TM 5-3805-260-24
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 oxen and get the
temperature of the rod to 400F (204°C).
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 pot assembly is in the center of the
piston pin bearing.
Install the pin for the large end of the connecting
rod In the center oft' 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 5P8641
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 hearing 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
.
3-383
