B737 Ch70 Std Practices

8/18/2019 B737 Ch70 Std Practices

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Chapter 70-STANDARD PRACTICES

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TERMS AND ABBREVIATIONS 70-00-01/201 TERMS

Associated TermsDefinitionTerm

Blister

Brittle

Buckle

Burn

Burnishing

Burr

Chafing

Chip

Corrosion

Crack

Crazing

Creep

Deformation

Dent

Deviation


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Discontinuity

Distortion

Erosion

Fatigue

Flaking

Fretting

Galling

Gouge

Groove

High spots

High metal

Imbalance

Inclusion

Indication

Looseness

Misalignment

Nick

No Apparent Depth

Noise

Obstruction

Oil-canning (Snapping action)

Parent Metal

Pickup

Pinched

Pit

Porosity


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Rub

Scale

Scratch

Seizure

Shingling

Spalling

Unbalance

Varnish film

Wear

ABBREVIATIONS TermAbbreviation

AVM

CBP

ID

IGB

IGN

IGV

KIAS

NLR

OGV

PB

PC

PCR

PLA

PS12

QAD

RVDT

TACH

TAI


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TCCV

TC1

TC2

TLA

T12

T2

VCD

CONSUMABLE MATERIALS 70-10-01/201

1. General

(1) This procedure contains all the consumable materials you need for the maintenance of the CFM56 engine.

(2) Code numbers refer to materials given in the CFMI Consumable Products Manual.

PRECAUTIONS DURING R/I OF ENGINE COMPONENTS 70-10-02/201

2. General(1) You must be careful when you do maintenance operations in the engine critical areas.(2) Damage to the engine can occur from unwanted materials that go into the engine (FOD) or from engine parts that

are not correctly attached.(3) It is very important that all critical areas of the engine be examined for cleanliness before each engine run.

(4) It is very important that the area around the engine be examined for cleanliness before each engine run.

3. Precautions During the Removal and Installation of Engine Components(1) Engine Critical Areas

(a) Air inlet cowl.(b) Bleed valve compartments.

(c) Interfaces with engine bleeds.

(2) General Precautions(a) Before you do the maintenance, make sure you do these:

1) Remove the contents from your pockets of your work clothes.2) The bottom of your footwear is clean.3) Make sure all of the important areas of the engine are free of tools and materials.4) Make sure the area around the engine is free of tools and materials.5) After you complete the maintenance, make sure you do these:6) Remove all tools and engine parts that you do not use.

7) Attach all clamps and brackets.8) Remove all loose (instrumentation and lockwire) wire.9) Make sure the area of the air inlet cowl and engine bleeds is clear of all unwanted material.10) Use a vacuum cleaner to clean the zones that are not easy to get to.11) Make sure you install the covers.

(3) The Removal of Components and Accessories(a) The maintenance practices procedures for the seals and gaskets are included in Seals (Preformed Packingsand O-rings) and Gaskets (AMM 70-30-01/201).

(b) Do not let the metal tools touch the components and accessories before you remove them.(c) Prevent damage to the openings with clean covers/caps.(d) Prevent damage to the electrical connections when you disconnect the electrical systems.(e) Prevent damage to all ends of the equipment when you remove a component (for example, the gear shafts and

connections).


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(4) Installation of Components and Accessories

(a) Write the type and serial number before you install a component.(b) Visually examine the general condition of the component.

1) Make sure the component is not damaged before you install it.(c) Make sure the mounting faces and seal grooves are clean and not worn.(d) Use only the tools made for the operation.(e) Make sure you see a minimum of one thread in the nuts and chamfers after you tighten the last torque.CAUTION: USE TWO WRENCHES TO REMOVE, INSTALL AND TIGHTEN THE HOSE AND TUBE

COUPLING NUTS. MAKE SURE YOU USE ONE WRENCH TO HOLD THE NIPPLE AND THE OTHERWRENCH TO LOOSEN OR TIGHTEN THE COUPLING NUT. ONE WRENCH CAN CAUSE DAMAGE

TO THE HARDWARE.(f) Make sure you tighten to the given torque values in the sequence of the procedure of operations.(g) Use gloves to hold the bearings and all other parts that can oxidate.(h) Do not use the cold-shrink procedure for the installation of earings.

