CAMPAIGN: TIE ROD FRACTURE 1991 C3500 HD CHASSIS CAB

SUBJECT: TIE ROD FRACTURE

MODELS: 1991 C 3500 HD CHASSIS CAB

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 determined that a defect which relates to motor vehicle safety exists in certain 1991 C3500 HD Chassis Cab Trucks with a GVW of 15,000 lb. These vehicles may exhibit a fatigue fracture of the tie rod through the damper stud mounting hole. It a fracture occurs, the vehicle would pull to the left during braking or when driving on a rough road and could result in a vehicle crash without prior warning.

To prevent this condition from occurring, dealers are to replace the existing tie rod assembly, damper, and damper bracket with newly designed parts. The existing drag link will be reused.

VEHICLES INVOLVED

Involved are certain 1991 C3500 HD chassis cab vehicles with a 15,000 lb. GVW built within the following VIN breakpoints:

Model Plant From Through ----- ----- ---- ------- C3500 HD Janesville SOP 1991 EOP 1991

Vehicle Identification Number Computer Listings are furnished to all involved dealers with the campaign bulletin.

DEALER CAMPAIGN RESPONSIBILITY

All unsold new vehicles in dealers' possession and subject to this campaign MUST be held and inspected/repaired per the service procedure of this campaign bulletin BEFORE owners take possession of these vehicles.

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.

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.

In summary, whenever a vehicle subject to this campaign enters your vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle.

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

o Chock the rear wheels, lift and support the front axle with jack stands.

1. Remove the front tire and wheel assemblies (retain lug nuts).

2. Remove and discard the bolt (Figure 1, "2"), two (2) nuts (Figure 1, "3" and "4"), coffer pin (Figure 1, "5"), and the steering linkage absorber (Figure 1, "1") which is attached to the front axle mounting bracket.

3. On driver's side only: remove and retain the U-bolt (Figure 1, "A"), nuts (Figure 1, "C"), and washers (Figure 1, "B") which secure the front stabilizer bar to the front axle mounting bracket.

4. Remove and discard the remaining nut (Figure 1, "10"), washer (Figure 1, "9"), and bolts (Figure 1, "7" and "8") which mount the front axle mounting bracket (Figure 1, "11") to the front axle. Then remove and discard the front axle mounting bracket.

5. Enlarge the forward hole in the axle beam, used for the front axle mounting bracket, using the 15mm drill (Special Tool J39605).

Note: This is the through hole on the front axle which is closest to the front bumper and is the hole through which bolt "3" in Figure 2 passes. Care should be taken to keep the new hole aligned with the old hole. THE HOLE MUST BE DRILLED FROM THE BOTTOM OF THE AXLE UP USING A SPECIAL DRILL BIT (Special Tool J39605). THE DRILL MUST BE ORDERED FROM KENT MOORE TOOLS. THIS DRILL BIT IS REQUIRED DUE TO AN INTERFERENCE WITH THE BOTTOM FLANGE OF THE FRONT AXLE When used properly, each drill bit should drill 3-5 axles.

6. Install a replacement front axle mounting bracket (P/N 15696702) (Figure 2, "1") using a new M10 bolt (P/N 15659623) (Figure 2, "2"), torque to 60-75 N.m. (44-55 lbs. ft.) and a new M14 bolt (P/N 11509775) (Figure 2, "3"), M14 washer (P/N 15531206) (Figure 2, "4"), and M14 lock nut (P/N 11500748) (Figure 2, "5"), torque to 120-130 N.m. (89-96 lbs. ft.). The M14 bolt (P/N 11509775) must be installed in the direction shown in Figure 2 view B.

7. Reinstall the retained U-bolt, nuts, and washers and torque to 24-32 N.m. (18-24 lbs. ft.)

8. Remove and discard the cotter pin (Figure 1, "15") and the castle nut (Figure 1, "14") which retain the drag link to the tie rod assembly.

9. Using a tie rod puller (J-6627A) or universal steering linkage puller (J-29107) disconnect the drag link from the tie rod assembly. Note: The joint seal will be damaged if the proper tool is not used.

10. Remove and discard the cotter pins (Figure 1, "13") and castle nuts (Figure 1, "12") retaining the tie rod assembly to the right and left spindles.

11. Using a tie rod puller (J-6627A) or universal linkage puller (J-29107) disconnect the tie rod assembly from the right and left spindles. Discard the tie rod assembly (Figure 1, "6").

12. Install new tie rod assembly (P/N 26035161) (Figure 2, "6") to right and left spindles using two of the new 5/8-18 castle nuts (Figure 2 "7") and torque to 75-100 N.m. (55-74 lbs. ft.) Retain the castle nuts to the right and left spindle locations using two of the new 1/8" x 1 1/2" cotter pins (Figure 2, "18").

13. Connect the drag link to the new tie rod assembly (Figure 2, "6") using the remaining new 5/8-18 castle nut (Figure 2, "14") and torque to 95-115 N.m. (70-85 lbs. ft.). Retain the castle nut with the remaining new 1/8" x 1 1/2" coffer pin (Figure 2, "15").

