Mooney M20TN, Service And Maintenance Manual

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MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Page
Date
14
2006
Rev Date
2. IDLER PULLEY AND COMPRESSOR PULLEY
A. Place alignment gauge (Borrough’s Tool No.
8082A) around idler sheave/pulley assembly.
B. The alignment gauge alignment bar must fall
within 0.020 inches of the center of the compressor
sheave outer pulley groove.
C. If the extended end of alignment bar is off center
of groove by more than 0.020 inches, estimate the
number of 0.020 shims necessary to correct the align-
ment.
D. Remove idler sheave assembly and place as
many 0.020 shims, TCM P/N 643956--20, between
idler sheave
and bearing as required to achieve correct alignment
between idler and compressor sheave outer pulley.
When alignment is correct, the extended arm will fall
into the center of the bottom of groove of compressor
outer pulley groove within 0.020 inch.
E. Re--install idler sheave assembly and torque
screw to 800--850 in. lbs.
3. VERIFICATION OF PROPER ALIGNMENT FOR
ALL PULLEYS.
A. After torquing of all sheave assemblies, check
alignment of all pulleys to verify belt will not run with any
misalignment during engine operation.
B. Belt is ready for tensioning. See Section
21--54--04.
21--54--04 -- DRIVE BELT TENSIONING PROCE-
DURE
1. Verify all compressor, starter/accessory drive and
idler pulley mounting hardware is tight and belt is prop-
erly aligned per Section 21--54--03.
2. Loosen jam nut on the adjusting bolt, adjusting bolt
and idler pulley slide nut (Fig. 21--5). The idler pulley
slide nut should be loosened only enough to allow the
slide to move freely. For new belt installations, the ad-
justing bolt should only be turned out enough to allow
installation of the new belt.
3. Install new belt (for new belt installations only).
4. Slide idler pulley snugly against belt and tighten
adjusting bolt finger tight into its socket.
NOTE:
At this stage, idler pulley should be rotatable by
hand beneath belt.
5. Tighten adjusting bolt two full turns.
6. Secure adjusting bolt jam nut (275--325 in. lbs.)
and idler pulley slide nut (300--350 in. lbs.).
7. Confirm belt tension is 50--70 lbs. by one of the fol-
lowing methods:
A. Use a direct reading belt tension gauge such as
Borrough’s Tool No. BT--33--73F. – OR
B. Measure belt deflection under a five (5) lb. load
at the center of the longest belt span. Correct deflection
is 0.3 -- 0.4 inches.
NOTE:
A spring loaded force gauge is required for this
procedure.
8. If belt tension is not within the above tolerance,
loosen adjusting screw jam nut and idler pulley slide nut
and re--adjust the tension.
NOTE:
One (1) full turn of adjusting screw results in
about a ten lb. change in belt tension.
-- WARNING --
DO NOT OVER TIGHTEN BELT. Improper belt
tracking or tension may cause belt damage.
9. After five (5) hours of operation, recheck belt ten-
sion and adjust as required to maintain 50--70 lbs belt
tension.
21--55--00 -- COMPRESSOR ASSEMBLY INSPEC-
TION AND MAINTENANCE PROCEDURE
The compressor assembly requires more inspection
than maintenance since field repair with first line tech-
nicians is limited. Inspection consists of checking for
excessive oil leaks, belt alignment/tension and refriger-
ant leaks. The compressor should be periodically
checked at 500--800 hours of operation in which the fol-
lowing should be performed.
21--55--01 -- SPECIAL TOOLS AND EQUIPMENT
REQUIRED
1. Small hand tools and socket set
2. R--134a charging manifold, with gauges and
hoses
3. R--134a electronic leak detector
4. R--134a refrigerant cylinder
5. Leak check liquid (soapy solution)
6. Hand and eye protection
7. Thread sealant (Loctite # 554)
8. Dry nitrogen, regulated
9. Isopropyl Alcohol, flush liquid
21--55--02 -- COMPRESSOR INSPECTION PROCE-
DURE
1. Verify aircraft power to system is OFF.
2. Remove cowling to gain access to compressor.
3. Inspect belt for alignment per Section 21--54--03.
4. Inspect belt for tension per Section 21--54--04.
5. Visually inspect compressor pulley for excessive
wear, nicks, cracks or looseness.
6. Visually inspect compressor shaft for excessive oil
leaks.
21--54--04
AUGUST 2010