TEMPORARY MARKING PROCEDURE 70-10-03/201

4. General

(1) Use temporary marks for temporary identification only.(2) Temporary marks are not intended to remain after engine operation.(3) Remove the temporary marks before the operation of the engine.(4) The temporary marks must not cause damage or failure of the parts, if you do not remove the marks.(5) When you make a mark incorrectly, they can be damaged by the high temperatures of engine operation.(6) Temporary marks used to identify parts may no longer be there after an engine run.(7) Incorrect materials used to make temporary marks, when subjected to high temperatures, can cause chemicaldamage to the part and cause possible part failure.

(8) This procedure refers to the materials that were examined by CFM International. You can use these materialssafely on engine parts.(9) If more temporary marking compounds are necessary, refer to CFMI Standard Practices Manual, 70-10-02.

5. Temporary Marking MaterialsCAUTION: WHEN IT IS NECESSARY, MAKE A MARK ON THE ENGINE PARTS. YOU CAN ONLY USE

APPROVED MARKING COMPOUNDS. MARKING COMPOUNDS THAT ARE NOT APPROVED CANCAUSE DAMAGE TO THE ENGINE PARTS.YOU MUST NOT USE GREASE PENCILS OR LEAD (GRAPHITE) PENCILS TO MAKE A MARK ON THECOMBUSTION SECTION AND HOT SECTION PARTS.THESE MATERIALS AND HEAT CAN CAUSE DAMAGE TO THE PARTS.(1) The materials that follow are commercially available to make a mark on the parts:


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LOCK PROCEDURE 70-20-01/201

• General

A. This procedure tells the usual procedures to install this lock device:- the self-locking, hexagonal and castellated nut

B. This procedure tells how to attach parts with the use of these:- The cotter pin.

- The tab washer.- The lockwire.

C. The lock devices are safety devices to keep the fasteners and other parts engaged.D. The lock devices prevent all opposite forces that can cause the fasteners to disengage.

E. Do not use the lock devices to apply or keep a torque.F. The lock devices are related to safety and you must install them with the best shop procedures.

1. Install the Self-Locking, Hexagonal and Castellated

•

Procedure1) You must examine the new or used nuts and compare them with the assembly specifications.

(a) You must discard the nuts that do not agree with the specifications.(2) Make sure the threads of a stud or bolt shank come out of the nuts with a minimum of one thread (unlessotherwise specified)(3) Use a torque wrench to apply the correct torque values.

2. Install the Cotter Pin


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• Procedure

CAUTION: DO NOT USE THE SAME COTTER PINS AGAIN. USE NEW COTTER PINS FOR EACHASSEMBLY OPERATION. WHEN YOU TIGHTEN THE FASTENERS, DO NOT USE MORE THAN THE

MAXIMUM TORQUE VALUE. DAMAGE TO THE EQUIPMENT CAN OCCUR.(1) After you apply the minimum torque to a castellated nut, do these steps:

(a) Tighten the castellated nut until the one slot on the nut is straight with the hole for the cotter pin.

(b) If you cannot align the nut and the hole, then loosen the nut by one-half turn.1) Tighten the castellated nut again.(c) If you cannot correctly align the castellated nut again, then replace the nut.

(2) Install the cotter pin with the head engaged tightly in the slot of the nut.(a) Bend the points of the cotter pin until the head and the top point are tightly engaged against the bolt.

3. Install the Tab Washer

• ProcedureCAUTION: DO NOT USE THE TAB WASHERS AGAIN. USE NEW TAB WASHERS FOR EACHASSEMBLY OPERATION. DAMAGE TO THE EQUIPMENT CAN OCCUR.

