Pratt & Whitney Canada Maintenance Manual

CHAPTERSECTION PAGE DATE

LEP 1 Jun 05/20092 blank Jun 05/2009

Contents 1 Jun 05/20092 blank Jun 05/2009

75-30-00MaintenancePractices

201 Jun 05/2009202 Jun 05/2009203 Jun 05/2009204 Jun 05/2009205 Jun 05/2009206 Jun 05/2009207 Jun 05/2009208 Jun 05/2009209 Jun 05/2009210 Jun 05/2009211 Jun 05/2009212 Jun 05/2009213 Jun 05/2009214 Jun 05/2009215 Jun 05/2009216 Jun 05/2009217 Jun 05/2009218 Jun 05/2009219 Jun 05/2009220 Jun 05/2009221 Jun 05/2009222 Jun 05/2009223 Jun 05/2009224 Jun 05/2009225 Jun 05/2009226 Jun 05/2009227 Jun 05/2009228 Jun 05/2009

PRATT & WHITNEY CANADAMAINTENANCE MANUAL

MANUAL PART NO. 3017042

LIST OF EFFECTIVE PAGES

Page 1/275-30 LEP Jun 05/2009

P&WC Proprietary Information. Subject to the restrictions on the title page.

COMPRESSOR BLEED VALVE - MAINTENANCE PRACTICES 75-30-00

1. General 201

2. Consumable Materials 201

3. Special Tools 201

4. Fixtures, Equipment and Supplier Tools 201

5. Removal/Installation 201

A. Removal 201

B. Installation 203

6. Adjustment/Test (Pre-SB5444) 203

A. Metering Plug Replacement (Pre-SB5380) 204

B. Metering Plug Replacement (Post-SB5380) 204

C. Test 204

D. Check 205

7. Adjustment/Test (Post-SB5444). 207

A. Initial Setting 207

B. Leak Test 209

C. In-situ Closing Point Check 217

8. Approved Repairs 219

A. Diaphragm Replacement (Pre-SB5351(R1)/SB5330 only) 219

B. Diaphragm Replacement (Post-SB5330) 223

TABLE OF CONTENTSSUBJECT PAGE



Page 1/275-30 CONTENTS Jun 05/2009


COMPRESSOR BLEED VALVE - MAINTENANCE PRACTICES

1. General

A. Personnel involved in maintenance practices should refer to Chapter 70-00-00,STANDARD PRACTICES to familiarize themselves with general procedures.

B. For additional information regarding Special Tools and Fixtures, Equipment, andConsumable Materials referred to in this section, refer to section TOOLS/FIX/EQUIP orCONSUMABLE MATERIALS respectively.

2. Consumable Materials

The consumable materials listed below are used in the following procedures.

Item No. Name

PWC05-089 LockwirePWC09-003 CompoundPWC11-027 Petroleum SolventPWC09-002A Locking and Retaining Compound

3. Special Tools

The special tools listed below are used in the following procedures.

Tool No. Name

PWC50041 Bracket AssemblyPWC70076 Bracket AssemblyPWC70513 Bracket Assembly

4. Fixtures, Equipment and Supplier Tools

Not Applicable

5. Removal/Installation (Ref. Fig. 201)

A. Removal

(1) If the engine has a bleed air case, remove the bleed air case (Ref. 72-20-00).

(2) Remove the lockwire from the bolts (3).

(3) Remove the four bolts (3), and the washers (4).

(4) Pre-SB5067: Remove the bleed valve (2) with spring pin (6).

(5) Post-SB5067: Remove the bleed valve (2).

NOTE: For Post SB5067, the spring pin is part of the bleed valve (2)

(6) Pre-SB5067: Remove and discard the packing (1) and (5).



75-30-00 Page 201COMPRESSOR BLEED VALVE - MAINTENANCE PRACTICES Jun 05/2009


6

5

4

3

2

1

PRE−SB5067

5

2

3

4

POST−SB5067

C3067D

Compressor Bleed Valve - Removal/Installation (Typical)Figure 201





(7) Post-SB5067: Remove and discard the packing (5).

