TM 10-3930-660-34 3-9.  CRANKSHAFT MAIN BEARINGS - REPLACE (Cont’d) 7. INSTALL NUMBER 1 AND NUMBER 7 MAIN BEARINGS (3 AND 4). a. Install  number  1  main  bearing  (3  and  4), STEPS 3a through 3e. CAUTION Be very careful not to scratch the crankshaft or the bearing bore during the installation of the   upper   bearing   half.      A   scratched   or damaged crankshaft, or bearing bore, could result in premature engine failure. b. To   insert   upper   half   of   number   1   main bearing   into   bearing   bore,   simultaneously push the upper bearing half with a flat blade screwdriver   and   turn   the   crankshaft   until bearing tab is in notch in cylinder block. c. Continue with number 1 bearing installation, STEPS 3i, 3j, and 3m through 30. 8. CHECK CRANKSHAFT ROTATION. Crankshaft  must  turn  freely.    If  it  does  not  turn with   relative   ease,   check   bearing   installations and size of bearings. 9. CHECK CRANKSHAFT END PLAY, PARA. 3-8, STEP 4. 10. INSTALL OIL SUCTION TUBE, PARA. 3-21. 11. INSTALL OIL PAN, PARA.  3-20. 3-79