3208 INDUSTRIAL ENGINE Caterpillar


Connecting Rods

Usage:

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 (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 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 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 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 The allowable difference for rods that are acceptable for reconditioning is ± .004 in.

Leave the connecting rod in the checking fixture and check for both bores parallel. Make a record of the readings for both dial indicators. The total difference between indicator readings is the bores parallel dimension. The maximum allowable dimension is .006 in. for rods that are acceptable for reconditioning.

A check can also be made to check for connecting rod twist. Push one end of the pin mandrel against the locating surface behind it. Use a thickness gauge on the opposite end to check the clearance between the mandrel and the locating surface. Check both ends of the mandrel in this way for clearance. The amount of clearance is the twist in the rod. The maximum allowable twist is .012 in. for rods that are acceptable for reconditioning.

Boring Piston Pin Bearing

After new piston pin bearings are installed in the connecting rods, use the 5P3550 Connecting Rod Boring Machine to bore the piston pin bearings to the correct size.

Install the cap on the connecting rod (do not install the bearings). Tighten the nuts as shown in the SPECIFICATIONS.

Put the 5P2010 Mandrel on the spindle. Install nut and actuator, and tighten to hold mandrel in position. Install 5P2013 Plunger Extension on the plunger. The plunger must be in the up position within ± 3°. Loosen the spindle carrier, and use the handle on top to adjust the bearing bore center-to-center dimension. Move the carrier until the vernier scale reads 7.6867 ± .0010 in. This is the correct scale dimension to get a bearing bore center-to-center dimension of 7.9000 ± .0010 in. Tighten the carrier in this position.

Put the connecting rod in position on the mandrel, with the boss on the pin end of the rod towards the left. Turn the actuator until the connecting rod is tight on the mandrel.

Install 5P3552 Bushing in the front bracket. Push the locating arbor through the front bushing. Put 5P3541 Locating Bushing, with the large dimension of the diamond shape horizontal, on the locating arbor. Slide the locating arbor through the connecting rod and into the rear bushing. Slide the locating bushing into the rod. Push the locating rods until they are against the connecting rod, and tighten the rods firmly. Remove the locating arbor end bushing.

Fasten the 5P2023 Tool Bit Setting Gauge to the boring bar. Be sure the contact point of the indicator is against the boring bar. Adjust the indicator so the revolution counter and the hand are at zero. Move the tool bit setting gauge so that the contact point is against the cutting edge of the tool bit. Fasten the gauge in this position. Loosen the screw that holds the tool bit. Make an adjustment to the tool bit until the indicator reads .1881 in. Tighten the screw that holds the tool bit and recheck the setting.

Put the boring bar through the connecting rod and into the rear bushing. Install the front bushing over the boring bar and into the bracket. Install 5P4777 Torsion Bracket on the rear of the boring machine. Put 5P4778 Feed Cylinder so the shaft goes through the rear bushing and into the boring bar. Tighten the setscrew in the boring bar to hold the feed cylinder shaft. Adjust torsion bracket and feed cylinder so the boring bar moves smoothly in rear bushing.

NOTE: Put the feed lever on the feed cylinder in the OPEN position before moving the boring bar.

With the feed lever in the OPEN position, move the boring bar until the tool bit is .125 in. (3.2 mm) from the bearing in the connecting rod. Put the feed lever in the CLOSED position and tighten the thumbscrew on the cylinder against the torsion bracket shaft. Install 5P2055 Flexible Adapter in the front of the boring bar and fasten an electric drill to the adapter. Put oil on the boring bar at the front and rear bushings. Start the drill and let the feed cylinder pull the boring bar through the bearing. Use a slow feed rate and do not push on the drill.

Check the bearing bore with a new piston pin. If the fit is too tight, do the boring operation again with the SAME tool bit setting.

Install the connecting rod into the piston with the boss on the rod on the same side as the crater in the piston.


CONNECTING ROD AND PISTON

When the connecting rod and piston assembly is installed, use new connecting rod bolt nuts.

Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.