CAMPAIGN: REAR AXLE WHEEL BEARING SEIZURE
SUBJECT: REAR AXLE WHEEL BEARING SEIZURES
MODELS: 1991 W7 GMC FORWARD - CHEVROLET TILTMASTER TRUCKS
The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle which is subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to adequately repair within 60 days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time.
If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonably equivalent vehicle at no charge, or to a refund of the purchase price less a reasonable allowance for depreciation.
To avoid having to provide these burdensome solutions, every effort must be made to promptly schedule appointments with owners and to repair their vehicles as soon as possible. As you will see in reading the attached copy of the letter which is being sent to owners, the owner is being instructed to contact the nearest GMC Zone Office if the dealer does not remedy the condition within five days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed how to contact the National Highway Traffic Safety Administration.
DEFECT INVOLVED
General Motors has learned that certain 1991 W7 GMC Forward - Chevrolet Tiltmaster vehicles have defective rear axle wheel bearings. These wheel bearings have improperly machined inner races which can cause excessive friction under some operating loads, resulting in seizure of either the inner or outer bearing at very low mileage. This bearing seizure can cause noise, possible rear wheel lockup, or possible rear wheel separation. If lockup or separation occurs while the vehicle is in motion, a vehicle crash could occur without prior warning.
To correct this condition, dealers will replace the inner and outer bearings and oil seals on both sides of the rear axle.
VEHICLES INVOLVED
Involved are certain 1991 W7 Forward - Chevrolet Tiltmaster vehicles built within the following VIN breakpoints:
MODEL MAKE FROM THROUGH YEAR ----- ------- -------- --------- 1991 GMC M3200004 M3200722 CHEVROLET M3200012 M3200645
The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin.
DEALER CAMPAIGN RESPONSIBILITY
Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Dealers are to correct all affected vehicles in new and used vehicle stock prior to their sale.
Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service in the future, you should take the steps necessary to ensure the campaign correction has been made before reselling or releasing the vehicle.
Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer and arrangements made to make the required cor- rection according to instructions contained in this bulletin.
If the name and address of the owner of an involved vehicle was unavailable to GMC Truck Division at the time of campaign initiation, the dealer must determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.
GMC Truck Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170
OWNER NOTIFICATION
Owners will be notified of this campaign on their vehicles by GMC Truck Division (see copy of owner letter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing may contain owner names and addresses obtained from State Motor Vehicle Registration records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to this campaign.
SERVICE PROCEDURE
CAUTION:
If any wheel experiences damage to a single stud caused by a loose-running wheel, all studs should be replaced. A loose-running wheel may cause only one stud to break, but the other studs could be internally fatigued to the point of being damaged. Replacing only the broken stud and remounting the wheel may cause further damage and personal injury. If the stud holes in the wheels have become larger in size or distorted, replace the wheel.
REQUIRED TOOLS & EQUIPMENT
98.4 mm (3.875 inch) Hex Bearing Nut Wrench J 4871, Three-Leg Bar Type Puller J 34577, Rear Wheel Hub Puller Pilot J 34913, Tension Scale Wheel Dolly Standard Screwdriver Solvent & Brush Mild Steel Drift
REMOVAL (Refer to Figure 2)
1. Raise the rear axle and place jack stand under the frame. Vehicle wheels must be off the floor.
2. Remove wheels from the hub (74) using a wheel dolly (see Figure 3).
3. Remove axle shaft (82).
4. Remove outer oil seal (81) from the hub (74).
5. Remove bolt (80) and washer (79), then nut (78) (use wrench in Figure 4) and outer bearing (77).
6. Remove hub (74) using J 4871 and J 34577 (see Figure 5).
7. Remove ring (69) from the hub (74), and use a screwdriver to remove seal (70).
8. Remove inner seal (70) and inner beating (71) from the hub (74).
9. Remove bearing cup (outer ring) from the hub (74) using a drift.
10. Clean axle housing end (65) and hub (74) using a solvent and brush.
INSTALLATION OF NEW REAR WHEEL INNER/OUTER BEARINGS (Refer to Figure 2) -----------------------------------------------------------------------
1. Install new bearing cups (outer rings) using a mild steel drift to drive them in.
2. Pack the new inner bearing (71) with NLGI No. 2 or 3 multi-purpose type grease or equivalent and install in the hub (74).
