Preliminary Requirements

Procedure

1. SUBTASK 72-32-83-360-072 Remove the Damaged Abradable Seal

   1. Refer to Figure.

   2. 
      CAUTION
      TAKE CARE NOT TO DAMAGE THE LP COMPRESSOR FRONT CASE.

      NOTE

      This Step is an alternative to Step.

      Remove the damaged abradable seal.

      1. Use a scraper.

2. SUBTASK 72-32-83-120-065 Clean the Surfaces which are to be Applied with Silicone Rubber Compound by Water Blast Cleaning

   1. Refer to Figure and Figure.

   2. NOTE

      This Step is an alternative to Step.

      Remove the silicone rubber compound by water blast cleaning.

      1. Refer to the SPM TASK 70-15-01-160-501.

      2. Make test piece of AMS4132.

   3. Do a dimensional inspection.

      1. Use IAE 3J12755 Machining fixture if necessary.

3. SUBTASK 72-32-83-220-196 Examine the Surface from which Silicone Rubber Compound are to be Removed

   1. Refer to Figure.

   2. Fluorescent penetrant examine the surface where silicone rubber compound is removed.

      1. Refer to the SPM TASK 70-23-05-230-501.

      2. Use CoMat 06-064 FLUORESCENT PENETRANT (WATER WASHABLE MEDIUM SENSITIVITY).

4. SUBTASK 72-32-83-380-065 Apply Surface Protection to the LPC Front Case Assembly

   1. Apply the chromate conversion coating for aluminum with a brush to the surface where silicone rubber compound is removed.

      1. Refer to the SPM TASK 70-38-02-300-503.

      2. Use CoMat 01-275 CHROMATE CONVERSION COATING FOR ALUMINIUM.

      3. Apply chromate conversion coating to the surface to in Step.

      4. Dry abrasive blast is not applied in Step.

   2. Use clean cold water and then dry air blast to dry the repaired areas.

5. SUBTASK 72-32-83-120-055 Clean the Surfaces which are to be Applied with Silicon Rubber Compound

   1. Refer to Figure.

   2. Mask the areas which are not to be applied with silicone rubber compound.

      1. Use CoMat 02-005 ADHESIVE TAPE (MASKING).

   3. Dry abrasive blast the molding area.

      1. Use CoMat 05-050 SILICON CARBIDE GRIT.

      2. Use a dry blast system cabinet.

      3. Use an air pressure of 70 psig (483 kPa) at a minimum distance of 6 in. (152 mm) from the air nozzle to the component surface.

   4. Remove the abrasive grit that remains by vacuuming.

      1. Use a vacuum cleaner.

   5. Wipe the blasted surfaces.

      1. Use a CoMat 02-099 LINT-FREE CLOTH made moist with CoMat 01-031 ACETONE (CH3)2CO or CoMat 01-124 ISOPROPYL ALCOHOL.

      2. Refer to the SPM TASK 70-36-06-360-501.

   6. NOTE

      After cleaning, the component must not be touched by hand and must be covered by craft paper, to prevent contamination.

      Air dry for 10 minutes minimum.

6. SUBTASK 72-32-83-360-073 Apply Primer to the Surfaces after Cleaning

   1. NOTE

      The primed surface must have a faint pink color. If there is no color, the primer layer is not continuous. If the color is bright, streaky bright or chalky, the primer is too thick.

      Keep the primer in a small container for single use only. The primer that remains must not be used.

      Immediately after the air dry, apply a very thin layer (thickness 0.0001 in. (0.003 mm.) of primer to the molding surface with the use of a piece of cheese cloth.

      1. Use CoMat 08-032 PRIMER.

      2. Refer to the SPM TASK 70-36-06-360-501.

   2. Cure the primed surface.

      1. Refer to the SPM TASK 70-36-06-360-501.

7. SUBTASK 72-32-83-360-074 Mix the Silicone Rubber Compound

   1. NOTE

      The silicone rubber compound has a shelf life of six months from the date of shipment.

      The compound, as received, must be kept at a temperature not higher than 90 deg F (32 deg C).

      NOTE

      The resin and the catalyst in each kit are chemically matched. Do not mix with the components of other kits.

      Mix the silicone rubber compound with the use of a mixer with a drill press to between 70 and 80 deg F (21 and 27 deg C) for 20 to 30 minutes.

      1. Use CoMat 08-037 DELETED or CoMat 08-038 SILICONE RUBBER COMPOUND.

      2. Refer to the SPM TASK 70-36-06-360-501.

   2. Remove the gases from the mixture with a vacuum of 25 to 50 mm Hg for 30 minutes minimum.

8. SUBTASK 72-32-83-360-075 Mold the Silicone Rubber Compound

   1. Clean the molding fixture.

      1. Use the IAE 3J12718 Molding fixture 1 off.

   2. Attach the component to the molding fixture.

   3. Put the gas free silicone rubber compound into an injector.

      1. Use an injector, air pressure type.

   4. Inject the silicone rubber compound into the component (with the molding fixture attached) until the compound comes out of the vent port of the fixture.

      1. Injection pressure: 35 psig (241.5 kPa).

9. SUBTASK 72-32-83-360-076 Cure the Silicone Rubber Compound

   1. Put the LP compressor front case assembly into an oven.

   2. Cure the removal compound.

      1. Refer to the SPM TASK 70-36-06-360-501.

   3. Remove the component from the molding fixture.

   4. Cure the removed component.

      1. Refer to the SPM TASK 70-36-06-360-501.

10. SUBTASK 72-32-83-220-100 Examine the Repaired Area

    1. Refer to Figure and Figure.

    2. Visually examine the repaired area.

       1. Refer to TASK 72-32-83-200-000 (INSPECTION-000).

    3. Dimensional check the diameter of the repaired area. If necessary, grind the diameter of the repaired area.

    4. Do a hardness check of the repaired area at four equal spaced positions on the circumference.

       1. Use a hardness tester (durometer).

       2. Hardness: ASTM D2240 (durometer 'A') 52 - 65.

11. SUBTASK 72-32-83-220-101 Do a Bond Test to the Repaired Area

    1. Refer to Figure.

    2. NOTE

       The bond test must be done after curing of the rubber compound on the following conditions:

       Inspection gas: Air or nitrogen gas.

       Gas pressure: 400 psig (2760 kPa).

       Inspection position: Change the pattern as necessary to examine the not fully repaired area.

       Probe angle: Approximately 45 degrees.

       Do a bond test to the repaired area.

       1. Use the IAE 3J12775 Bond test fixture 1 off the and the IAE 3J12785 Inspection stand 1 off.

       2. No signs of bulging or air leakage are permitted.

Figure: Replace the abradable seal of LPC front case assembly

Sheet 1



Legend

Replace the abradable seal of LPC front case assembly

Sheet 1

Close

Figure: Dimension requirement after water blast cleaning

Sheet 2



Legend

Dimension requirement after water blast cleaning

Sheet 2

Close

Figure: Replace the abradable seal of LPC front case assembly

Replace the abradable seal of LPC front case assembly



Figure: Replace the abradable seal of the LPC front case assembly

Replace the abradable seal of the LPC front case assembly