STEERING SHIMMY DIAGNOSTIC PROCEDURE Article No. 4X2 AND 4X4 VEHICLES 98-15-8 FORD: 1988-1997 F SUPER DUTY, F-250 HD, F-350 This TSB article is being republished in its entirety to include the latest level parts and to include the F-250 HD 4X4. The F-250 and F-350 listed include 4X4 and 4X2. ISSUE Front end shimmy may occur at various driving speeds and is usually induced when hitting bumps such as large potholes or rough railroad crossings. Shimmy is not always verified during the road test. ACTION Check all the systems that can cause shimmy. After a general review of the front suspension and steering systems, make the necessary adjustments as noted in the following diagnostic procedure. The review should include bolt and nut torques to ensure they are to specified torques. When encountering excessively worn tires, shackle bushings and out-of-balance wheel or tire assemblies, refer to the appropriate Service/Workshop Manual, Section 04-00. Shimmy, as observed by the driver, is defined as large amplitude, rotational oscillations of the steering wheel resulting from large, side-to-side (lateral) tire/wheel movements. Shimmy should not be confused with nibble, a condition resulting from tire interaction with various road surfaces and observed by the driver as small amplitude, rotational oscillations of the steering wheel. To diagnose nibble and other vibrations which are sometimes confused with shimmy, such as steering column shake or wheel/tire imbalance, consult the Noise/Vibration/Harshness (NVH) diagnostic, Brake NVH and Tire NVH sections in the appropriate Service/Workshop Manuals. The following items will contribute to the shimmy condition and should be inspected and repaired as required to assure the total repair effectiveness. After all components have been reviewed and repaired, install the appropriate Steering Damper Kit. STEERING LINKAGE With the vehicle weight on the front wheels, observe the steering linkage joints while someone else turns the vehicle steering wheel from side-to-side. (RBS) RUBBER BALL SOCKET LINKAGE Observe if the ball stud makes contact with RBS linkage. Observe if the ball stud makes contact with the window opening in the socket bowl, refer to Figure 1. Then remove the linkage and determine if the rubber is torn. If contact is made with the window opening or the rubber is torn, replace with a greaseable, steel socket. Refer to Figures 2, 3 or Figure 4 for applicable replacement parts. (GREASEABLE) STEEL LINKAGE For steel (greaseable) joints, measure and observe lateral (side-to-side) lash in the joint. If the lash exceeds 1.5mm (0.060 ), the joint should be replaced. Refer to Figure 5. With the linkage removed, check the vertical end play. If the end play is greater than 2.3mm (0.090 ), replace the joint, Figure 5. Also, determine if the steel joint spins freely. If the joint spins freely by hand, the joint should be replaced. Refer to Figures 2, 3 or Figure 4 for applicable replacement parts. FRAME Inspect the mounting surface of the gear and the mounting area of the frame, shown in Figure 6, for signs of motion, for loose rivets, and for cracks. Removal of the gear from the frame may be required. All damages must be repaired. Refer to the Service/Workshop Manual, Section 02-01, for service procedures. INSPECT THE FRAME IN THE FOLLOWING AREAS: Frame rail near the steering gear top and bottom flanges Frame rail at the steering bolt heads PROOF 14-MAR-00 96-0947 96-0947 PAGE 1
Article No. 98-15-8 Cont d. Frame rail at or near the leaf spring mounting brackets Front crossmember where the track bar mounting bracket mounts STEERING GEAR If shimmy has been experienced, replace the steering gear sector shaft with Repair Kit (F6AZ-3575-AA) as outlined in the appropriate Service/Workshop Manual. STEERING DAMPER A Steering Damper Kit should be installed when shimmy is experienced. Install the following applicable Service Kit: F-250 HD/350 4X2 SRW and DRW vehicles - F7TZ-3E651-BA F-250 HD 4X4 (see template when installing kit) - F7TZ-3E650-CA F-350 4X4 SRW and DRW vehicles - E7TZ-3E651-C F-Super Duty Chassis Cab (F-47) - E8TZ-3E651-B Check the steering gear for presence of meshload. With the front wheels off the ground, hold the tire and turn the tire side-to-side slowly. The effort Steering damper installation sketches are in the should increase when turning the tire straight Light Truck Service/Workshop Manual for F-250 HD ahead. If no increase in effort is noted, perform the 4X4. Using the F-250 HD 4X4 template, install the procedure as outlined in Section 11-02B of the mounting brackets and damper as shown in Figures Service/Workshop Manual to check and adjust the 7 and 8 as well as the Figures provided in the kit. meshload. Steering damper installation sketches are shown in the appropriate Service/Workshop Manual for F-250 BALL JOINTS OR WORN KING PINS HD/350 4X2, F-350 4X4 and Super Duty vehicles. For proper diagnosis and replacement of king pins Install the mounting brackets and the damper as and ball joints, refer to the Service/Workshop shown in Figures 9, 10, 11, and 12. Manual, Section 04-00. 1. When locating the mounting bracket on the WHEEL BEARING END PLAY steering linkage, turn the wheels to either a full LH or RH lock position. For proper diagnosis, adjustment, or replacement of the wheel bearing, refer to the Service/Workshop 2. Locate the mounting bracket so the damper has Manual, Sections 04-00 and 04-01A. an approximate 12.7mm (0.5 ) of additional travel before the damper s maximum amount of travel, as shown in Figure 9. ALIGNMENT All alignment adjustments should be measured and set to the recommended specifications as stated in the Service/Workshop Manual, Section 04-00. WHEEL/TIRE SIZE AND BALANCE 3. Turn the wheels to the opposite lock position and check the damper travel to be sure the maximum amount of travel has not been reached. The damper should not prevent the wheels from reaching their lock-to-lock turning positions. Compare tire size and wheel size with sizes and 4. Tighten all bolts as shown in Figures 8, 10, 11 pressures on the certification label. Inflate to the and 12, depending on which vehicle you are specified pressure. Assure correct balance of the repairing. front wheels. ROAD TEST After repairs or adjustments have been made, road test the vehicle to be sure shimmy is not present. PAGE 2 96-0947 96-0947 PROOF 14-MAR-00
Article No. 98-15-8 Cont d. PART NUMBER PART NAME 981508C Replace Tie Rod, Tie Rod 0.6 Hr. E7TZ-3E651-C Steering Damper Kit (F-350 4X4 SRW End And/Or Drag Link And DRW) Assembly - Three (3) Or E8TZ-3E651-B Steering Damper Kit (F-Super Duty More Chassis Cab F-47) 981508D Inspect Wheel Bearing End 0.2 Hr. F7TZ-3E650-CA Steering Damper Kit (F-250 HD 4X4) F7TZ-3E651-BA Steering Damper Kit (F-250 HD/350 Play And Presence Of 4X2 SRW And DRW) Steering Gear Meshload E8TZ-3B008-B Steering Linkage (F-350 4X4 SRW 981508ET Adjust Both Front Wheel 0.9 Hr. And DRW) Bearings F6AZ-3575-AA Steering Gear Sector Shaft Repair Kit 981508F Adjust Steering Gear Only 0.6 Hr. - In Chassis OTHER APPLICABLE ARTICLES: 96-20-13, 981508G Replace Steering Gear 1.7 Hrs. NONE Sector Shaft SUPERSEDES: 97-21-11 981508H Check Front Tire Balance 0.4 Hr. WARRANTY STATUS: Eligible Under The 981508I Check Tire Size And 1.1 Hr. Provisions Of Bumper To Pressure, Measure Bumper Warranty Coverage Alignment Settings For 1992-97 Model Years, 981508J Reset Alignment To 0.6 Hr. Basic Warranty Coverage Specifications For 1988-91 Model Years 981508K Install Steering Damper Kit 1.2 Hrs. OPERATION DESCRIPTION TIME (Includes Road Test For 981508A Inspect Steering Linkage, 1.2 Hrs. Verification) Frame Ball Joints Or King DEALER CODING Pins (Includes Road Test, CONDITION Check Torque BASIC PART NO. CODE Specifications, Inspect 3E651 33 Steering Linkage Joints OASIS CODES: 303000, 304000, 306000, 703000, And Gear Box Mounting 703200, 703300 Surface) 981508B Replace Tie Rod, Tie Rod 0.5 Hr. End And/Or Drag Link Assembly - One (1) Or Two (2) PROOF 14-MAR-00 96-0947 96-0947 PAGE 3
Article No. 98-15-8 Cont d. Figure 1 - Article 98-15-8 Figure 2 - Article 98-15-8 PAGE 4 96-0947 96-0947 PROOF 14-MAR-00
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