B. Installation

CAUTION: DO NOT INSTALL PRE-SB5330 COMPRESSOR BLEED VALVE ONPOST-SB5351 ENGINE.

(1) Pre-SB5067: Install a new preformed packing (1) on the bleed valve (2).

(2) Install new packing (5) on the bleed valve (2).

(3) On the bleed valve (2), make sure the piston travel moves freely.

(4) Pre-SB5067: Install the bleed valve assembly (2) on gas generator with the springpin (6).

(5) Post-SB5067: Install the bleed valve assembly (2) on gas generator.

(6) Install the four bolts (3), and the washers (4).

(7) Pre-SB5067: Torque the bolts (3) from 25 to 35 lb.in ( 2.8 to 3.9 N.m.).

(8) Post-SB5067: Torque the bolts (3) from 16 to 20 lb.in ( 1.8 to 2.3 N.m.).

(9) Install the lockwire on the bolts (3).

(10) If the engine has a bleed air case, install the bleed air case (Ref. 72-20-00).

6. Adjustment/Test (Pre-SB5444)

NOTE: 1. Pre-SB5380: Later compressor bleed valves are provided with classified meteringplug sets (Ref. Illustrated Parts Catalog). The classified sets are introduced tocontrol the valve closing point to suit individual power sections. The lower the classnumber the later the valve closes.

NOTE: 2. Post-SB5380: The compressor bleed valve assembly is provided with a secondarymetering orifice plug which controls the closing point on individual engines andprevents engine surge. The lower the part number suffix (smaller orifice size), theearlier the bleed valve closes.

Key to Figure 201

1. Preformed Packing (Pre-SB5067 only)2. Bleed Valve3. Bolt4. Washer5. Preformed Packing6. Spring Pin (Pre-SB5067 only)





A. Metering Plug Replacement (Pre-SB5380) (Ref. Fig. 202)

CAUTION: PLUG SETS MUST NOT BE CHANGED EXCEPT AS SPECIFIED INFAULT ISOLATION. PLUGS MUST BE USED IN COMPLETE SETS.

(1) Obtain plug set required to solve problem (Ref. 72-00-00, ENGINE - FAULTISOLATION).

NOTE: On valves not provided with classified metering plugs sets, replacementmetering plugs must be the same size as original.

(a) Cut lockwire, remove final metering plug (4), blanking plug (2) and preformedpackings (5).

(b) Using screwdriver, remove primary metering plug (3).

(c) Clean replacement metering plugs in solvent (PWC11-027). If necessary, use awooden dowel to clean orifices.

(d) Install new preformed packings (5) on plugs (2 and 4).

(e) Install primary metering plug (3), torque 10 to 15 lb.in.

(f) Install blanking plug (2). Torque 15 to 20 lb.in.

(g) Install final metering plug (4). Torque 35 to 40 lb.in.

(h) Lockwire plugs (2 and 4).

B. Metering Plug Replacement (Post-SB5380) (Ref. Fig. 202)

CAUTION: PLUG MUST NOT BE CHANGED EXCEPT AS SPECIFIED IN FAULTISOLATION.

(1) Obtain plug required to solve problem (Ref. 72-00-00, ENGINE - FAULT ISOLATION).

(a) Cut lockwire, remove final metering plug (4) and preformed packing (5).

(b) Clean replacement metering plug in solvent (PWC11-027). If necessary, use awooden dowel to clean orifice.

(c) Install new preformed packing (5) on plug ( 4).

(d) Install final metering plug (4). Torque 35 to 40 lb.in.

(e) Lockwire plug (4).

C. Test (Ref. Fig. 202)

(1) Remove bleed valve and check that Pre-SB5351 (R1)/SB5330 piston moves freelythrough its full travel in housing bore.

(2) On Post-SB5351 (R1)/SB5330 with valve in horizontal position ensure that a forceof 1.5 to 2.0 lbs is required to move the piston in an opening direction.





(3) Blank off P3 air inlet (6) in valve housing and remove final metering plug (4).

(4) Inspect plug (4) for contamination. If necessary, clean with solvent (PWC11-027)using a small artist-type brush.