(1) Install the tab washer in the correct position.(a) Install the lock tab so it cannot get loose.

(2) Bend the lock tab tightly against the flat side of the nut.

4. Install the Lock Wire • General

(1) The lockwire is a safety device to make sure two or more parts stay together.

(a) If the part starts to become loose, then the lockwire would tighten more to oppose the part in the oppositedirection.(b) When you install a lockwire, use the general instructions and the specified procedures that follow.

(2) General Instructions to Lockwire.

(a) Unless specified differently, the lockwire must be a NC15Fe wire with a 0.032 inch (0.81 mm) diameter.(b) Twist together the two strands with the double-twist procedure to install the lockwire.

1) You get one twist when you turn the wires through an arc of 180 degrees and is equal to one-half a fullturn.

2) You can use the single-strand procedure (see C, Fig. 204) only when it is specified.(c) Do not install the lockwire to cause the wire to wear, fatigue through vibration or become tighter.

NOTE: Use the lockwire to keep the parts engaged.(d) You must install the lockwire only through the holes given.

1) When you do not have a hole, attach the wire to a part adjacent to the wire.NOTE: Make sure the lockwire does not hit the parts. Refer to the instructions in this procedure (refer to F


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and G, Fig. 204).

(e) The maximum length of the lockwire between tension points is 6 inches (152 mm), unless specified

differently.1) When 3 or more fasteners make a group to lockwire together, use the single-strand or the double-twist

procedure.2) A limit in the number of units you can connect with a 24 inch (610 mm) length of wire is the maximum

number of units in a sequence.3) When you install a lockwire to all units that are far apart and in a group, use the double-twist procedure.

NOTE: Do not install the lockwire to more than three units in a sequence (refer to H and I, Fig. 204).

CAUTION: DO NOT TURN THE LOCKWIRE MORE THAN 15 TIMES FOR EACH INCH (25.4 MM). IFYOU DO NOT OBEY, DAMAGE TO THE EQUIPMENT CAN OCCUR.

(f) Pull the lockwire tight while you twist it.1) The lockwire must have a specific number of twists for the diameter of the wire:

a) 9 to 12 twists for each inch (25.4 mm) for 0.020 inch (0.51 mm) diameter wire. b) 7 to 10 twists for each inch (25.4 mm) for 0.032 inch (0.81 mm) diameter wire.

(g) Lockwire the hose and the electrical coupling nuts the same as the tube coupling nuts (refer to F, G, J, K, Land M, Fig. 204).

(h) Be careful when you twist the wire.1) Keep the lockwire tight.

NOTE: Do not overstress the wire or permit it to have nicks, kinks or damage.(I) Correct and incorrect procedures for lockwire practices (refer to Fig. 204, sheet 2).(j) Use the twist tools, which are recommended and locally available, to lockwire (Fig. 205).

(3) Procedures to Lockwire (Fig. 206).CAUTION: DO NOT USE THE SAME LOCKWIRE AGAIN. USE A NEW LOCKWIRE FOR EACHASSEMBLY OPERATION. DAMAGE TO THE EQUIPMENT CAN OCCUR.(a) Examine the lockwire holes to the parts to make sure the holes are aligned correctly.

1) If a part is tightened to the correct torque value, but is not correctly aligned, replace it with a different part.

NOTE: Lockwire holes that are correctly aligned with an installed lockwire will not let the part becomeLoose. Do not tighten more than the torque value limits of all the parts to make sure the holes are aligned.

(b) Put the lockwire through the first part, and bend the top end of the wire along the head of the part or around

it.1) If bent around it, the direction and twist of the strands must come around the part and below the strandsthat point out of the hole.2) If you do this, the loop will stay down and will not move up and become a loose loop (refer to A and B,Fig. 206).

(c) Twist the strands while they are tight until the twisted part is near a hole in the subsequent part.

