Fulltext TSBs

Technical Service Bulletins

TSB
98-15-8
  • STEERING – SHIMMY – DIAGNOSTIC PROCEDURE – 4X2 AND 4X4 VEHICLES
Publication Date: AUGUST 3, 1998

LIGHT TRUCK:
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.


Figure 1 – Article 98-15-8




Figure 2 – Article 98-15-8




Figure 3 – Article 98-15-8




Figure 4 – Article 98-15-8

(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.


Figure 5 – Article 98-15-8

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.


Figure 6 – Article 98-15-8

INSPECT THE FRAME IN THE FOLLOWING AREAS:

Frame rail near the steering gear top and bottom flanges

Frame rail at the steering bolt heads

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.

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 should increase when turning the tire straight ahead. If no increase in effort is noted, perform the procedure as outlined in Section 11-02B of the Service/Workshop Manual to check and adjust the meshload.

BALL JOINTS OR WORN KING PINS

For proper diagnosis and replacement of king pins and ball joints, refer to the Service/Workshop Manual, Section 04-00.

WHEEL BEARING END PLAY

For proper diagnosis, adjustment, or replacement of the wheel bearing, refer to the Service/Workshop Manual, Sections 04-00 and 04-01A.

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

Compare tire size and wheel size with sizes and pressures on the certification label. Inflate to the specified pressure. Assure correct balance of the front wheels.

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

Steering damper installation sketches are in the Light Truck Service/Workshop Manual for F-250 HD 4X4. Using the F-250 HD 4X4 template, install the mounting brackets and damper as shown in Figures 7 and 8 as well as the Figures provided in the kit.


Figure 7 – Article 98-15-8




Figure 8 – Article 98-15-8

Steering damper installation sketches are shown in the appropriate Service/Workshop Manual for F-250 HD/350 4X2, F-350 4X4 and Super Duty vehicles.

Install the mounting brackets and the damper as shown in Figures 9, 10, 11, and 12.


Figure 9 – Article 98-15-8




Figure 10 – Article 98-15-8




Figure 11 – Article 98-15-8




Figure 12 – Article 98-15-8

  1. When locating the mounting bracket on the steering linkage, turn the wheels to either a full LH or RH lock position.
  2. Locate the mounting bracket so the damper has an approximate 12.7mm (0.5″) of additional travel before the damper’s maximum amount of travel, as shown in Figure 9.
  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.
  4. Tighten all bolts as shown in Figures 8, 10, 11 and 12, depending on which vehicle you are repairing.

ROAD TEST

After repairs or adjustments have been made, road test the vehicle to be sure shimmy is not present.

PART NUMBERPART NAME
E7TZ-3E651-CSteering Damper Kit (F-350 4X4 SRW And DRW)
E8TZ-3E651-BSteering Damper Kit (F-Super Duty Chassis Cab F-47)
F7TZ-3E650-CASteering Damper Kit (F-250 HD 4X4)
F7TZ-3E651-BASteering Damper Kit (F-250 HD/350 4X2 SRW And DRW)
E8TZ-3B008-BSteering Linkage (F-350 4X4 SRW And DRW)
F6AZ-3575-AASteering Gear Sector Shaft Repair Kit

OTHER APPLICABLE ARTICLES:

NONE

SUPERSEDES:

97-21-11

WARRANTY STATUS:

Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage For 1992-97 Model Years, Basic Warranty Coverage For 1988-91 Model Years

OPERATIONDESCRIPTIONTIME
981508AInspect Steering Linkage, Frame Ball Joints Or King Pins (Includes Road Test, Check Torque Specifications, Inspect Steering Linkage Joints And Gear Box Mounting Surface)1.2 Hrs.
981508BReplace Tie Rod, Tie Rod End And/Or Drag Link Assembly – One (1) Or Two (2)0.5 Hr.
981508CReplace Tie Rod, Tie Rod End And/Or Drag Link Assembly – Three (3) Or More0.6 Hr.
981508DInspect Wheel Bearing End Play And Presence Of Steering Gear Meshload0.2 Hr.
981508ETAdjust Both Front Wheel Bearings0.9 Hr.
981508FAdjust Steering Gear Only – In Chassis0.6 Hr.
981508GReplace Steering Gear Sector Shaft1.7 Hrs.
981508HCheck Front Tire Balance0.4 Hr.
981508ICheck Tire Size And Pressure, Measure Alignment Settings1.1 Hr.
981508JReset Alignment To Specifications0.6 Hr.
981508KInstall Steering Damper Kit (Includes Road Test For Verification)1.2 Hrs.

DEALER CODING

BASIC PART NO.CONDITION CODE
3E65133

OASIS CODES:

303000, 304000, 306000, 703000, 703200, 703300


Copyright 1998 Ford Motor Company