TM 10-3930-659-34 4-6. CYLINDER HEAD ASSEMBLY REPAIR (Con’t). 6. Inspect   12   valve   seat   inserts   (10)   for   cracks, pits,   and   excessive   wear.   Replace   damaged valve seat inserts (see step 7). NOTE Perform    step    7    only    if    valve    seat inserts are damaged. 7. Using valve seat puller, remove valve seat insert (10) from cylinder head (4). WARNING Dry cleaning solvent, P-D-680,  is  toxic  and  flammable.  Always  wear  protective  goggles  and  gloves,  and use only in a well-ventilated area. Avoid contact with skin, eyes, and clothes, and DO NOT breathe vapors. DO NOT use near open flame or excessive heat. The solvent's flash point is 100°F-138°F (38°C-59°C). If you  become  dizzy  while  using  cleaning  solvent,  immediately  get  fresh  air  and  medical  help.  If  solvent contacts eyes, immediately wash your eyes and get medical aid. 8.    Clean valve springs, valve spring retaining lock, and rotators with dry cleaning solvent and dry with clean rags. 9.    Inspect cylinder head valves and valve springs for damage. Replace damaged parts. 10.    Inspect rotators for proper movement. Rotators must turn freely in both directions. Replace defective rotators. 11.    Using spring tester and torque wrench, compress valve springs to 1.81 in. (4.60 cm) and note compression force on  torque  wrench.  Compression  force  must  be  54-62  lb.-ft.  (73-84  N.m).  Replace  valve  springs  not  within specification. 12.    Using spring tester and torque wrench, compress valve springs to 1.36 in. (3.45 cm) and note compression force on torque wrench. Compression force must be 133-135 lb.-ft. (180-183 Nom). Replace valve springs not within specification. TA708069 4-23