1) The twisted wire must be in 0.125 inch (3.18 mm) or less of the hole in the other part (refer to C and D,Fig. 206).

(d) If you bend the free strand around the head of the second part, put the top strand through the hole in this part.1) Put the lockwire through the first part, and bend the top end of the wire along the head of the part or

around it.a) If bent around it, the direction and twist of the strands must come around the part and below the

strands that point out of the hole. b) If you do this, the loop will stay down and will not move up and become a loose loop (refer to A and

B, Fig. 206).2) If you bend the free strand on the unit, the direction of the twist is not important.3) If there are more than two units in the sequence, do these steps again (refer to E and F, Fig. 206).

(e) After you connect the last part, do this:1) Continue to turn the wires to make a pigtail of 3 to 6 twists and is 0.250-0.50 inch (6.4-12.7 mm) in

length.2) Cut off the unwanted wire.

3) Bend the end of the lockwire into the part to prevent damage (refer to G and H, Fig. 206).NOTE: All the lockwires must agree usually with the example, not all possible combinations of lockwire isgiven (Fig. 204).


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(f) If the lockwire is not tight, after you install the lockwire with the instructions given before, do this:

1) Use the procedure that follows to make sure you install the lockwire correctly.

2) Apply light, finger-pressure to the middle position of the lockwire span.a) Bend the lockwire in the two directions.

3) Measure the maximum flex you see at the midpoint and compare to these limits:

4) If the lockwire does not agree with these limits, do these steps:

a) Remove the lockwire. b) Install a new lockwire.

(g) Always cut, rather than break, the lockwire so the lockwire holes are not torn or damaged.

5. Safety Cable Installation

6. Crimping Tool Verification


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Lockwire Practices Figure 204 (Sheet 1)


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Lockwire Practices Figure 204 (Sheet 2)


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Example of Lockwire Twist Tools Figure 205

Lockwire Procedure Figure 206


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TIGHTENING PRACTICES AND TORQUE VALUES 70-20-02/201 TORQUE WRENCH SIZE

EXAMPLE


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Use of an Offset Extension Wrench


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Installation and Tightening of Plugs and Tube Fittings


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Minimum Breakaway Torque for Self-Locking Nuts (Fig. 209)

• General(1) This procedure has the definitions, terms and procedures that you use to tighten the fasteners that have threads

(bolts, nuts and fittings).(2) When you turn a fastener around the axis of the fastener you cause torque.

(3) Usually, you will use the torque values that are specified in this procedure.(a) When a installation procedure gives you a torque value, use that torque value.(b) But when an installation procedure tells you to tighten a bolt, but does not give a torque value, refer to 20-50-11/201.

(4) Make sure that you apply the torque accurately.(a) A torque of one pound-inch is a force of one pound applied to a lever at a distance of one inch from the of the

fastener(Whereas one N.m is the force of one Newton you apply to a lever one meter in length).(b) To calculate the torque, you multiply the force that you apply in pounds (Newtons) by the distance of theforce from the axis of the fastener in inches (meters).

(c) The specified torque is the best value for the fastener and the part that it holds. The specified torque will cause the

fastener to hold the part tightly but will not break the fastener or the part.NOTE: Torque values are shown in pound-inches (N.m) to identify it from a force you apply over a distance (work),

which is shown as inch-pounds or joules (J).

• Procedure

(1) Definitions(a) Terms about the procedure to tighten are:1) BOLT - A male part that has threads.2) BREAKAWAY TORQUE - The maximum torque that you must apply before you make the fastener move.3) GROSS TORQUE - The torque that the gage on the torque wrench shows.4) INSTALLED NUT - A nut is referred to as an installed nut when these conditions occur:

- The nut has the specified torque.- The chamfer and 1-1/2 threads of the bolt show above the nut, or the chamfer and 1-1/2 threads of the bolt show

above the lock device.5) MAXIMUM INSTALLATION TORQUE - The highest value to get as the nut is initially installed and sized

("opened up" or "worn in") by the bolt.6) MINIMUM PREVAILING TORQUE - The minimum value you get while the nut or bolt moves from the end of

the first revolution to the end of the second revolution (during the removal of the nut from the bolt or the bolt from athreaded hole).