14. Install a new steering linkage absorber (P/N 22064604) (Figure 2, "9") to new tie rod assembly (P/N 26035161) (Figure 2, "6") using a new M10 bolt (P/N 11509142), M10 lock nut (P/N 11501033), and M10 washer (P/N 15614758) (Figure 2, "10", "11", and "12"), torque to 40-50 N.m. (30-37 lbs. ft.).

Note: The bolt must be installed in the direction shown in view A.

15. Install the new steering linkage absorber to the new front axle mounting bracket using a new M10 bolt (P/N 11509142) (Figure 1, "10"), and M10 lock nut (P/N 11501033) (Figure 1, "11"), and torque to 40-50 N.m. (30-37 lbs. ft.).

16. Retrieve the retained lug nuts and reattach the front tire and wheel assemblies. Torque the lug nuts to 240 N.m. (177 lbs. ft.).

17. Perform a complete toe-in adjustment. The steering wheel must be locked and centered. The toe-in should be set to the following specifications:

Service Checking Service Setting ---------------- --------------- Sum 0.06 +/- 0.06 in. 0.06 +/- 0.06 in. Toe-In 1.52 +/- 1.52 mm. 1.52 +/- 1.52 mm. 0.12 +/- 0.12 degrees 0.12 +/- 0.12 degrees

Note: This is a new tie rod system.

18. Align the front right wheel (Passenger Side) by using the drag link adjuster tube assembly and the following procedure:

a. Position the drag link adjuster clamps on the adjuster tube so the edge of the clamp ears do not tall on the adjuster tube slot (Figure 3, view A).

b. Adjuster clamps must be located BETWEEN (not ON) the stamped adjuster tube dimples.

c. The ears of the drag adjuster tube clamps must be rotationally positioned as specified on Figure 3, view A.

d. Tighten the drag link adjuster clamp nuts to 68 N.m. (50 lbs. ft.)

e. The drag link assembly must be capable of rocking on the socket pivots through a minimum of eight (8) degrees total after the clamps are tightened.

Note: If tools are used to rotate the adjuster tube, special attention must be given to prevent damage to the corrosion protection coating.

19. Align the front left wheel (Drivers Side) by using the tie rod adjuster tube assembly and the following procedure:

a. Position the tie rod adjuster clamps on the adjuster tube so that the edge of the clamp ears do not fall in the adjuster tube slot (Figure 3, view A).

b. Adjuster tube clamps must be located BETWEEN (not ON) the stamped adjuster tube dimples.

c. The ears of the tie rod adjuster tube clamps must be rotationally positioned as specified in Figure 3, view B.

d. Tighten the tie rod adjuster clamp nuts to 68 N.m. (50 lbs. ft.).

Note: If tools are used to rotate the adjuster tube, special attention must be given to prevent damage to the corrosion protection coating.

20. Remove the axle supports and the lower hoist.

21. Install a "Campaign Identification Label."

SERVICE PARTS INFORMATION

Parts are to be obtained from General Motors Service Parts Operation (GMSPO). To ensure that these parts will be obtained as soon as possible, they should be ordered from GMSPO on a C.I.O. order with no special instruction code but order under an advise code (2).

Part Description Qty Number ----------- --- ------ 15696702 Front Axle Mounting Bracket 1 15659623 Bolt - M10 - 1.5 x 30.0 1 11509775 Bolt - M14 - 2.0 x 50.0 1 15531206 Washer - M14 1 11500748 Nut - M14 - 2.0 Lock 1 26035161 Tie Rod Assembly (Includes 1 3 Castle Nuts - 5/8-18 and 3 Cotter Pins - 1/8" x 1 1/2") 22064604 Steering Linkage Absorber 1 11509142 Bolt - M10 - 1.5 x 65.0 2 11501033 Nut - M10 - 1.5 Lock 2 15614758 Washer - M10 Hardened 1

To be ordered from Kent Moore Tools (1-800-345-2233): J39605 Special 15 MM Dia. Drill Bit 1

Note: EACH DRILL BIT SHOULD DRILL 3-5 AXLES.

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

Labor *Time Trouble Operation Description Allowance Code Number ----------- --------- ------- --------- V7390 Tie Rod - Replace 1.6 hrs. 96

*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 radiator core support 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" #P9119.

Dear GMC 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 determined that a defect which relates to motor vehicle safety exists in certain 1991 C3500 HD Chassis Cab Trucks with a GVW of 15,000 lb. These vehicles may exhibit a fatigue fracture of the tie rod through the damper stud mounting hole. If a fracture occurs, the vehicle would pull to the left during braking or when driving on a rough road and could result in a vehicle crash without prior warning.

To prevent this condition from occurring, dealers are to replace the existing tie rod assembly, damper, and damper bracket with newly designed parts. The existing drag link will be reused. This service will be completed for you at no charge.

Instructions for performing this service have been sent to your GMC dealer. Please contact your dealer to arrange a service date. The labor time necessary to perform this correction will vary from one hour and thirty minutes to two hours. Please ask your dealer how much additional time will be needed to process your vehicle.

Your GMC 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 retum 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.