ARMY TM 9-2815-256-24 AIR FORCE TO 38G1-96-2 MARINE CORPS TM 2815-24/5 FIGURE 3-91.  Measuring Roller-To-Roller Dimension r. Perform a centrality check as follows.  Maximum allowable tolerance is 0.004 inch (0.102 mm). (1) After setting roller-to-roller dimension, rotate rotor until one roller is aligned with dial indicator plunger.  Slide indicator inward until plunger depresses it at least 0.010 inch (0.25 mm).  Lock indicator retaining screw zero dial indicator on high Point of roller by rotating knurled dial. (2) Rotate rotor (either direction) until other roller depresses dial indicator plunger. (3) If roller centrality is beyond specified tolerance, roller and/or shoes can be interchanged.  Recheck centrality after each change and recheck roller-to-roller dimension. s. Rinse hydraulic head assembly in clean calibrating oil. t. Rest unit on weight retainer (33, FIGURE 3-73). NOTE If cam ring (24) is installed incorrectly, pump will not be in time with engine. u. Place  cam  ring  (24)  onto  rotor  assembly  with  directional  arrow  indicating  direction  of  pump  rotation.    (Pump rotation is as viewed from drive end.) v. Place hydraulic head on rotor. w. Position two rotor retainers (23) on head and rotor with cutout portions meeting over spring pin hole in hydraulic head. x. Position  liner  locating  ring  (22)  over  rotor  retainers  (23)  and  bottom  it  against  head.    Position  split  in  ring  90 degrees from split in retainers. NOTE Preformed packing (16) has an oval cross section and can be identified by rolling it between fingers. y. Install new Preformed packing (16) in groove on hydraulic head (17).  Be sure to push packing all the way into its groove. z. Install liner (15) so slot is lined up with hole in which regulator assembly roll pin (12) enters. 3-110