COVER 2P5818 - Caterpillar

Caterpillar: Confidential Yellow
VERIFICATION AND HANDLING OF MAIN BEARING FAILURES CAUSED BY ELECTRICAL DISCHARGE PITTING - SENT TO TEPS TRUCK DEALERS - NOT SENT TO COSA
  The information supplied in this service letter may not be valid after the termination date of this program.   Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
VERIFICATION AND HANDLING OF MAIN BEARING FAILURES CAUSED BY ELECTRICAL DISCHARGE PITTING 3208 Truck, Industrial, Marine Engines, 1202, 1203, 1400, 1405 U-36 A-32 AU-29 B-14 C-35 E-31 TT-5 Problem Main bearing failures caused by electrical discharge pitting (EDP) are NOT covered by the Caterpillar engine warranty. These failures are the result of inadequate electrical grounding of the engine and are not caused by defective materials or workmanship. Such failures are the responsibility of the user or the OEM (Original Equipment Manufacturer) which installed the engine. How to detect EDP failures is described in the June 23, 1982 Truck Engine News and June 21, 1982 Service Magazine. That article is attached for reference. Although the article is indicated for 3208 Truck Engines, the information applies to 3208 Engines in all applications. There is also available a Special Publication, "Analyzing Electrical Discharge Damage", SEBD0610. This publication contains detailed information and photos. It is listed in the March 15, 1983 Preview. Use this special publication as a supplement for "Engine Bearings and Crankshafts", SEBD0531, Section 3, "Failure Analysis for Main and Connecting Rod Bearings". When EDP is diagnosed as the cause of failure, the repairing dealer or user should contact the OEM representative or the OEM directly. Do not file a claim with Caterpillar. Improper grounding is the responsibility of the OEM or the user. Solution Proper electrical grounding of the engine to the vehicle frame is required as described in the attached article. As discussed in the article, a ground strap from the starter to the vehicle frame is NOT adequate because many starters are not electrically grounded to the engine due to internal electrical insulation systems in the starter. Reporting Whenever electrical discharge pitting (EDP) is encountered, submit a SIMS report. Report the failure as follows: Part number causing failure (USE MAIN BEARING PART NUMBER). Group number (use crankshaft group number) or use substitute group number 1202, which is SMCS code for crankshaft. Description Code "B". Under Optional Comments, print "Electrical Pitting". See following SIMS example. 1/830505/01/001 Engine Ground Straps Necessary to Prevent Electrical Discharge Damage To Crankshaft Bearings 1202, 1203, 1400, 1405 All 3208 Truck Engines Caterpillar's specifications say that engine-to-frame ground straps must be used on all truck engine installations. Engine component damage is possible if an acceptable engine-to-frame ground stap is not part of the vehicle's electrical system. On some installations, one of the alternator's electrical connections is made directly to an engine component such as a cylinder head or the cylinder block. If that component does not have a ground strap to the vehicle