(5) Remove blanking plug (2) and primary metering plug (3) (Ref. Subpara. A.,preceding).

(6) Clean metering plug (3) with solvent (PWC11-027) using a wooden dowel to cleanorifice.

(7) Install primary metering plug (3), torque 10 to 15 lb.in.

(8) Install blanking plug (2), torque 15 to 20 lb.in.

(9) Install test adapter, complete with preformed packing (5), in final metering plug port.

(10) Pre-SB5331 (R1)/SB5330 units pressurize to 40 ± 5 psig with clean, filteredshop air or nitrogen. Seal off valve at this pressure. Maximum leakage allowedafter 5 minutes is 5 psig.

NOTE: If pressure test is unsatisfactory on Pre-SB5331 (R1)/SB5330 units,proceed as follows:Replace Pre-SB5067 bleed valves or on Post-SB5067 and subsequentunits, replace diaphragm (Ref. Para.8.).

(11) Post-SB5351 (R1)/SB5330 units, pressurize to 55 ± 5 psig with clean, filtered shopair or nitrogen. Seal off valve at this pressure. If leakage exceeds 0.5 psi over aone-minute period, return valve for overhaul.

(12) Remove test adapter and reinstall final metering plug (4), complete with newpreformed packing (5). Torque plug 35 to 40 lb.in. and lockwire.

(13) Lockwire plugs (2 and 4).

D. Check

NOTE: Check is performed with bleed valve in-situ.

(1) Preparation for Check (Ref. Fig. 203).

CAUTION: USE CARE TO PREVENT ENTRY OF FOREIGN OBJECTS INTOENGINE.

(a) Secure compressor bleed valve (3) and bracket assembly (1) (PWC50041) withfour bolts (2) and washers. Torque bolts 16 to 20 lb.in.

(b) Attach flexible tube to bracket assembly (1).

(c) Re-install bleed air case (Ref. 72-20-00).

(d) Insert other end of tube into clear container of water.





45

1

2

5

3

6

C7739A

Compressor Bleed Valve Metering PlugsFigure 202





(2) Compressor Bleed Valve Closing Point Check

(a) Start engine (Ref. 71-00-00) and allow gas generator speed to stabilize atground-idle.

(b) Note and record outside air temperature.

(c) Slowly accelerate engine until bubbles cease to flow through water in container.

(d) Plot closing point of bleed valve on graph (Ref. Fig. 204). Closing point shallbe within the gas generator speed band for indicated air temperature.

NOTE: If closing point exceeded, slowly decelerate gas generator speed untilbubbles are observed and repeat steps (c) and (d).

(e) Shutdown engine (Ref. 71-00-00).

NOTE: The compressor bleed valve assembly is provided with classifiedorifice(s) which control the closing point on individual engines andprevents engine surge. On Pre-SB5380 engines, the lower theclassification the later the bleed valve closes and for Post-SB5380engines, the lower the part number suffix the earlier the bleed valvecloses. One class or part number suffix change has an effect ofapproximately one percent on Ng.

7. Adjustment/Test (Post-SB5444).

A. Initial Setting

CAUTION: DO AN INITIAL BLEED VALVE ADJUSTMENT SCREW SETTING ON NEW OROVERHAULED BLEED VALVES.

(1) Turn the adjustment screw 11⁄2 turns or 9 flats of the screw clockwise to change themanufacturer’s original factory setting.

NOTE: The manufacturer’s original factory setting is preset for general engineapplications. The adjustment screw requires a different setting to obtainsatisfactory closing point check.

Key to Figure 202

1. Cover2. Plug3. Primary Metering Plug4. Final Metering Plug5. Preformed Packing6. P3 Air Inlet





DETAIL A (TYPICAL)

WATER

A

4

4

1

23

5

1.5 IN.(38.10 mm)MAX. DEPTHOF TUBEIMMERSION.

C24665A

Bracket Assembly for Compressor Bleed Valve Closing Point CheckFigure 203

PRE-SB5444





B. Leak Test (Ref. Figs. 205 and 206)

CAUTION: OVERPRESSURIZATION OF THE BLEED VALVE BEYOND RECOMMENDEDPRESSURE MAY DAMAGE THE BLEED VALVE AND CAUSE INJURIES.

