Figure 3-26.–Removing or installing a piston pin bushing.When you insert new bushings, be sure that the boreinto which they are pressed is clean and that the oil holesin the bushing and the oil passages in the rod are aligned.To obtain proper clearance, sometimes you will need toream a piston pin bushing after it has been installed.Figure 3-27 shows equipment used to ream a bushing.After installing a new bushing, check the alignmentof the rod with equipment such as illustrated in figure3-28. Be sure to check the manufacturer’s technicalmanual for details concerning clearances and alignmentprocedures.INSPECTING, MAINTAINING, ANDREPAIRING CONNECTING RODSMost connecting rod troubles involve either theconnecting rod bearing or the piston pin bearing. Youcan avoid these troubles by performing propermaintenance procedures and by following instructionsin the manufacturer’s service manual. There are,however, certain unavoidable troubles, such as crackedconnecting rods caused by defective material. Suchcracks must be discovered before they develop to a pointthat the rod fails. Magniflux testing is considered thebest method for locating cracks. If you discover a crackin a connecting rod, replace the rod; do not try to repairit. If you have to replace a damaged rod, send it, withother damaged parts, to a salvage center for possiblereclamation.Do not repair defective connecting rod bolts, exceptfor removing small burrs by using a fine rectangular file.If you doubt the condition of a bolt or a nut, replace it.Check the connecting rod bore for out-of-roundnesswith an inside micrometer. Make the correction andrecheck the bore. If the distortion is permanent, replacethe rod.You can make plugged oil passages of connectingrods serviceable by running a wire through them. Inextreme cases, you may need to drill the passages freeof foreign matter.Figure 3-27.–Reaming equipment.3-18
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