STEERING WANDER OR STEERING PULL

SUBJECT: STEERING WANDER OR STEERING PULL (SET CORRECT COMPONENT SPECIFICATIONS AND LOAD VEHICLE PROPERLY)

MODELS: 1992-1995 P CHASSIS MOTOR HOME 14,500 GVW AND ABOVE

CONDITION:

SOME OWNERS MAY COMMENT OF STEERING WANDER OR STEERING PULL.

CAUSE:

THE CAUSE OF THE STEERING WANDER MAY BE THE RESULT OF INCORRECT TRIM HEIGHT, INCORRECT FRONT END ALIGNMENT, EXCESSIVE PLAY IN THE STEERING SYSTEM, IMPROPER TIRE PRESSURE AND IMPROPER WEIGHT DISTRIBUTION OF PAYLOAD WITHIN THE MOTOR HOME.

CORRECTION:

COMMENTS OF STEERING WANDER OR STEERING PULL MAY BE DIAGNOSED USING THE FOLLOWING DIAGNOSTIC PROCEDURES TO INSURE THE VEHICLE COMPONENTS ARE SET TO THE CORRECT SPECIFICATIONS AND THE VEHICLE IS LOADED PROPERLY.

NOTICE: REFER TO THE END OF THIS BULLETIN FOR LABOR OPERATIONS AND LABOR HOURS FOR DIAGNOSTIC PROCEDURES.

DIAGNOSTIC PROCEDURE 1 - CHECK THE FOLLOWING:

1. TIRE PRESSURE. CHECK THE TIRE PRESSURE AND COMPARE THE RECOMMENDED SPECIFICATION TO THE GVW LABEL IN THE MOTOR HOME. ADJUST THE PRESSURE TO THE SPECIFICATION AS REQUIRED. CARE SHOULD BE TAKEN TO INSURE THE TIRE PRESSURE IS EQUAL BETWEEN THE RIGHT AND LEFT SIDE OF THE VEHICLE. IMPROPER TIRE INFLATION CAN AFFECT RIDE AND HANDLING.

2. VEHICLE LOAD CONDITIONS. UNUSUAL LOAD CONDITIONS CAN AFFECT THE RIDE AND HANDLING OF THE VEHICLE. CHECK THE DISTRIBUTION OF THE PAYLOAD WITHIN THE VEHICLE. IF THE LOAD IS ALL TOWARD THE EXTREME REAR OF THE VEHICLE OR TOWARD ONE SIDE, REPOSITION THE LOAD AS REQUIRED TO OBTAIN A MORE UNIFORM WEIGHT DISTRIBUTION. THE ONLY WAY TO BE SURE TO AVOID AN OVERLOAD CONDITION IS TO ADVISE THE CUSTOMER TO WEIGH THE MOTOR HOME. REFERENCE APPENDIX I FOR COMPLETE INSTRUCTIONS FOR PROPERLY WEIGHING A MOTOR HOME.

3. FRONT SUSPENSION AIR BAG CYLINDER PRESSURE. IT IS IMPORTANT THE CYLINDERS BE INFLATED TO THE PROPER PRESSURE FOR THE LOAD BEING CARRIED IN ORDER TO MAINTAIN ADEQUATE RIDE HEIGHT. ADJUST AIR BAG CYLINDER PRESSURE SO THE MEASUREMENT BETWEEN THE BRACKET AND CROSS MEMBER FLANGE, THE "BC" DIMENSION IS 3.00 +/- 0.250 INCHES. REFERENCE FIGURE 1 FOR DETERMINING RIDE HEIGHT MEASUREMENT.

4. FRONT END ALIGNMENT. CHECK THE FRONT END ALIGNMENT FOR PROPER SETTING. REFERENCE SECTION 3A, FRONT WHEEL ALIGNMENT OF THE P3 SERVICE MANUAL. IF REQUIRED, SET THE WHEEL ALIGNMENT TO THE FOLLOWING SPECIFICATIONS.

CAMBER: 0.25 DEGREE +/- 0.25 DEGREE CASTER: 5.0 DEGREE +/- 0.5 DEGREE SUM TOE-IN: 0.00 TO 0.03 IN. OR 0.0 TO 0.06 DEGREE

IMPORTANT: THE CASTER, CAMBER, AND TOE-IN DIMENSIONS ARE DETERMINED FOR THE VEHICLE AT DESIGN LOAD AND WITH THE FRAME LEVEL. THE NORMAL FRAME ANGLE MUST BE CONSIDERED WHEN USING THE ALIGNMENT EQUIPMENT. THIS IS ESPECIALLY IMPORTANT WHEN MAKING THE CASTER ANGLE CHECK TO OBTAIN A TRUE OR CORRECTED SETTING.

