The parts that follow are available from Cessna Parts Distribution through an appropriate Cessna Service Station.

Transcription

1 Service Newsletter June 15, 2010 TITLE MECHANICAL AIR CONDITIONER COMPRESSOR DRIVER SHEAVE / PULLEY ALIGNMENT TO Cessna Distributors and Single Engine Service Stations MODELS AFFECTED The following airplanes equipped with a mechanical air conditioning system: Models 350 (LC42-550FG) and 400 (LC41-550FG) DISCUSSION The purpose of this Service Newsletter is to provide instructions to do a check and, if necessary, an adjustment of the alignment of the air conditioner compressor belt drive sheave (pulley) and idler sheave (pulley). You must do a check of the sheave alignment if the drive belt is prematurely worn, if the belt is broken or is missing, if the starter drive assembly has been replaced, or during replacement of the starter drive assembly. Because the compressor is mounted in a fixed position, the alignment is adjusted with the installation of shims at the driver and/or idler sheave. MATERIAL AVAILABILITY The parts that follow are available from Cessna Parts Distribution through an appropriate Cessna Service Station. Part Number Description Qty/Airplane 8082-IA Alignment Tool 1(SeeNOTE) Shim, Driver Sheave Up to 5 (If required) Shim, Idler Sheave Up to 5 (If required) Nut, Self Locking 1 (If required) NOTE: Recommend one per Service Station Page 1 of 8 To obtain satisfactory results, procedures specified in this publication must be accomplished in accordance with accepted methods and prevailing government regulations. Cessna Aircraft Company cannot be responsible for the quality of work performed in accomplishing the requirements of this publication. Cessna Aircraft Company, Customer Service, P.O. Box 7706, Wichita, Kansas 67277, U.S.A. (316) , Facsimile (316) COPYRIGHT 2010

2 ACCOMPLISHMENT INSTRUCTIONS Material Information The parts below will be necessary: NEW P/N QUANTITY DESCRIPTION OLD P/N DISPOSITION 8082-IA* 1 Alignment Tool None None Up to 5 (If required) Shim, Driver None None Sheave Up to 5 (If required) Shim, Idler Sheave None None (If required) Nut Same Discard *The 8082A Alignment Tool is identical and may be used as available. In addition to the above parts, the material that follows, or equivalent, will be necessary: NAME NUMBER MANUFACTURER USE Aviation Engine Oil, 50-Weight Cessna Aircraft Company Cessna Parts Distribution 5800 East Pawnee PO Box 1521 Wichita, KS One or the other of the tools below, or equivalent, will also be necessary: Name Number Manufacturer Use Direct-Read Belt Tension Gauge Burroughs Tool No. BT-33-73F To lubricate the driver sheave nut To measure the V-belt tension Spring Scale Various To measure the V-belt tension Instructions 1. Prepare the airplane for maintenance. A. Electrically ground the airplane. B. Make sure that all switches are in the OFF/NORM position. C. Disconnect external electrical power from the airplane. D. Disconnect the airplane batteries. E. Attach maintenance warning tags to the batteries and external power receptacle that have "DO NOT CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS" writtenonthem. WARNING: Use care when you work around the propeller. Make sure that the magneto switch is in the OFF position before you move the propeller or remove the cowlings. 2. Remove the upper engine cowling for access to the air conditioner compressor. (Refer to the applicable airplane model Airplane Maintenance Manual, Chapter 71, Engine Cowling Maintenance Practices.) Page 2 June 15, 2010

