ARMY TM 9-2815-254-24 AIRFORCE  TO  38G1-94-2 SECTION  III.  GENERAL  MAINTENANCE 3 - 3 . GENERAL This section provides general maintenance not found in other sections of Chapter 3. 3-3.1 General    Instructions. Where  applicable,    prior  to  performing  engine  maintenance,  ensure  bat- teries are disconnecting. Failure to observe this warning could results in severe  injury  or  death. Refer  to  end  item  maintenance  manual  for  removal  of  any  components necessary  to  gain  access  to  engine. It  is  strongly  recommended  that  bolts  or  nuts  securing  cylinder  heads,  covers,  and  doors  be  tightened  in  prop- er   sequence. a b. C. d. e. f. g. h. i. j. k. I. m. n. When   assembling   an   engine,   it   is   always   advisable   nuts,   bolts,   and   lockwashers   that   have   been removed from high strsss locations, in particular nuts an&or bolts from connecting rods and cylinder heads should be replaced. When assembling an engine it is always advisable to apply a small quantity of new engine lubricating oil (MIL-L-2104) to all moving parts. After any maintenance work on engine has bean completed, lubricating oil and fuel levels must be checked and all safety guards installed before operating. When a new fan drive belt has been installed, check belt tension after first 20 hours of operation. Wear protective overalls, and keep items of loose clothing dear of all hot and moving pans. Use protective barrier cream when necessary. Whenever possible, dean components and surrounding area before removing or disassembling. Take care to exclude all dirt and debris from fuel injection equipment while it is being serviced. Some parts are cemented with gasket compound with others being dry. Before assembly, remove all traces of old gasket and compound. Take extreme care to exclude dirt from all gasket surfaces and gasket com- pound from all tapped holes unless otherwise specified. It is recommended that all oil seals are replaced once they have been removed from their original position. Seals must be installed square in housing and all lip seals must be installed with lip facing lubricant to be re- tained. A service tool should be used to install all oil seals and care must be taken to prevent damaging new seal when it passes over shafts. Replace ail nuts, bolts, capscrews, and studs with damaged threads. Do not use a tap-or die to repair dam- aged threads which may impair the strength and closeness of the threads and is not recommended. Do not allow grease or oil to enter a blind threaded hole as hydraulic action present when bolt or stud is screwed in could split or stress housing. To  check  or  re-torque  a  bolt  or  nut,  item  is  slackened  a  quarter  of  a  turn  and  then  tightened  to  specified  value. A steel ISO metric bolt, capscrew, or nut can be identified by the letter M either on head or one hexagon flat. The strength grade will also be marked on top or one flat. On nuts with identification marks on one face the frictional area of that surface will be reduced, therefore nut should be installed with unmarked face towards component. Service took are designed to aid disassembly and assembly procedures and their use will prevent possible unnecessary  damage  to  components.  It  is  recommended  that  service  tools  are  always  used,  some  operations cannot be safely carried out without aid of reIevant tooI. 3-4. DISASSEMBLY  AND  ASSEMBLY  SEQUENCE  FOR  OVERHAUL. The following paragraphs provide the sequence of disassembly and assembly for complete overhaul of the en- gine. Step-by-step procedures can be found in remaining sections of Chapter 3. 3 - 1 2    C h a n g e    1