7) REMOVED NUT - A self-locking nut is removed when you remove the lock part from the bolt. (It is not necessaryfor the nut to be removed from the bolt.)

8) RUN-ON TORQUE - The torque that is necessary to turn a nut or bolt before it is fully engaged (an axial tighteningeffect on the bolt or spacing elements).

9) SEATED NUT or BOLT - A nut or bolt is engaged when its bearing surface touches a spacer. An axial load is puton the bolt when you apply a specified seating torque or compressive force. When you get a measured extention ofthe bolt.

10) SEATING TORQUE - The torque you apply to a specified compressive force to the spacing elements. An axialload or an extension force to a bolt (after the bearing surfaces of the bolt and nut touch the spacing elements).


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11) SPACER, SPACING ELEMENTS - All of the parts (regardless of function, size, shape or material) are held

together by one or more fasteners that have threads.

12) UNSEATED NUT or BOLT - A nut or bolt is unseated when it is removed a minimum of one turn from the seated position. When you remove all the axial load from the bolt.

13) UNSEATING TORQUE - The torque that is necessary to unseat the bearing surface of a nut or bolt from a spacer.(When you remove all the axial load from the bolt).

(2) Procedure to Tighten the Parts.(a) When you tighten the nuts, you must apply the specified torque values.

1) These torque values are given to make sure of the best procedure to tighten the parts for safety functions.(b) On flanges with a large number of bolts and nuts, tighten the pairs of bolts that are opposite to each other.(c) On the same flanges, it is recommended to continue to a last check, clockwise.

1) Make sure all the nuts are tight to the specified torque values.(d) Tighten at a constant rate until you get the specified torque.

1) In some cases, where gaskets or other parts cause a slow permanent set, make sure to measure the torque at the

necessary value after you engage the material.(e) Do not tighten to the last torque value when you first tighten it.NOTE: Tension that is not equal can cause distortion or overstressing of parts.

1) Tighten the bolts to engage the mating parts, in slow and in small steps until the parts are tightly engaged.

2) Complete the procedure to tighten all remaining fasteners independently.a) Tighten to the specified torque value.

3) Do not tighten more than the maximum torque values.

(3) Torque Wrench Sizes

(a) The torque wrenches given below are recommended for use in the indicated ranges.1) Larger wrenches have a larger tolerance, and they can cause important errors.

(4) Use an Offset Extension Wrench (Fig. 201).

(5) Approved Torque Values(a) Approved torque values for the bolts and nuts (does not include reduced head bolts) given in Fig. 202 (pound-

inches) and Fig. 203 (N.m).

(b) For the reduced head bolts, use torque values given in Fig. 204.(c) Approved torque values for the studs and stepped studs in aluminum or magnesium given in Fig. 205.(d) Approved torque values for flared tubes and hose fittings are given in Fig. 206.

(6) Tighten the Plugs and Tube Fittings (Fig. 207 and 208).(a) Assembly procedures change, by the special type of plug or tube fitting that you use.

1) The types you usually find include:a) Non-positioning plugs and unions, with O-rings or other packing that compresses for seals. b) Positioning fittings, with or without back-up washers.c) Universal bulkhead fittings, held in position by locknuts.

(b) Calculate the torque values (Fig. 208) on the correct assembly of the fittings as given below.

1) The Installation of O-rings (packings) on the fittings.a) When the ratio of the O-ring (packing) diameter to the cross section is larger than 20, use a conic sleeve turnedon the fitting until the O-ring (packing) can be moved into a groove of a fitting without damage to it. b) For the diameter ratios less than 20, a conic sleeve is not necessary.NOTE: Not when the O-ring (packing) must be rolled on the threads or splines.c) Lubricate the O-ring (packing) with petrolatum.d) Move the O-ring in the groove of the fitting.