3 3. (Refer to Figure 1.) Remove the air conditioner compressor V-belt. (Refer to the applicable airplane model Airplane Maintenance Manual, Chapter 21, Automatic Climate Control System (ACCS) Maintenance Practices.) A. Remove the belt guard. Keep the attachment hardware. B. Loosen the idler sheave slide nut. C. Loosen the jam nut on the idler sheave adjustment bolt. D. Loosen the idler sheave adjustment bolt. E. Remove the V-belt. (1) If the belt is too tight to remove with the idler sheave slider at the loose end of travel, you must do as follows: (a) (b) Remove the idler sheave slide nut, washer, and bolt. Keep the attachment hardware. Remove the idler sheave and slide assembly from the engine. 4. Do a check and an adjustment of the alignment of the driver sheave. (Refer to the applicable airplane model Airplane Maintenance Manual, Chapter 21, Automatic Climate Control System (ACCS) Maintenance Practices.) A. (Refer to Figure 2.) Put the 8082-IA (8082A) Alignment Tool around the driver sheave. You have the tool in the correct position when the extended end of the tool goes over the upper part of the compressor pulley and the slider is partially engaged in the driver sheave groove. (1) If the alignment tool aligns to within inch of the center of the aft groove in the pulley, removethealignmenttoolandgotostep5. (2) If the alignment tool does not align to within inch of the center of the aft groove of the pulley, adjust the alignment as follows: (a) Make an estimate of how many shims of inch thickness you will need to install to have the correct alignment. CAUTION: Prevent rotation of the engine when you remove and install the driver sheave nut. (b) (c) (d) (e) (f) Use a medium-depth 11/16-inch 12-point socket to remove the driver sheave nut. Put no more than five shims (of inch thickness) on the drive shaft to get the correct alignment between the driver sheave and the compressor pulley. When the alignment is correct, the arm of the tool aligns in the center of the bottom of the compressor pulley groove to within inch. Remove the alignment tool. Use clean 50-weight engine oil to lubricate the a new Self Locking Nut. Install the Self Locking Nut. Full engagement of the nut threads is necessary. CAUTION: Prevent rotation of the engine when you remove and install the driver sheave nut. (g) Torque the Self Locking Nut to 450 to 500 inch-pounds. 5. Do a check and an adjustment, if necessary, of the alignment of the idler sheave (Refer to the applicable airplane model Airplane Maintenance Manual, Chapter 21, Automatic Climate Control System (ACCS) Maintenance Practices.) A. (Refer to Figure 2.) Install the idler sheave and the slide assembly, if you removed them. June 15, 2010 Page 3

4 B. Tighten the slide nut on the slide assembly until the idler pulley has no lateral play. C. Put the 8082-IA (8082A) Alignment Tool around the idler sheave. (1) If the alignment tool aligns to within inch of the center of the aft groove in the compressor pulley, remove the alignment tool and go to Step 6. (2) If the alignment tool does not align to within inch of the center of the aft groove of the compressor pulley, adjust the alignment as follows: (a) (b) (c) (d) (e) (f) Make an estimate of how many shims of inch thickness you will need to install to have the correct alignment. Remove the idler sheave bolt, sheave, and spacer from the idler sheave slider. Put the necessary number of shims (of inch thickness) on the aft side of the spacer to have the correct alignment between the idler sheave and the compressor pulley. When the alignment is correct, the arm of the tool aligns in the center of the bottom of the compressor pulley groove to within inch. Install the spacer, shims, idler sheave, and bolt. Torque the bolt to 800 to 850 inch pounds. NOTE: You can final torque the bolt with the idler sheave and the slide assembly not installed in the airplane. Remove the alignment tool. 6. Install the compressor drive V-belt. A. Put the V-belt on the aft groove of the compressor pulley and the driver sheave. B. Install the belt guard with the kept hardware. C. Torque the bolts to 275 to 325 inch-pounds and use safety wire to safety the bolts. D. If removed, install the idler sheave slider assembly. E. Make sure that the idler sheave slide nut is just loose enough to let the slide move freely. F. Put the V-belt in position around the idler sheave. G. Move the idler sheave tightly against the V-belt and tighten the adjustment bolt finger tight. H. Make sure that you can turn with your hands the idler sheave under the belt. I. Tighten the adjustment bolt two more turns. J. (Refer to Figure 1.) Use one or the other of the methods that follow to make sure that the belt tensionis50to70pounds: Use a direct reading belt tension gauge (Burroughs Tool No. BT-33-73F or equivalent) to measure the belt tension. Measure the belt deflection under a five-pound load at the center of the longest belt span. Belt deflection must be 0.30 to 0.40 inch. K. Tighten the adjustment bolt jam nut and torque to 275 to 325 inch-pounds. CAUTION: Do not tighten the V-belt too much. L. If the V-belt tension is not from 50 to 70 pounds, do as follows: (1) Loosen the adjustment bolt jam nut and the idler sheave slide nut. (2) Adjust the tension again. Page 4 June 15, 2010

5 NOTE: One full turn of the adjustment bolt makes approximately ten pounds of change in the belt tension. M. Torque the idler sheave slide nut to inch-pounds. 7. Install the upper engine cowling. (Refer to the applicable airplane model Airplane Maintenance Manual, Chapter 71, Engine Cowling Maintenance Practices.) 8. Remove maintenance warning tags and connect the airplane batteries. 9. After approximately five hours of operation, do a check of the belt tension again and adjust to the specified tension as necessary. June 15, 2010 Page 5

6 Figure 1. Mechanical Air Conditioner Compressor Driver Sheave / Pulley Alignment (Sheet 1) Page 6 June 15, 2010

7 Figure A Alignment Tool (Sheet 1) June 15, 2010 Page 7

8 * * * * * * * Page 8 June 15, 2010

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