For 1990-2009 cars

# UNI-BODY COLLISION REPAIR PROCEDURES

THE FOLLOWING REPAIR PROCEDURES ARE TO ACQUAINT YOU WITH RECOMMENDED REPAIR GUIDELINES, BASED UPON CONCLUSIONS DRAWN FROM DURABILITY TESTING, FOR ALL UNIBODY CONSTRUCTED 1980-1982 CITATION AND 1982 CELEBRITY SERIES. 1.THE OXY-ACETYLENE TORCH CAN BE USED FOR HEATING AND WELDING OPERATIONS ON UNIBODY COMPONENTS (SEE TEMPERATURE LIMITATIONS IN #4 BELOW). WITH REGARD TO WELDING, ONLY MILD STEEL ROD SHOULD BE USED - NO BRAZING SHOULD BE ATTEMPTED. 2.SECTIONING OF THE ENGINE COMPARTMENT LOWER SIDE INNER RAIL IS A PRACTICAL REPAIR APPROACH USING A BUTT WELD JOINT. IT IS NECESSARY TO GRIND OFF THE GALVANIZED COATING IN THE AREA OF THE WELD JOINT (APPROXIMATELY 25MM EITHER SIDE) TO PREVENT ZINC CONTAMINATION OF THE WELD BEAD. SELECT AN AREA REARWARD OF THE DAMAGED AREA WHERE THE NEW RAIL SECTION CAN BE INDEXED TO THE EXISTING RAIL. AS AN EXAMPLE, THE REPLACEMENT INNER RAIL MAY BE TRIMMED APPROXIMATELY 50MM REARWARD OF THE 29MM HOLE . THE HOLE THEN SERVES TO INDEX THE NEW RAIL SECTION FOR ACCURATE TRANSFER OF THE CUT LINE TO THE EXISTING RAIL. 3.IF DAMAGE IS EXTENSIVE, ALL OTHER COMPONENTS, I.E. FRONT UPPER RAILS, FRONT LOWER OUTER RAILS, ENGINE COMPARTMENT SIDE PANEL AND ENGINE COMPARTMENT FRONT PANEL SHOULD BE REPLACED AS A COMPLETE ASSEMBLY. 4.DO NOT SECTION THE ENGINE COMPARTMENT LOWER SIDE INNER RAIL IF STRAIGHTENING IS A MORE PRACTICAL APPROACH. WHEN STRAIGHTENING IS THE SELECTED REPAIR METHOD, DO NOT APPLY TORCH HEAT BEYOND THE VERY DULL RED STAGE, (APPROXIMATELY 1200F-1400F). HEAT APPLIED AT THAT RANGE IS SUFFICIENT TO RELIEVE WORK HARDENING WITHOUT A DETRIMENTAL EFFECT UPON THE BASE METAL. 5.ALL WELDED AND/OR HEATED AREAS ARE TO BE THOROUGHLY CLEANED, PREFERABLY BY SAND BLASTING, FOLLOWED BY METAL CONDITIONING. PRIME WITH A CHROMATE PRIMER (DUPONT ACRYLIC CHROMATE PRIME (GREEN) 215S) OR EQUIVALENT TO PROTECT METAL SURFACES WHERE GALVANIZED SURFACES AND PRIMER COATING MAY HAVE BEEN BURNED BY GAS WELDING OPERATIONS. A UNIVERSAL TYPE PRIMER SURFACER SHOULD THEN BE APPLIED OVER THE CHROMATE PRIMER, FOLLOWING THE MANUFACTURERS' LABEL DIRECTIONS. ALL JOINTS SHOULD BE SEALED USING 3M ALL AROUND AUTOBODY SEALANT #8500 OR EQUIVALENT PRIOR TO COLOR APPLICATION. 6.THE INTERIOR SURFACE OF ALL BOXED SECTIONS, SUCH AS THE LOWER SIDE RAILS, AS WELL AS ALL REPAIRED AREAS AND SURFACES SHOULD BE COATED WITH AN ANTI-CORROSION COMPOUND TO PROVIDE CORROSION PROTECTION. SOME MATERIALS ESPECIALLY SUITED FOR THIS ARE "GUARD-MOR" PART NUMBER #1051685, 60 LITERS (16 GAL.) #1051686, 210 LITERS (55 GAL.); OR AN EQUIVALENT TYPE MATERIAL. USE A PROBE WAND TO OBTAIN FULL MATERIAL COVERAGE. 7.THE PROCEDURE ABOVE, RECOMMENDING OXY-ACETYLENE WELDING, DOES NOT PRECLUDE THE USE OF THE MIG WELDER FOR COMPONENT REPLACEMENT AND SECTIONING. 8.A COMPLETE COURSE COVERING SECTIONING AND REPAIR OF UNITIZED BODY CONSTRUCTION IS CURRENTLY OFFERED AT ALL GM TRAINING CENTERS UNDER FISHER BODY COURSE #22003.25.

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.