2) Lubricated Surfaces.a) Do not use lubricant on all threads or friction surfaces unless specified differently.

3) Non-positioning fittings.a) Lubricate the packing lightly to prevent cuts by sharp threads. b) Install the packing on the fitting so that the packing is down smoothly in the groove of the fitting (refer to A,Fig. 207).

c) Turn the fitting in the boss.d) Tighten to the specified torque value (refer to B and C, Fig. 207).


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4) Install the fittings (no backup washers).a) Turn the locknut fully on the first section of threads on the fitting (past the packing groove) and on the second

section of threads.

b) Lubricate the packing to prevent cuts by sharp threads.c) Install it carefully on the first section of threads and into the packing groove until it is smooth and touches the

second section of threads.d) Turn the locknut until it almost touches the packing (refer to D, Fig. 207).e) Install the fitting in the boss until the packing touches the countersunk surface.f) Loosen the fitting not more than one turn to put it in the correct position.g) Hold the fitting in its position.

h) Tighten the locknut to the specified torque value (refer to E, Fig. 207).5) Install the fittings (with backup washers).

a) Turn the locknut fully on the first part of the threads on the fitting and on the second part of the threads (thewasher recess must point at the packing groove).

b) Hold the backup washer tightly by its external edge.c) Turn the fitting into the cupped washer (refer to Fig. 207).d) Do not use lubricant.e) Continue to turn the washer on the fitting until the washer is free on the packing groove.

f) Pull out all the slivers of plastic material that you cut from the washer.g) Push the edges of the washer into the recess in the locknut until smoothly engaged.

h) Make sure the threads of the fitting has a clearance when you seat the washer.i) Lubricate and install the packing as told in the step before (refer to G, Fig. 207). j) Hold the locknut in its position with a wrench.k) Turn the fitting into the boss 1.5 turns.l) When it is necessary turn the fitting into the boss up one more turn (total 1.5 to 2.5 turns) to position it.m) Hold the fitting in its position.n) Tighten the locknut to the specified torque value (refer to H, Fig. 207).

6) Universal bulkhead fittings.a) Attach the bulkhead fitting to the bulkhead with a locknut (refer to I, Fig. 207). b) After you tighten the connecting tube or hose nut correctly, do this:- Hold the fitting with a wrench- Tighten the locknut to the specified torque value.

(7) Net Torque(a) At given times, procedures can give a net torque value (which is very important) to tighten a part with a force

the fastener applies.

1) You must control the limits accurately to get a specified quantity to pull the bolt or to give an accuratequantity of hold-down pressure.

(b) The net torque is equal to the gross torque minus the run-on torque.(c) The procedure to find the net torque is in the example that follows:

1) Requirement: To tighten a nut on a bolt to a net torque of 20-40 pound-inches (2.3-4.5 N.m).a) Turn the nut on the bolt.

b) Find the torque necessary to turn the nut before the step to tighten it.c) Write this value down as the run-on torque.

d) If you think the value to be 15 pound-inches (1.7 N.m).2) Add the run-on torque value you find in the step before to the minimum and maximum specified torquevalues.


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(8) Do a Torque Check for the Use of Self-Locking Nuts Again (Fig. 209)

(a) If you use self-locking nuts again, they must keep the minimum breakaway torque limits.(b) Do a torque check as follows:

1) For the minimum breakaway torque on self-locking nuts, refer to Fig. 209.a) This applies to the silver-plated, layered with dry-film and lubricated self-locking nuts. b) The values given are for nuts with no axial load.

