TM 5-3825-226-24 CONNECTING RODS PISTON PIN BEARING REMOVAL AND INSTALLATION The 5P8639 Press Group and the 5P9705 Tool Group are used to remove and install the piston pin bearings in the connecting rods.  Use the procedure that follows to remove   and   install   the   piston   pin   bearing   from   the connecting rod. Remove  the  crankshaft  bearing  from  the  large  end  of the connecting rod and install the cap on the rod. Put   the   connecting   rod   in   an   oven   and   get   the temperature of the rod to 400°F (2040C). Put the 5P9704 Spacer in the counterbore of the base plate.  Be sure the spacer is in the bore straight and is against    the    bottom    of    the    counterbore.        Put    the connecting  rod,  with  the  Part  Number  up,  on  the  base plate  so  that  the  post  assembly  is  in  the  center  of  the piston pin bearing. Install the pin for the large end of the connecting rod in   the   center   of   the   bearing   bore.      Put   the   5P8653 Adapter over the post assembly and into the piston pin bearing.  Make sure the alignment hole in the adapter is in line with the hole in the base plate.  Install the 5P864 I1 Clamp Bar and the clamp pin on the large end of the connecting  rod.    Put  a  new  piston  pin  bearing  on  the 5P8653 Adapter. The bearing joint must be in alignment with the hole in the  adapter.    Put  the  5P8645  Push  adapter,  with  the tapered side down, on the post assembly and on top of the  5P8653  Adapter.    Make  sure  the  alignment  hole  in the  push  adapter  is  in  alignment  with  the  bearing  joint and the holes in the 5P8653 Adapter and the base plate. Put the pusher on the 5P8645 Push Adapter and use the   press   to   push   the   old   bearing   out   and   the   new bearing in.  Use the press until the push adapter makes full contact with the connecting rod.  Remove the tools and the connecting rod from the press group. NOTE:        The    piston    pin    bearing    must    be    bored (machined  to  size)  before  the  connecting  rod  can  be used. CHECK FOR CONNECTING ROD DISTORTION The 5P2050 Connecting Rod Checking Fixture is used to check for bearing bore center-to-center distance and for  piston  pin  bearing  bore  to  crankshaft  bearing  bore alignment.    The  checking  fixture  can  be  used  to  check connecting  rods  with  or  without  the  piston  pin  bearing installed. To check connecting rods that are to be reconditioned, the  fixture  must  first  be  adjusted  to  the  correct  bearing bore center-to-center distance.  Use a connecting rod of known length (master rod) for adjustment. Remove the connecting rod bearing and install the cap on the connecting rod and tighten the nuts as shown in the SPECIFICATIONS.  Remove the piston pin bearing from the connecting rod. Put  the  5P2041  Pin  Mandrel  in  the  piston  pin  end  of the  master  rod.    Install  the  5P2013  Plunger  Extension on the plunger of the 5P2053 Crank Mandrel.  Install the 5P2051 Position Arm on the end of the crank mandrel. Put the crank mandrel in the crankshaft bearing bore of the   master   rod.      Move   the   position   arm   so   it   is   in alignment  with  the  centerline  of  the  pin  mandrel.    Turn the actuator knob on the end of the crank mandrel and tighten the mandrel in the rod. Put the master connecting rod on the checking fixture. Move the dial indicator holder until both indicators show approximately    .010    in.        less    than    one    complete revolution.  Turn the dial face of each indicator until the hand is on zero. Remove the connecting rod from the fixture; turn the rod   180°   horizontally   and   put   the   rod   on   the   fixture again.    If  the  dial  indicators  read  zero,  the  fixture  is adjusted correctly.  If there is a different reading on the dial indicators, move the dial face one-half the distance between zero and the reading.  Remove the master rod from  the  fixture  and  remove  mandrels  from  the  master rod. The    checking    fixture    is    now    adjusted    to    check connecting rods for reconditioning. Use  the  procedure  that  follows  to  inspect  connecting rods to check if they are acceptable for reconditioning. Remove  the  connecting  rod  bearing  and  install  the cap on the connecting rod and tighten the nuts as shown in   the   SPECIFICATIONS.      Remove   the   piston   pin bearing from the connecting rod. Put the 5P2041 Pin Mandrel in the piston pin bearing bore.      Put   the   5P2053   Crank   Mandrel   with   5P2013 Plunger   Extension   and   5P2501   Position   Arm   in   the crankshaft   bearing   bore.      Move   the   position   arm   in alignment  with  the  centerline  of  the  pin  mandrel.    Turn the actuator knob on the crank mandrel and tighten the mandrel in the rod. Put the connecting rod on the checking fixture.  Make a  record  of  the  readings  on  each  of  the  dial  indicators. Add  the  two  readings  and  divide  by  two.    The  result  is the  average  difference  from  the  master  connecting  rod bearing  bore  center-to-center  distance.    The  allowable difference for rods that are acceptable for reconditioning is ±.004 in. 3-381