NOTE: Refer to Figure 207, for details for manufacturing test fixture.

(1) Install new preformed packing (4, Fig. 201) on spring pin.

(2) Secure bleed valve to the test fixture (Ref. Fig. 207) with bolts and torque 16 to20 lb.in.

(3) Remove final metering plug (1, Fig. 206) and preformed packing (7) from bleedvalve cover.

(4) Install a suitable blanking plug with preformed packing and torque plug 15 to 20 lb.in.

NOTE: Plug thread size is 0.250-28 inch.

(5) Set the pressure regulator to zero.

(6) Connect a clean dry compressed air supply to fixture.

(7) Open the shut-off valve. Increase the pressure regulator setting until the pressuregage indication is 35 to 45 psig.

(8) Apply leak-test fluid (PWC05-007) to all air line connections, blanking plugs andbleed valve cover flange. Check for leakage. Rectify as required.

(9) With the gage reading 35 to 45 psig, note the reading and close the shut-off valve.A pressure drop over a period of five minutes must not exceed 10 psig.

(a) If the leakage rate is exceeded, send complete compressor bleed valve to anauthorized accessory repair facility.

(10) Disconnect the air supply from regulator. Set pressure regulator to zero to releasepressure from bleed valve.

(11) Remove bleed valve from fixture. Remove blanking plug. Install new preformedpacking (7) on metering plug (1) and install metering plug in valve cover. Torqueplug 15 to 20 lb. in. and secure with lockwire (PWC05-089).

Key to Figure 203

1. Bracket Assembly (PWC50041)2. Bolt3. Bleed Valve4. Rubber Tube5. Container





98

97

BLEED VALVE CLOSING BAND

OUTSIDE AIR TEMPERATURE (OAT)

PE

RC

EN

TAG

E O

F G

AS

GE

NE

RA

TOR

SP

EE

D (

%N

g)

96

95

94

93

92

91

90

89

88

87

86

85

84

83

82

81

80

79

78−40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100

AREA REJECTC

AREA REJECTC

BANDA

ACCEPTABLE

BAND BACCEPTABLE IF

NO S

URGE

10−20−30−40 0−10 20 30 35 ( C)

( F)

PT6T−3 ST6T−75 / 76

C64132

Compressor Bleed Valve Closing PointFigure 204 (Sheet 1 of 6)

PT6T-3, PT6T-3B (PRE-SB5330) (POST-SB5274)





−40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100−30−40 −20 −10 0 10 20 30 35

( F)( C)

o

o

96

95

94

93

92

91

90

89

88

87

86

85

84

83

82

81

80

79

97


PERC

ENTA

GE

OF

GAS

GEN

ERAT

OR

SPEE

D (%

Ng)

AREA ’B’ − REJECT


BAND ’A’ −

ACCEPTABLE

C25700

Compressor Bleed Valve Closing PointFigure 204 (Sheet 2)

PT6T-3 (PRE-SB5274) (PRE-SB5444) (POST-SB5330)





−40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100 ( F)°81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

PERC

ENTA

GE

OF

GAS

GEN

ERAT

OR

SPEE

D (%

Ng)

OUTSIDE AIR TEMPERATURE (OAT)−30−40 −20 −10 0 10 20 30 35 ( C)°

98



BAND ’A’ −

ACCEPTABLE

C25701


PT6T-3B (POST-SB5330)





−40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100 ( F)°81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

PERC

ENTA

GE

OF

GAS

GEN

ERAT

OR

SPEE

D (%

Ng)

OUTSIDE AIR TEMPERATURE (OAT)−30−40 −20 −10 0 10 20 30 35 ( C)°

98



BAND ’A’ −

ACCEPTABLE

C39418


PT6T-3B, PT6T-3BE (PRE-SB5274) (PRE-5444)





98

97

PT6T−6 PT6T−3BBLEED VALVE CLOSING BAND


PE

RC

EN

TAG

E O

F G

AS

GE

NE

RA

TOR

SP

EE

D (

%N

g)