5. TEST DRIVE VEHICLE. AFTER PERFORMING DIAGNOSTICS STEPS 1 - 4 AND IF ADJUSTMENTS WERE REQUIRED, IT IS RECOMMENDED THE MOTOR HOME BE TEST DRIVEN BEFORE PROCEEDING FURTHER. GENERALLY, IT HAS BEEN FOUND THAT MOST STEERING CONTROL CONCERNS WILL BE CORRECTED BY PERFORMING THE ABOVE PROCEDURES. IF A STEERING CONCERN STILL EXISTS, CONTINUE TO THE STEERING SYSTEM ADJUSTMENT.

DIAGNOSTIC PROCEDURE 2 - STEERING SYSTEM

IDLER ARM FREE PLAY

CHECK THE FREE PLAY OF THE IDLER ARMS. REFERENCE STEERING LINKAGE, SECTION 3B3 OF THE P3 CHASSIS SERVICE MANUAL. IF NECESSARY, ADJUST THE IDLER ARM SUPPORT SHAFT END PLAY.

STEERING GEAR FREE PLAY

1. REFERENCE GENERAL INFORMATION, SECTION 0A OF THE P3 CHASSIS SERVICE MANUAL FOR GENERAL VEHICLE LIFTING AND JACKING PROCEDURES.

RAISE THE FRONT OF THE VEHICLE SO THE FRONT WHEELS ARE OFF THE GROUND.

2. DISCONNECT THE DRAG LINK AT THE PITMAN ARM. REFERENCE POWER STEERING GEAR AND PUMP, SECTION 3B AND STEERING LINKAGE, SECTION 3B OF THE P3 CHASSIS SERVICE MANUAL.

3. TURN THE IGNITION KEY TO THE UNLOCK POSITION SO THE STEERING WHEEL IS FREE TO MOVE.

4. WITH THE STEERING WHEEL ON CENTER; THAT IS, THE FRONT TIRES MUST NOT BE TURNED RIGHT OR LEFT, BUT POINTED STRAIGHT AHEAD; ROCK THE PITMAN ARM FORE AND AFT TO DETERMINE ANY LASH OR FREE- PLAY.

IF FREE-PLAY IS PRESENT, ADJUST THE STEERING GEAR AS FOLLOWS:

LOOSEN THE LASH ADJUSTER AND TURN THE LASH ADJUSTER SCREW CLOCKWISE UNTIL ALL THE FREE-PLAY IS REMOVED (1/4-3/4 TURN), TIGHTEN THE LASH ADJUSTER NUT.

IMPORTANT: DO NOT OVER-TIGHTEN THE LASH ADJUSTER SCREW AS INCREASED STEERING EFFORT AND POOR STEERING WHEEL RETURN ABILITY COULD RESULT.

5. RECONNECT THE DRAG LINK TO PITMAN ARM.

6. LUBRICATE ALL STEERING AND SUSPENSION BALL JOINTS

DIAGNOSTIC PROCEDURE 1:

LABOR OPERATION NO. T-2710

LABOR HOURS: 1.1 HRS.

ADD: ADJUST ALIGNMENT 0.6 HRS.

DIAGNOSTIC PROCEDURE 2:

LABOR OPERATION NO. T-2711

LABOR HOURS: 0.6

ADD: ADJUST IDLER ARM FREE PLAY 0.1

ADD: ADJUST STEERING GEAR FREE PLAY 0.2

APPENDIX 1

WEIGHING THE MOTOR HOME

THE ONLY WAY TO BE SURE TO AVOID AN OVERLOAD CONDITION IS TO WEIGH THE MOTOR HOME. TO DO SO ACCURATELY, THE MOTOR HOME OWNER NEEDS TO FIND A SCALE THAT HAS A LEVEL AREA ON THE SIDE, AND TO DEVELOP AN EXCELLENT RAPPORT WITH THE PERSON DOING THE WEIGHING. THE LEVEL SIDE AREA IS VERY IMPORTANT, BECAUSE IT WILL BE NECESSARY TO HAVE 50 PERCENT OF THE LEFT AND RIGHT SIDES OF THE COACH OFF THE SCALE DURING SOME OF THE WEIGHING. IF THE SIDE AREA IS NOT LEVEL, THE SIDE WEIGHTS WILL BE INCORRECT. SUITABLE SCALES MIGHT BE FOUND AT TRUCK STOPS, SAND AND GRAVEL PIT OPERATIONS AND MOVING COMPANIES.

