ARMY TM 9-2815-260-24 AIR FORCE TO 38G1-126-2 MARINE CORPS TM 09244A/09245A-24 4-47 (4) Cover all openings to prevent entry of foreign material. b.     Inspection. (1) Remove oil pressure regulating valve assembly, refer to step a. (2) Inspect cone of oil pressure regulating valve (4, Figure 4-39) for excessive wear or damaged sealing face.  If oil pressure regulating valve shows excessive wear or damaged sealing face, replace both valve (4) and valve seat (5). Refer to next higher level of maintenance. FIGURE 4-39.  OIL PRESSURE REGULATING VALVE ASSEMBLY (3) Inspect spring (3) using the following steps.  Replace per step c., if defective. (a) Measure free length of spring (3).  Free length of spring should be 4.55 in. (115.5 mm). (b) Using a spring tester (DO1168AA or equivalent), apply force to spring (3) until spring is compressed to a length of 1.68 in. (42.5 mm).  Spring tension should be 9.1-11.1 lbs.   (45 N).