Steering Wheel - Nibble/Shimmy/Vibration
88ford1
VIBRATION - STEERING WHEEL NIBBLE AND SHIMMY
Article No. 88-1-11
MERKUR: 1985-88 XR4Ti
ISSUE: Steering wheel nibble and shimmy may be caused by incorrect tire pressure, incorrect tire balance or wheel and tire assembly radial and lateral runout. On 1985 vehicles built before 06/28/85 equipped with a Cam (TRW) steering gear, this condition may occur while driving on a smooth road surface at either a steady speed of 30 to 45 mph (48-72 km/h) or coast-down from 45 to 35 mph (72-56 km/h). This can be caused by the steering gear preload spring.
ACTION: To correct this, install a new steering gear preload spring on 1985 vehicles and perform the following procedure for steering wheel nibble and shimmy diagnosis on 1985-88 vehicles.
1985 VEHICLES ONLY
1. Raise the vehicle on a hoist.
2. Remove two (2) attaching screws and clamps holding the primary cooler lines to the steering gear. Rotate cooler lines to access steering gear yoke plug.
3. Remove yoke plug using the yoke plug hex adapter tool (T85M-3504-C).
NOTE: Drill a 1/2" hole in the center of the face of the adapter tool so tool will fit over the preload spring button that sticks out from the yoke plug.
4. Remove steering gear preload spring and throw away.
5. Remove grease and sealant from threads of yoke plug and yoke bore.
6. Install a new design preload spring (E5RY-3Z591-A).
7. Apply Ford Threadlocker and Sealer (E0AZ-19554-AA) to the yoke plug.
8. Reinstall yoke plug into yoke bore using yoke plug adapter tool (T85M-3504-C). Torque yoke plug to 15-17 in.lbs. (1.7-1.9 N-m).
9. Stake yoke plug to yoke bore in three (3) positions.
10. Install primary cooler lines to steering gear assembly.
11. Road test vehicle.
12. Proceed to Step 1 of the next diagnostic procedure for 1985-88 vehicles, if steering nibble is still present.
ALL MODEL YEARS -
DIAGNOSTIC PROCEDURE
1. Check tire inflation pressures. All tires should be set to 28 psi.
2. Check wheel and tire balance using an on-car balancer.
3. Check wheel and tire assemblies for radial and lateral runout using radial runout gauge 007-00014. These must be measured on the inside flange of the machined surfaces of the wheel.
SPECIFICATION - MAXIMUM
Wheel Radial = 0.4 mm (0.0157 in.)
Wheel Lateral = 0.5 mm (0.0197 in.)
Wheel/Tire Radial = 1.6 mm (0.063 in.)
Wheel/Tire Lateral = 1.8 mm (0.071 in.)
FIGURE 5:
4. Check for brake rotor runout as follows:
a. Using a suitable dial indicator D78P-4201-B with holding fixture D79P-4201-F, measure rotor runout, Figure 5. Measure runout about 10 mm (3/8 in.) in from outside diameter. Rotate hub and rotor assembly. Record indicator reading. If runout is greater than 0.08 mm (0.003 in.) total indicator reading, the rotor should be repositioned on hub at 90 degree increments until the lowest reading is obtained. If an acceptable runout can be obtained, reinstall and road test to see if steering wheel nibble and shimmy is corrected.
FIGURE 4:
5. If less than 0.08 mm (0.003 in.) rotor runout cannot be obtained by repositioning the rotor, check for spindle hub face runout as follows:
a. Remove rotor, clean hub face and check hub face runout just inside wheel studs, Figure 4. This reading must be within 0.06 mm (0.002 in.) total indicator reading.
b. If hub is outside specification, a new hub must be installed. If hub runout is within specification, replace rotor.
PART NUMBER PART NAME CLASS
E5RY-3Z591-A Preload Spring BG
E0AZ-19554-AA Ford Threadlocker and B
Sealer
OTHER APPLICABLE ARTICLES: Supersedes 86-9-8
WARRANTY STATUS: Eligible Under Major Component Coverage
OPERATION: 880111A - Install preload spring on 1985 units and road test
TIME: 0.7 Hr.
OPERATION: 880111B - Steps 1-4 of the diagnostic procedure
TIME: 0.9 Hr.
OPERATION: 880111C - Step 5 of the diagnostic procedure (one hub replaced)
TIME: 0.4 Hr.
OPERATION: 880111D - Step 5 of the diagnostic procedure (both hubs replaced)
TIME: 0.8 Hr.
DLR. CODING: Basic Part No. Code:
3504 - Preload spring 67
1104 - Front hub 67