TM  10-3930-643-34 BRAKE  TROUBLESHOOTING  AND  MAINTENANCE.  (cont) 8-14. Air Compressor. (Sheet 7 of 13) CLEANING/INSPECTION   (cont) 34. Using a micrometer, measure front bearing journal (threaded end) of crankshaft (38). Dimension must be 1.3779 to 1.3784 inches. 35. Using a micrometer, measure rear bearing  journal  of  crankshaft  (38). Standard  dimension:  1.3779  to  1.3784 inches . 0.010  U/S  dimension:  1.3684  to  1.3689 inches. 0.020  U/S  dimension:  1.3584  to  1.3589 inches  . 0.030 U/S dimension: 1.3484 to 1.3489 inches  . NOTE If necessary, grind rear bearing journal to next lower undersize dimension  and  replace  bearing  cap with  appropriate  undersize  bearing cap. 36. Using a micrometer, measure two connecting  rod  bearing  journals. Standard  dimension:  1.1230  to  1.1235 inches. 0.020 U/S dimension: 1.1040 to 1.1035 inches. 0.030 U/S dimension: 1.0940 to 1.0935 inches. Go to sheet 8 8-68