96

95

94

93

92

91

90

89

88

87

86

85

84

83

82

81

80

79

78−40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100

AREA REJECTC

AREA REJECTC

BANDA

ACCEPTABLE

BAND BACCEPTABLE IF

NO S

URGE

10−20−30−40 0−10 20 30 35 ( C)

( F)

C64131


PT6T-3, PT6T-3B (PRE-SB5330) (POST-5274)






−50 −40 −30 −20 −10 0 10 20 30 40 5079%

80%

81%

82%

83%

84%

85%

86%

87%

88%

89%

90%

91%

92%

93%

94%

95%

96%

Alt = 0Kft

Alt = 5Kft

Alt = 10Kft

Alt = 15Kft

Alt = 20Kft

TOLERANCE = −0.0%+2.1%

( °C )

PERC

ENTA

GE

OF

GAS

GEN

ERAT

OR

SPEE

D (%

Ng)

C75363F


(POST-SB5444)





Px DIAGNOSTICPORT

0−40 PSI

SHUT−OFFVALVE

FILTER

SHOP AIR

REGULATOR

DIFFUSER

FIXEDSECONDARYVENTURI

ADJUSTABLEPRIMARYORIFICE

0−75 PSI

THIS GAGE IS REQUIREDFOR CALIBRATION

TEST ONLY.REMOVE FOR LEAK TEST.

TEST FIXTURE

C71848

Compressor Bleed Valve Test (Typical)Figure 205





C. In-situ Closing Point Check

CAUTION: DO AN INITIAL BOV ADJUSTMENT SCREW SETTING ON A NEW OROVERHAULED VALVE ONLY.

NOTE: Bleed valve closing point check is recommended when troubleshooting engineperformance/surge problems (Ref. 72-00-00, Fault Isolation).

(1) Do an initial BOV adjustment screw setting as follows:

(a) Turn the adjustment screw 1.5 turns or nine flats of the screw, clockwise tochange the manufacturer’s adjustment screw setting.

(2) Preparation for check (Ref. Fig. 209)

NOTE: PWC70513 is a complete bubbler test kit, consisting of a bracket, tubeand water container. PWC70076 consists of a bracket and tube assemblyonly.

(a) Position bubbler assembly (1) (PWC70513) or (PWC70076) on compressorbleed valve assembly (3).

(b) Insert a piece of 0.001 inch shim stock between the bracket assembly tube endand the compressor bleed valve flange and adjust bracket assembly accordinglyby loosening the hexagonal cap screws (2).

(c) Ensure the tube end secures the shim to the compressor bleed valve flangeand the flared end of the tube of the bracket assembly is in the groove madeby the compressor bleed valve and the seat. Re-torque the hexagonal capscrews (2) using 16 to 20 lb.in.

(d) Secure the compressor bleed valve and bracket assembly with the four boltsand washers. Torque bolts 16 to 20 lb.in.

(e) Attach flexible tube (4) to bracket assembly (1).

CAUTION: MAKE SURE THERE IS NO INTERFERENCE BETWEEN THECOMPRESSOR BLEED VALVE PISTON TRAVEL AND THE TUBE OFTHE BRACKET ASSEMBLY.

(f) Insert other end of tube into clear container of water (5) where maximum depthof tube immersion shall not exceed 1.5 inches. Ensure the container is vented.

(g) Set the cabin pressure switch to OFF.

(h) Start engine (Ref. 71-00-00) and allow gas generator speed to stabilize atground idle.

(i) Note and record outside air temperature.





ADJUSTMENTSTEM

NOTCH

LOCKBOLT

1

2

3

4

5

6

7

C73673A

Compressor Bleed Valve AssemblyFigure 206





(j) Slowly accelerate engine until bubbles cease to flow through the water incontainer. Do not exceed 97% (37,000 rpm). If bubbles continue at 37,000rpm, adjust compressor bleed valve by 3 flats counterclockwise and repeat.

NOTE: Ng and OAT.

(k) Plot closing point of bleed valve on graph (Ref. Fig. 204).

