Steering - Returnability Diagnostics
Article No. 85-16-16STEERING - RETURNABILITY - DIAGNOSTIC PROCEDURE
LIGHT TRUCK 1980-85 F100/150 4x2/4x4, BRONCO
Vehicles that exhibit "sticky" steering may have a tendency not to return to the desired straight ahead direction after a steering wheel input of 20~. A vehicle with this condition may also require centering of the steering wheel by the driver after a sharp turn, rather than return by itself due to road forces at the tire.
This condition may be corrected by proper diagnosis and servicing of the steering system as outlined in the Roadability Section (19-01) of the 1985 Light Truck Shop Manual and this supplemental information.
Sticky steering may be the result of:
^ Excessive spindle turning efforts
^ High steering linkage ball stud turning torques (not applicable to vehicles equipped with rubber ball stud linkage)
^ High steering gear meshloads
Spindle Rotating Torque Twin I-Beam Axle with Ball Joints
To check spindle turning efforts, disconnect the steering linkage at the steering knuckle. For all 4x2's, rotate the spindle back and forth quickly ten (10) times. Use a dial indicator torque wrench on the lower ball joint nut. Rotate the spindle from stop to stop slowly (1 RPM) and measure the maximum torque to rotate. Specification is 4-20 N-m (3-15 ft.lbs.) at room temperature.
To check turning efforts on all 4x4's, push the spindle at the end of the steering arm with a push-pull gauge at 1 RPM. Multiply the reading by 0.5 for F150 4x4 and Bronco. Specification is 4-20 N-m (3-15 ft.lbs.) at room temperature.
If the spindle rotational torque is within the specified range, check the steering gear meshload and steering linkage ball stud turning torques (not applicable to vehicles equipped with rubber ball stud linkage). Refer to the Light Truck Shop Manual for proper diagnosis and repair.
If the spindle rotational torque is above the specified range for ball joint spindle/knuckle systems, perform the following:
^ Rotate the spindle back and forth from stop to stop and check for clearance between the spindle and the axle. Interference between the two surfaces will cause the spindle to bind resulting in high turning efforts.
^ If no interference exists, perform the following.
F150 4x4 and Bronco Vehicles
1. Remove the upper ball stud cotter pin and fastener.
2. Use Pitman arm puller T64P-3590-F or equivalent with spacer against the end of the stud to break the camber adjuster loose. Leave the nut on the end of the stud if necessary to protect the thread.
3. Measure and record the upper ball joint turning torque as follows:
Install the castellated nut upside down on the stud and insert the cotter pin. Rotate the stud back and forth quickly ten (10) times.
4. Measure and record the upper ball stud turning torque at 10 RPM using a dial indicator torque wrench. If the torque exceeds 6.7 N-m (60 in.lbs.), replace the ball joint as described in the 1985 Light Truck Shop Manual, Section 14-21, Front Suspension Twin I-Beam.
5. Measure and record the lower ball joint turning torque as follows:
Orientate the front axle shaft U-joint cross between the ball joints, such that it is parallel to ball joint studs.
Rotate the spindle back and forth quickly ten (10) times.
Push the spindle at the end of the steering arm with push-pull gauge at 1 RPM. Multiply the reading by 0.5 for F150 4x4 and Bronco.
6. If the ball joint torque exceeds 6.7 N-m (60 in.lbs.), remove the ball joint as described in the 1985 Light Truck Shop Manual, Section 14-21, Front Suspension Twin I-Beam. Then re-evaluate the torque at 10 RPM using a dial indicator torque wrench. Replace if the turning torque exceeds 4.0 N-m (35 in.lbs.).If the torque is within specification, inspect the axle shaft U-joint for binding.
7. If replacement ball joints are required, evaluate the torque of each before installation.
NOTE: If the ball joint torques are within specification, high spindle turning efforts are the result of torquing the fasteners out of sequence which preloads the ball joint improperly.
8. Loosen the lower ball joint nut to the end of the stud and strike the spindle near the lower ball joint to break the spindle loose from the stud.
NOTE: The following torque sequence must be followed EXACTLY when securing the spindle.
9. Make sure that the ball joint rubber grease boot is seated at the base of the stud against the socket.
10. Wipe any grease from the studs.
11. Install the steering knuckle and tighten the lower nut to 47 N-m (35 ft.lbs.).
12. For all vehicles, install the nut and tighten to 136 N-m (100 ft.lbs.). Advance the nut to the next castellation and install a new cotter pin.
13. Finish tightening the lower nut to 129-149 N-m (95-110 ft.lbs.).
14. The camber adjuster will seat itself into the spindle at a predetermined position during the tightening sequence. DO NOT attempt to adjust this position.
15. Recheck the spindle rotational torque using the push-pull gauge as described above to ensure it does not exceed 20 N-m (15 ft.lbs.).
F150 4x2 Vehicles
1. Remove the nut from the upper ball joint stud.
2. Loosen but do not remove the lower ball joint stud nut.
3. Strike the inside of the spindle near the upper and lower ball joints to break the spindle loose from the ball joint studs.
4. Remove caliper assembly from spindle and secure it out of the way with wire.
5. Remove the lower ball joint nut and remove the spindle.
6. Measure each ball stud turning torque as follows:
Install the nut and run it down to the bottom of the threads against the taper. Before measuring the turning torque, rotate the stud in its socket ten (10) times. Evaluate the torque, using a dial indicator torque wrench, by rotating the stud at approximately 10 RPM. If the ball stud turning torque exceeds 6.7 N-m (60 in.lbs.), replace the ball joint as described in the 1985 Light Truck Shop Manual, Section 14-21, Front Suspension Twin I-Beam.
7. Check the ball joint turning torque of the replacement ball joint as described above before installaation.
NOTE: If either ball joint exceeds stud turning torque specification, high spindle turning effort is the result of tightening the attaching nuts out of sequence which preloads ball joints improperly.
Install spindle EXACTLY as described below.
8. Place the camber adjuster in the spindle.
NOTE: Wipe away any grease from ball joint studs and ensure that ball joint rubber grease boot is fully seated at base of stud against socket.
9. Install the spindle on the axle.
10. Apply Loctite 242 or equivalent to the upper and lower ball stud threads.
11. Tighten the lower ball stud nut to 47 N-m (35 ft.lbs.).
12. Tighten the upper ball stud nut to 115-150 N-m (85-110 ft.lbs.).
13. Finish tightening the lower nut to 130 N-m (140 ft.lbs.).
CAUTION: The camber adjuster will seat itself into spindle at a predetermined position during tightening sequence. DO NOT attempt to adjust this position.
14. Recheck the spindle rotational torque to ensure the maximum 20 N-m (15 ft.lbs.) specification is not exceeded.
15. Advance the castellated nut to install a new cotter pin.
16. Attach caliper to spindle.
F100/150 4x2 Twin I-Beam Forged Axle with King Pins
Check spindle turning torques with the linkage disconnected as follows:
NOTE: Measure spindle turning force at spindle arm to linkage stud hole.
F100/150 4x2 with forged axle - Apply force to end of spindle arm and rotate back and forth quickly ten (10) times. If over ten
(10) lbs. of force is required to rotate the spindle with a push-pull gauge, or if it grabs or sticks during movement, remove the king pin and clean/remove burrs on spindle bushings and pin. Pre-lube spindle bushings and reassemble as shown in the 1985 Shop Manual, Section 14-21, Front Suspension Twin I-Beam. Pressure lubricate at both grease fittings and recheck rotational force.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"