SMU-SEC. 6A1 - SELECTION OF STANDARD MAIN BEARINGS. Geo Metro 1991

********************************************************************** SERVICE MANUAL UPDATE **********************************************************************

SUBJECT: SECTION 6A1 - SELECTION OF STANDARD MAIN BEARINGS

MODELS: 1989-94 GEO METRO

**1989-91 GEO METRO** THE INFORMATION CONTAINED IN THIS BULLETIN AMENDS STEP 1 AND STEP 4 OF PAGE 6A1-39 UNDER "SELECTION OF MAIN BEARINGS" "STANDARD BEARINGS" IN THE FOLLOWING SERVICE PUBLICATIONS:

1989 GEO METRO SERVICE MANUAL (ST370-89) 1990 GEO METRO SERVICE MANUAL (ST370-90) 1991 GEO METRO SERVICE MANUAL (ST370-91)

1. CHECK THE JOURNAL DIAMETER BY THE METHOD BELOW.

THE COUNTER WEIGHTS OF NO. 1 CYLINDER HAVE FOUR STAMPED NUMBERS. THE THREE NUMBERS CAN BE A ("1", "2", AND "3"). THE FIRST, SECOND, THIRD AND FOURTH (LEFT TO RIGHT) STAMPED NUMBERS INDICATE THE DIAMETERS AT BEARING CAP "1", "2", "3" AND "4" RESPECTIVELY. FOR EXAMPLE, THE FIRST (LEFTMOST) NUMBER "3" INDICATES THAT THE JOURNAL DIAMETER AT BEARING CAP "1" IS WITHIN 44.982 - 44.988 MM, AND THE SECOND NUMBER ("1") INDICATES THAT THE JOURNAL DIAMETER AT BEARING CAP "2" IS WITHIN 44.994 - 45.000 MM (FIGURE 133 FOR 1989 AND 1990 METRO OR FIGURE 131 FOR 1991 METRO).

4. FROM THE NUMBERS STAMPED ON THE COUNTER WEIGHTS OF NO. 1 CYLINDER AND THE LETTERS STAMPED ON THE MATING SURFACE OF THE CYLINDER BLOCK, DETERMINE THE NEW STANDARD BEARING TO BE INSTALLED ON THE JOURNAL BY REFERRING TO THE TABLE (FIGURE 136 FOR 1989 AND 1990 METRO OR FIGURE 134 FOR 1991 METRO). FOR EXAMPLE, IF THE NUMBER STAMPED ON THE COUNTER WEIGHT IS "1" AND THE LETTER STAMPED ON THE MATING SURFACE IS "B", INSTALL THE NEW STANDARD BEARING PAINTED WITH "BLACK" TO ITS JOURNAL.

**1992-94 GEO METRO**

THE INFORMATION CONTAINED IN THIS BULLETIN AMENDS STEP 4 ON PAGE 6A1-50 UNDER "SELECTION OF MAIN BEARINGS" "STANDARD BEARINGS" IN THE FOLLOWING SERVICE PUBLICATIONS:

1992 GEO METRO SERVICE MANUAL (ST370-92) 1993 GEO METRO SERVICE MANUAL (ST370-93) 1994 GEO METRO SERVICE MANUAL (ST370-94)

4. FROM THE NUMBERS STAMPED ON THE COUNTER WEIGHT OF NO. 1 CYLINDER AND THE LETTERS STAMPED ON THE MATING SURFACE OF THE CYLINDER BLOCK, DETERMINE NEW STANDARD BEARING TO BE INSTALLED ON THE JOURNAL BY REFERRING TO THE TABLE. FOR EXAMPLE, IF THE NUMBER STAMPED ON THE COUNTER WEIGHT IS "1" AND THE LETTER STAMPED ON THE MATING SURFACE IS "B", INSTALL THE NEW STANDARD MAIN BEARING WITH "BLACK" TO ITS JOURNAL.

FIGURES: 1 (ARTWORK IS FOR 1992-94 GEO METRO)

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.