1 Closing point shall be within the gas generator speed range for indicatedair temperature.

NOTE: A BOV set to close too soon or too late may contribute tocompressor stalls.

(l) Remove and adjust bleed valve closing point as required. Repeat Steps C.(f)through C.(k) in order that Ng at the bleed valve closing point falls within limits(Ref. Fig. 204):

NOTE: If closing point exceeded, slowly decelerate gas generator speed untilbubbles are observed and repeat steps above.

1 Loosen lock screw (2, Fig. 206).

2 Turn the adjustment stem (3) until Ng falls within limits.

NOTE: Clockwise rotation (one flat, 60 degree) rotation of the adjustmentstem (3) will increase Ng closing point of approximately 2%.

3 Tighten double hex lock screw (2) 17 to 20 lb.in.

(m) Remove bracket assembly (1) from compressor bleed valve (3) and securebleed valve (Ref. 5.B.).

8. Approved Repairs

A. Diaphragm Replacement (Pre-SB5351(R1)/SB5330 only) (Ref. Fig. 210)

(1) Remove nuts (1) and washers (2).

(2) Remove cover (3) from housing (10).

Key to Figure 206

1. Final Metering Plug2. Self-locking Screw3. Adjustment Stem4. Piston5. Valve Housing6. Blanking Plug7. Preformed Packing





°

×

22 30’

DRILL AND TAP 4 PLCS0.190−32 UNJF 0.750

°22 30’

DRILL AND TAP TOACCOMODATE AIR

SUPPLY EQUIPMENT

0.750

1.500

4.100 DIA.

2.750 DIA.

0.750

4.100 DIA.

3.250DIA.

DRILL HOLE13/64 DIA. (0.203)

BOLT HOLE0.190−32 UNJF

PIN HOLE13/64 DIA. (0.203)

MATERIAL: ALUMINUM

C71849

Compressor Bleed Valve Test FixtureFigure 207

LOCAL MANUFACTURE





DELETED

C00000

Compressor Bleed Valve Closing PointFigure 208

(POST-SB5444)





DETAIL A (TYPICAL)

WATER

A

MAX. DEPTHOF TUBE IMMERSION.

1.5 IN. (38.10 mm)

5

4

3 2

1

4

C76914A

Bracket Assembly for Compressor Bleed Valve Closing Point CheckFigure 209

(POST-SB5444)





(3) Remove bolts (4).

(4) Remove retaining plate (5) and diaphragm (6) from piston. Discard diaphragm.

(5) Using cotton swab moistened with petroleum solvent (PWC11-027) lightly wipe boreof spacer sleeve (7).

NOTE: All dark traces cannot be removed as sleeve is graphite impregnated.

(6) Using cloth moistened with solvent (PWC11-027) wipe inside of cover (3).

(7) Lightly smear piston top and mating flange of housing with compound (PWC09-003),particularly the area around metering plug (8). Ensure metering plug remains dryand orifice is unobstructed. Remove any excess compound inadvertently applied toother surfaces.

(8) Install new diaphragm (6) with fabric side towards piston. Align bolt holes.

(9) Install retaining plate (5) on diaphragm and secure with bolts (4). Torque bolts 11 to15 lb.in. and lockwire.

(10) Locate diaphragm skirt over studs on housing flange.

(11) Lightly smear cover mating flange with compound (PWC09-003). Locate cover onvalve housing, move piston up and down to ensure that diaphragm rolls correctlybetween piston and housing. Secure cover with four self-locking nuts (1) and washers(2). Check run-on torque and add 16 to 20 lb.in.

(12) Carry out functional check (Ref. Para. 6.C.).

B. Diaphragm Replacement (Post-SB5330) (Ref. Fig. 210, Sheet 2)

(1) Remove nuts (1) and washers (2).

(2) Remove cover (3) from housing (10).

(3) Remove bolts (4).

(4) Remove retaining plate (5) and diaphragm (6) from piston. Discard diaphragm.

(5) Remove two screws (12) and compressor bleed valve seat (11).

(6) Locate the three piston dampers on piston (insitu). Using an approved marker,identify each one by writing a number on the piston surface next to each damper.

