items such as gaskets, seals, and hoses The transmission oil coolers, like those on vehicles such as the LVS, are also prime suspects for external leaks The
location of the transmission oil coolers on the LVS and the HMMWV makes them extremely susceptible to damage and to environmental problems like rust and corrosion Keep a particularly close eye on LVS oil coolers; they are extremely unpredictable and can develop serious class III leaks without warning
BREATHER VALVE
Automatic transmissions also
have breather valves (fig
3-36) A plugged breather valve on the automatic transmission will not only Cause premature gasket or seal failure, but will also cause oil to be forced out through
the oil filler tube
Fig 3-36 Breather valve on automatic transmission
Low oil pressure will often cause the transmission to overheat and make excessive noise At the first sign of overheating,
(check the TM for temperature ranges) check the oil filters, lines, hoses, and the oil cooler itself for blockage or damage Overheating is a common problem after the transmission has been serviced A damaged or missing "0" ring seal on the suction tube of the internal oil filter will prevent the oil from reaching the oil pump
Lubricating oil pressure can be tested at the intermediate
maintenance level by performing a lubrication pump pressure test This test will determine the overall serviceability of the
lubricating system Refer to the TM-34 before performing this test
Now, what was the faulty part that could very easily cause enough excessive pressure to build up in either an automatic or manual transmission to cause gaskets and seals to start leaking?
If you said it was the breather valve, you're absolutely correct, and should continue on If you didn't know the answer, you
Trang 133504 Inspecting and Testing the Transfer Case Lubrication System
The transfer case, like almost all other components we've
discussed, is equipped with seals and gaskets As you well know, these components are prime candidates for leaks Some transfers, such as the one in the LVS (fig 3-37) are also equipped with
externally mounted oil pumps and hoses These exposed hoses can be easily damaged if not properly mounted Check the hoses and fittings carefully; Marines sometimes damage them while climbing on the vehicle FEED LINE : LUBRICATION a FEED LINE (HOSE) LUBRICATION FEED LINE (HOSE) OIL LEVEL AND OIL FILL PLUG STRAINER
Fig 3-37 LVS transfer case lubrication system
The procedure for testing the operation of the lubrication pump on the LVS consists of the following steps:
e Check the oil level Make sure the oil is up to the plug hole
e Remove one of the lubrication feed lines
e With the parking brake applied and the wheels chocked, : place the transfer case in neutral
Trang 14e Watch for lubricant to flow from the pump Be patient; it may take a moment for the oil to flow If oil doesn't flow, check the strainer in the lubrication pick up line; it may need cleaning No or very little oil flow
indicates a defective oil pump
So, to check the operation of the oil pump on the transfer case of the LVS, you should watch for lubricant to flow from the
That's right, the answer is the oil pump
The oil level in the transfer case is extremely important A proper level must be maintained to ensure that an adequate amount of oil is pumped to all locations throughout the transfer case As with other components, the transfer case has a breather Keep a close eye on it; a defective breather may lead to leaking seals and gaskets
3505 Inspecting and Testing the Axle Assembly, Nosebox, and Carrier Assembly Lubrication System
Again, don't forget to check seals, gaskets, and drain plugs Inspect wheel seals, flange gaskets, and input/output shaft seals closely; leaks commonly occur in these areas
If you are inspecting the LVS number one axle, remember that the nose box and axle assembly are separated by seals If these seals are bad, you could have oil leaking internally from the nose box into the differential; if this condition goes
Trang 15The number 1 and number 3 axles on the LVS are both equipped with lubricating pumps (figures 3-38 and 3-39) AXLE DIFFERENTIAL CARRIER COVER NOSE BOX LUBRICATING PUMP
Fig 3-38 LVS number 1 axle
Check the operation of the pump on the number 1 axle using the following procedure:
e Remove the oil feed line from the axle differential carrier cover
© Raise the number 1 axle off the ground and support it with jack stands
e Apply the parking brake
e Start the engine and shift to drive e Allow the vehicle to idle
Trang 16Note: The number 3 axle oil pump (fig 3-39) is not checked the same way as the number 1 axle | LUBRICATING PUMP PICK-UP SCREEN AXLE DIFFERENTIAL CARRIER COVER
Fig 3-39 LVS transfer case number 3 axle oil pump
To inspect the number 3 axle oil pump, do the following: © Jack up and support the number 3 axle
e Remove the lubricating pump cover
e Place the transfer case shifter in neutral
e Turn the drive shaft clockwise and see if the lubricating pump gears move Turn the drive shaft enough to allow full rotation of the gears
Note: Always inspect the oil pick-up screen on the carrier : cover for blockage before condemning the oil pump
Inspect the pump cover while it is removed Any Signs of gear binding or scoring on the cover indicates the pump is defective
Complete this lesson by answering the following question about the axle assemblies on the LVS:
Do you use the same procedures to check the oil pump on the number 3 axle as you do on the number 1 axle?
Trang 17No you don't; the procedures are different If you answered this incorrectly, you should review both procedures
Lesson Summary This lesson provided you with the knowledge and skills needed to inspect and test lubrication systems You
identified test equipment and test procedures You also
identified classifications of leaks and stated common areas and causes of leaks
Exercise: Complete items 1 through 11 by performing the action required Check your responses against those listed at the end of this study unit
Listed below are three statements describing leakage of fluid State the classification of each leak in the space provided
1 Class Leakage of fluid great enough to form
drops, but not enough to cause drops that fall from items being checked or inspected
2 Class - Leakage of fluid great enough to form
drops that fall from the item being checked or inspected 3 Class - Leakage of fluid indicated by wetness or
discoloration not great enough to form drops
Item 4 refers to the following situation Read the situation carefully, then answer the item
Situation: You are an organizational mechanic working in the motor pool An operator has just told you that he has a class III leak at the rear of the engine on his vehicle
4 You should verify the of the leak 5 List the parts or areas that are most likely to leak ona
vehicle
a | b Cc
a
Trang 18
Situation: You are a mechanic in an organizational
maintenance unit An operator has reported a vehicle with low engine oil pressure You have inspected the engine and determined that the oil level and type are correct and that there are no external leaks Your next step is to test the engine
6 At the organizational level, what single piece of test equipment can be used to perform all the necessary tests?
7 At the organizational level, what publication provides the procedures for testing low engine oil pressure?
8 What fault could very easily cause enough excessive pressure to build up within a transmission to cause gaskets and seals to start leaking?
9 How do you test the oil pump on the transfer case of the LVS for proper operation?
a Conduct a filter pressure test b Check for pump back pressure
c Remove one of the oil feed lines and check for flow ad Check the pump windings for continuity
10 The pump on the number 1 axle assembly on the LVS is tested by watching oil flow from the feed line that was
disconnected from the
11 The pump on the number 3 axle assembly on the LVS is inspected by turning the drive shaft clockwise and
watching for movement of the lubricating °
UNIT SUMMARY
In this study unit you identified the lubrication systems of motor transport equipment You stated the functions of