TM 9-2815-225-34&P 3-42.  OIL COOLER REPAIR (Contd) LOCATION/ITEM ACTION REMARKS c.  Inspection NOTE   Perform steps 20 and 21 for M915/Big Cam I only.   Perform steps 22 and 23 for M915A1/Big Cam III only. 20. All parts Inspect for cracks, damaged Discard any part where cracks, threads, and excessive corrosion. stripped threads, or excessive corrosion is found. WARNING Compressed air used for cleaning purposes will not exceed 30 psi (207 kPa).  Use only with effective  chip  guarding  and  protective  equipment  such  as  goggles  or  shield,  gloves,  etc. Failure to comply may result in injury to personnel. 21. Filter element (6) Inspect and repair as follows: a.  Seal one end of tube bundle. Refer to steps 21c and d for repair. Install suitable air fitting on opposite end and connect compressed air supply line. Immerse tube bundle in water and apply approximately 40 psi (276 kPa) air pressure.  If air bubbles are observed, mark bundle for repair or replacement. b.  Inspect cover (15) for broken or cracked welds.  Repair or replace as necessary. c.  Header leaks may occur where tubes protrude through plate or where header is soldered in case. d.  Repair damaged tubes by Use caution not to damage inserting a smaller outside adjacent tubes or header material diameter tube inside damaged with heat while soldering.  If more tube.  Cut, flare, and solder both than 5 percent of the tubes are ends. defective, discard filter element (6). 3-226