3. Install new inner seal (70) with the lip outward and snap ring (69) into the hub (74).
4. Fill the hub (74) with a 990g (2.18 lbs) grease NLGI No. 2 or 3 multi-purpose type or equivalent and install.
5. Pack the new outer bearing (77) with grease NLGI No. 2 or 3 multi-purpose type or equivalent and install.
6. Initially install nut (78) to zero torque so hub (74) spins freely, then tighten nut (78) using J 34913 to obtain bearing preload specification of 67 N (1 5 lbs) (see Figure 6).
7. Install new outer oil seal (81) with the lip outward and slip in axle shaft (82).
8. Install wheels on the hub (74) using a wheel dolly: make sure to tighten stud nuts finger tight first, then torque stud nuts to 465 N-m (345 ft.lbs) in sequence as in Figure 7.
9. Remove the jack stands and lower the vehicle.
10. Install "Campaign identification Label".
PARTS INFORMATION
Parts should be ordered directly from Isuzu Parts Distribution Network (AIPDN). Parts may also be obtained from General Motors Service Parts Opera- tion (GMSPO) on an order type ISC.
PART NUMBER DESCRIPTION QUANTITY ------- ------------------ --------- 94036686 Seal, Hub inner Oil 2 94036690 Seal, Hub Outer Oil 2 94057671 Bearing, Hub inner 2 94057672 Bearing, Hub Outer 2
WARRANTY INFORMATION
Dealers should submit a warranty claim on each vehicle completed under this campaign.
LABOR *TIME TROUBLE OPERATION DESCRIPTION ALLOWANCE CODE NUMBER ----------- ------------- --------- ------- V6630 Replace both 4.4 Hrs. 96 left and right inner/outer bearings and inner/outer oil seals
For dealer to receive Administrative Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.
CAMPAIGN IDENTIFICATION LABEL
Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label" Each label provides a space to include the campaign number and five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or ball point pen.
Each "Campaign Identification Label" is to be located on the cab inner panel in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.
Apply "Campaign Identification Label" only on a clean, dry surface.
ADMINISTRATIVE PROCEDURE
Procedures covering this campaign are outlined in Section V of your dealership's "GM Truck Claims Processing Manual" #P8919.
Dear General Motors Truck Owner:
This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act.
General Motors has learned that certain 1991 W7 GMC Forward - Chevrolet Tiltmaster vehicles have defective rear axle wheel bearings. These wheel bearings have improperly machined inner races which can cause excessive friction under some operating loads, resulting in seizure of either the inner or outer bearing at very low mileage. This bearing seizure can cause noise, possible rear wheel lockup, or possible rear wheel separation. If lockup or separation occurs while the vehicle is in motion, a vehicle crash could occur without prior warning.
To correct this condition, dealers will replace the inner and outer bearings and oil seals on both sides of the rear axle. This service will be completed for you at no charge.
Instructions for performing this service have been sent to your GM dealer. Please contact your dealer to arrange a service date. The labor time necessary to perform this correction is approximately 5 hours. Ask your dealer how much additional time will be needed to process your vehicle.
Your GM dealer is best equipped to provide service to ensure your vehicle is corrected as promptly as possible. However, if you take your vehicle to your dealer on the agreed service date and they do not service this condition on that date or within five days, we recommend you contact your nearest GMC Truck Zone Office by telephone. The Zone Office will assist you and your dealer in getting your vehicle corrected. The telephone numbers of the Zone Offices are listed in your Warranty and Owner Assistance Information Manual.
After contacting your dealer and the Zone Office, if you are still not satisfied that we have done our best to remedy this condition without charge within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590, or call 800-424-9393 (Washington, D.C. residents use 366-0123).
The enclosed postage paid owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please furnish us complete name and address of the person you sold or traded your vehicle to and return the card to us.
We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continued satisfaction with our product.
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.