Key to Figure 209

1. Bubbler Assembly (PWC70513 or PWC70076)2. Bolt3. Bleed Valve4. Rubber Tube5. Container





3

4

5

6

78

9

10

2

1

C3930

Compressor Bleed Valve Diaphragm ReplacementFigure 210 (Sheet 1 of 2)

Pre-SB531R1/5330





Key to Figure 210

1. Self-locking Nut2. Washer3. Cover4. Bolt5. Retaining Plate6. Diaphragm7. Spacer Sleeve8. Primary Metering Plug9. Piston

10. Housing11. Compressor Bleed Valve Seat12. Screw13. Damper Retainer (Post-SB5330)14. Spring (Post-SB5330)15. Bushing (Post-SB5330)





1

2

3

4

5

6

7

10

8

9

11

12

13

14

15

C71179

Compressor Bleed Valve Diaphragm ReplacementFigure 210 (Sheet 2)

Post-SB5330





(7) Remove damper components and store in separate plastic bags identified withcorresponding location number (on piston surface) as follows:

(a) Index mark the retainer and position to each other.

(b) Remove damper retainer (13) from piston. Record the number of turns andfraction of a turn from index mark (on piston) until retainer is fully releasedfrom the piston.

(c) Place retainer in respective plastic bag. Remove spring (14) and bushing (15)from piston and place in bag with retainer.

(8) Repeat step (7) for the remaining two dampers.

(9) Using cotton swab moistened with petroleum solvent (PWC11-027) lightly wipe boreof spacer sleeve (7).

NOTE: All dark traces cannot be removed as sleeve is graphite impregnated.

(10) Using cloth moistened with solvent (PWC11-027) wipe inside of cover (3).

(11) Lightly smear piston top and mating flange of housing with compound (PWC09-003),particularly the area around metering plug (8). Ensure metering plug remains dryand orifice is unobstructed. Remove any excess compound inadvertently applied toother surfaces.

(12) Install new diaphragm (6) with fabric side towards piston. Align bolt holes.

(13) Install retaining plate (5) on diaphragm and secure with bolts (4). Torque bolts 11 to15 lb.in. and lockwire.

(14) Lightly smear cover mating flange with compound (PWC09-003). Locate cover onvalve housing, move piston up and down to ensure that diaphragm rolls correctlybetween piston and housing. Secure cover with four self-locking nuts (1) and washers(2). Check run-on torque and add 16 to 20 lb.in.

(15) Assemble and install dampers in piston as follows:

(a) Withdraw piston towards seat end of housing until damper orifices areexposed.

CAUTION: TO ENSURE BUSHINGS AND SPRINGS REMAIN IN POSITIONDURING ASSEMBLY, INSERT EACH DAMPER ASSEMBLY FACINGUPWARDS, AND SCREW IN FOR APPROXIMATELY 75% OFTHE REQUIRED NUMBER OF TURNS.

(b) Install three damper bushings (15) and springs (14) in respective retainers.Apply sealing compound (PWC09-002A) to threads.





(c) Adjust retainers equally. Turn each retainer the same number of turns that werenecessary to remove them.

NOTE: When installed, retainers must be 0.020 to 0.100 in. below surface ofpiston.

(d) Before sealant has time to cure, adjust helical compression spring retainersuntil a force of 1.0 to 2.0 lb. is required to move the compressor bleed valvepiston.

(e) Allow sealant to cure at room temperature for 24 hours. As an alternative, oneof the following methods can be used to reduce the time required to cure thesealant:

1 Allow to stand at room temperature for one hour, then bake at 212 °F (100°C) for 15 minutes.

2 Allow to stand at room temperature for one hour, then bake at 300 °F (149°C) for 10 minutes.

3 Allow to stand at room temperature for one hour, with the compressorbleed valve installed in the engine, run the engine at idle for five minutes.

(f) Push compressor bleed valve piston into compressor bleed valve housingassembly. Install compressor bleed valve seat (11) and two screws (12).Torque screws 6 to 7 lb. in.

(16) Carry out functional check (Ref. Para. 6.C.).





Pratt & Whitney Canada Maintenance Manual

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