For 1990-2009 cars

# GAS SUPPORT ASSEMBLY EVALUATION AND REPLACEMENT

AN EVALUATION OF GAS SUPPORT ASSEMBLIES THAT WERE REPLACED FOR NOT HOLDING THE REAR COMPARTMENT LID OPEN INDICATES THAT SOME GOOD SUPPORTS HAVE BEEN ERRONEOUSLY REPLACED. THIS BULLETIN DISCUSSES THE POSSIBLE REASONS FOR THIS AND OUTLINES PROCEDURES FOR EVALUATING AND REPLACING QUESTIONABLE GAS SUPPORTS. GAS SUPPORT EVALUATION 1.ENSURE THAT THE PROPER GAS SUPPORT ASSEMBLY IS INSTALLED IN THE VEHICLE AND THAT REPLACEMENTS ARE THE ONES SPECIFIED IN THE PARTS LISTING. EACH GAS SUPPORT IS DESIGNED FOR A PARTICULAR COMPARTMENT LID. THE ATTACHMENT BRACKETS, STROKE LENGTH, GAS PRESSURE AND INTERNAL VALVING ARE SPECIFIED TO PROVIDE A CONTROLLED OPENING ASSISTANCE AND A HOLD OPEN FORCE. THE HOLD OPEN FORCE HAS TO BE CLOSELY REGULATED SO THAT IT MAY BE EASILY OVERCOME WHEN CLOSING THE COMPARTMENT LID. SUBSTITUTING SUPPORTS WITH ONES WITH HIGHER OPERATING PRESSURES IS NOT RECOMMENDED. THIS COULD CAUSE THE LID TO OPEN RAPIDLY AND REQUIRE EXTRA OPERATOR EFFORT TO CLOSE, PARTICULARLY IN A WARM ENVIRONMENT. 2.CHECK THAT THE GAS SUPPORT IS THE CAUSE OF THE LID NOT STAYING OPEN. IN EXTREMELY COLD TEMPERATURES (BELOW -29C (-20F)), IT IS NORMAL FOR THE GAS PRESSURE TO BE REDUCED AND THIS RESULTS IN A LESSENED HOLD OPEN FORCE UNTIL WARMER WEATHER OCCURS. AT THESE COLD TEMPERATURES, A SIGNIFICANT ACCUMULATION OF SNOW ON THE LID OR FROZEN WATER VAPOUR BETWEEN THE DECK LID PANELS WOULD AFFECT THE LID'S ABILITY TO HOLD OPEN. 3.USE A SYSTEMATIC REPLACEMENT PROCEDURE THAT ENSURES THAT ONLY DEFECTIVE GAS SUPPORTS ARE REPLACED. TESTING HAS INDICATED, THAT IN A NORMAL CLEAN ENVIRONMENT, GAS SUPPORTS DO NOT WEAR OUT IN PAIRS. THE MAJORITY OF FAILURES ARE DUE TO SEAL DEFECTS WHICH MAY BE CAUSED DURING INITIAL ASSEMBLY OR BY A ROUGH SHAFT. IN EITHER CASE, THE FAILURE OF ONE SUPPORT ASSEMBLY DOES NOT PREDICT ANYTHING ABOUT THE FUTURE LIFE OF THE OTHER ONE. TO RESTORE THE LID SUPPORT SYSTEM TO NORMAL IT IS ONLY NECESSARY TO LOCATE AND REPLACE THE FAILED SUPPORT AS PER THE SUBSTITUTION SEQUENCE NOTED BELOW. GAS SUPPORT REPLACEMENT PROCEDURE 1.AFTER DETERMINING THAT THE LID SUPPORT SYSTEM IS NOT FUNCTIONING PROPERLY, OBTAIN A CORRECT REPLACEMENT PART. 2.REPLACE A GAS SUPPORT ON ONE SIDE OF THE AFFECTED VEHICLE. 3A.LID STAYS UP - STOP 3B.LID FALLS DOWN 3-.REINSTALL, ON THE OTHER SIDE, THE SUPPORT REMOVED IN STEP 2. 4A.LID STAYS-UP - STOP 4B.LID FALLS DOWN 4-.REPLACE, WITH A NEW ASSEMBLY, THE SUPPORT INSTALLED IN STEP 3. 5A.LID STAYS-UP - STOP 5B.LID FALLS DOWN 5-.RETURN TO STEP 1. PARTS INFORMATION IF THE ATTACHMENT CLIPS BECOME LOST OR DAMAGED, REPLACEMENTS MAY BE OBTAINED THROUGH GM PARTS. RETAINING CLIP-DECK LID MODELS 20108168 RETAINING CLIP-HATCH & WAGON MODELS 20267501

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