2) Do a minimum breakaway torque check as follows:a) Install the nut on a bolt until you can see 2 to 5 threads through the nut.

b) Measure the torque necessary to turn the nut on or off the bolt.CAUTION: DO NOT SQUEEZE OR CRUSH THE ROUND SHAPE OF THE SELF-LOCKING NUT TO

GET THE REQUIRED TORQUE VALUE. DAMAGE TO THE EQUIPMENT CAN OCCUR.3) You must replace all the nuts that do not keep these minimum friction limit

(9) Procedure to Tighten the V-Band Clamps(a) Tighten the V-band nut to 50 percent of the necessary torque.

1) Make sure you engage the coupling on the flanges equally around the outer width.

2) Make sure the seal is correctly engaged, if it is necessary.(b) With a plastic or non-metallic mallet, hit the coupling lightly around its outer width to apply the V-band

tension.(c) While you increase the torque to 100 percent of the specified value, lightly hit the outer width to prevent loads

that are not equal, if it is necessary.(d) After 100 percent of the specified torque is near, hit around the band again.(e) Tighten one more time to the specified torque value.


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SEALS (PERFORMED PACKINGS AND O-RINGS) AND GASKETS-

MAINTENANCE PRACTICES 70-30-02/201

• General(1) The data in this procedure is applicable to all installations that use seals or gaskets.(2) Seal removal, installation and lubrication instructions is given in this procedure.(3) This procedure tells you when you can continue to use a gasket.

• Procedure(1) Removal of the Seal

(a) Do not remove the seals with a sharp or pointed tool (knife-blade or a scriber) which could cause damage to thesurface of the parts.

(2) Lubrication of Seals(a) Lubricate the seals with lubricants recommended in the installation procedure.(b) Apply a light layer of engine oil to the O-rings.

1) If you apply too much lubricant, you can prevent the correct seal installation and can cause contamination.

(3) Installation of the Seal

(a) Use only new seals and rubber items during installation operations.(b) Make sure the seals are in good condition and free from cuts or gouges.

(c) During the seal installation, be careful to install the seal correctly.1) Make sure the seal groove (recess) is free from sharp edges.

(d) For O-rings that must be installed over threads or splines, you must use a conical sleeve, without burrs or sharpedges, to prevent damage to the seal.

(4) Continued use of the Aluminum Gaskets(a) Examine the aluminum gaskets with imbedded flexible seal material for the limits that follow:

1) Examine for nicks, cuts, gouges or openings across the surface of the seal material.a) These are not permitted.2) Examine for hard or brittle seal material.

a) These are not permitted.

3) Examine the surface of the seal material for deformation that could cause a blockage of the seal.a) These are not permitted.

4) For the fuel pump or MEC gasket only, examine the seal material for a minimum of 0.018 inch (0.45 mm) abovethe aluminum surfaces.

5) Examine the full length of the seal surface.

(5) Maintenance of the Aluminum Gaskets

(a) Remove the lifted metal in the bolt hole area with a fine polishing stone or equivalent.1) Be careful not to cause damage to the seal material.

(b) Cut all thin, lacy, seal material that extends beyond the normal seal material on the aluminum surfaces.Be careful not to cut or loosen the bottom of the material.


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FLUORECENT-PENETRANT 70-40-01/201

• GeneralA. This procedure includes two tasks on how to do a fluorescent penetrant inspection. The first task is a portable post-

emulsifiable inspection. The second task is a water washable inspection.B. CFMI recommends the operators use the portable post-emulsifiable system because the water washable inspection

can remove the penetrant indication if too much water is used.

C. It is permitted to substitute a penetrant system with a higher sensitivity (i.e. - substitute a level 3 or 4 for a level 2 asrecommended) if the inspectors that do the inspection have a higher training, knowledge, techniques and experiencein the interpretation of indications.

The higher sensitivity level gives a higher background fluorescence contrast that can lead to irrelevant indications.

STANDARD TOOLS AND EQUIPMENT 70-60-01/201

• General(1) This procedure contains the approved tools and equipment you use in the maintenance of the CFM56 engine.

• Procedure(1) Use this List of Standard Tools and Equipment.

B737 Ch70 Std Practices

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