PROVIDE THE MOTOR HOME OWNER WITH A PHOTOCOPY OF THE COACH WEIGHING WORKSHEET THAT ACCOMPANIES THIS APPENDIX FOR USE AS A REFERENCE AT THE SCALE. WEIGH THE MOTOR HOME AT AN OFF TIME, SINCE THE ENTIRE PROCESS CAN TAKE UP TO ONE-HALF HOUR. BEFORE WEIGHING THE MOTOR HOME, IT SHOULD BE LOADED NORMALLY FOR TRAVEL, INCLUDING FOOD, CLOTHING, FUEL, WATER, PROPANE, ETC.

THE WORKSHEET DIVIDES THE MOTOR HOME INTO FOUR SECTIONS. THIS IS DONE BY FINDING THE HALFWAY POINT BETWEEN THE FRONT AND REAR TIRES (AXLES) AND THE HALFWAY POINT BETWEEN THE FRONT TIRES AND THEN THE HALFWAY POINT BETWEEN THE REAR TIRES. DO NOT SIMPLY USE THE DISTANCE BETWEEN THE FRONT AND REAR OF THE BODY; BE SURE TO USE THE AXLES AS A REFERENCE POINT. USE TAPE TO MARK THE SIDE- TO-SIDE HALFWAY POINTS ON THE FRONT BUMPER AND ON THE REAR BUMPER TO MAKE THE REFERENCE POINTS EASILY VISIBLE. DO THE SAME FOR THE FRONT-TO-REAR HALFWAY POINTS BY APPLYING TAPE TO THE SIDE OF THE MOTOR HOME. DRIVE THE MOTOR HOME ONTO THE SCALE TO THE POINT THAT THE FRONT-TO-REAR TAPE PIECES INDICATE THAT ONE-HALF OF THE WHEEL BASE IS ON THE SCALE AND ONE-HALF IS OFF. REFERRING TO THE WORKSHEET, THIS WILL BE WEIGHT NUMBER W1.

NEXT, DRIVE THE ENTIRE MOTOR HOME ONTO THE SCALE. THIS WILL BE WEIGHT NUMBER W2. THEN DRIVE OFF THE SCALE SO THAT THE SIDE TAPE STRIPE INDICATES THAT THE REAR HALF OF THE CHASSIS REMAINS ON. THIS WILL BE WEIGHT W3. IT IS IMPORTANT THAT ONE-HALF OF THE CHASSIS, NOT THE MOTOR HOME, RESTS ON THE SCALE DURING WEIGHING.

WEIGHT NUMBER W1 SHOULD NOT EXCEED THE GAWR FOR THE FRONT AXLE. WEIGHT NUMBER W2 SHOULD NOT EXCEED THE TOTAL GVWR. WEIGHT NUMBER W3 SHOULD NOT EXCEED THE REAR AXLE GAWR.

TO MAKE THE WEIGHTS MORE MEANINGFUL, USE THE SIDE-TO-SIDE AND FRONT-TO-REAR TAPE PIECES TO DIVIDE THE CHASSIS UP INTO QUARTERS AND THEN WEIGH EACH SECTION: FRONT LEFT, WEIGHT ZONE W4; REAR LEFT, WEIGHT ZONE W6; FRONT RIGHT, WEIGHT ZONE W5, AND FINALLY REAR RIGHT, WEIGHT ZONE W7. THE WEIGHTS FOR ZONE W4 AND ZONE W5 SHOULD BE ABOUT EQUAL, AS SHOULD THE WEIGHTS FOR ZONES W6 AND W7. IF THIS IS NOT THE CASE, TRY TO MOVE ITEMS INSIDE THE MOTOR HOME TO BRING THE WEIGHTS CLOSE.

WHEN COMPARING THE TOTAL WEIGHT OF THE TWO FRONT QUARTERS TO THE TOTAL AXLE WEIGHT, THE FIGURES PROBABLY WILL NOT BE EXACTLY EQUAL, BUT THEY SHOULD BE CLOSE. THE SAME APPLIES TO THE REAR AXLE. IT IS ALSO POSSIBLE THAT THE FRONT AND REAR GAWR WHEN TOTALED WILL BE MORE THAN THE GVWR. THIS IS BECAUSE THE LIMITING FACTOR MAY BE SOMETHING SUCH AS THE TRANSMISSION PARKING PAWL, BRAKING CAPACITY, OR ANOTHER COMPONENT.

IN ORDER TO PROPERLY DETERMINE THE WEIGHT OF THE VEHICLE, START WITH THE WEIGHT THAT WOULD NORMALLY BE CARRIED WHEN TRAVELING. IF THE WEIGHT PLACES THE VEHICLE OVER THE GVWR, REMOVE SOME WEIGHT AND WEIGH THE MOTOR HOME AGAIN. WEIGHT AND WEIGHT DISTRIBUTION IS IMPORTANT TO THE SAFE OPERATION OF THE VEHICLE AND THE VEHICLE'S OVERALL SERVICE LIFE.

FIGURES: 2

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.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.