Technical Service Bulletins
|Publication Date: MARCH 18, 1998|
|1988-1996 BRONCO, F-150|
A steady state drift to the left or pull to the left while braking may occur on some vehicles. This may be caused by the negative caster split (caster variation with less caster on the left side versus the right side) being out of specification.
Determine vehicle alignment readings. If negative caster split is out of specification (0 ±0.4 degrees), select the appropriate right side radius arm to bring caster split back to specification. Refer to the following Service Procedure for details.
|NOTE:||CURRENT PRODUCTION RADIUS ARMS HAVE 1.2 DEGREE (BRONCO) OR 1.5 DEGREE (F-150) CASTER BIAS BUILT INTO THE RIGHT SIDE RADIUS ARM. REPLACEMENT OF THE RADIUS ARMS WILL NOT AFFECT CAMBER.|
- Determine the amount of caster split the vehicle has by measuring the caster of both front wheels on an alignment machine.
- Subtract the left front wheel’s caster figure from the right front wheel’s caster figure to determine caster split. If this figure is positive (left side caster figure is smaller than the right side figure), then the vehicle is exhibiting negative caster split and this procedure will apply to the vehicle. Caster split of ±0.4 degrees is within specification.
- Obtain the paint color marking on the right side radius arm (white or yellow).
- Yellow paint markings represent a caster bias of 1.2 degrees
- White paint markings represent a caster bias of 1.5 degrees
- Subtract the caster split figure obtained in Step 2 from the caster bias figure obtained in Step 3. EXAMPLE: If the result from Step 2 is 0.5 degree, and you have a white striped right side arm (1.5 degrees caster bias), subtract the caster split result of 0.5 degree from the caster biased arm of 1.5 degrees. The final result is 1.0 degree.
- Select a replacement right side radius arm based on your result of Step 4 from the following chart (choose replacement arm which most closely matches your Step 4 result):
RIGHT SIDE RADIUS ARM REPLACEMENT Part Number Caster Bias Paint Code Color F6TZ-3A360-AA 0.25 Degree Orange F6TZ-3A360-BA 0.50 Degree Green F6TZ-3A360-CA 0.75 Degree Purple F6TZ-3A360-DA 1.00 Degree Pink
- Install the new right side radius arm. Refer to the appropriate Bronco/F-150 Service Manual, Section 04-01B, for service procedure on right side radius arm replacement.
- Recheck caster and determine that caster split is within specification.
|PART NUMBER||PART NAME|
|F6TZ-3A360-AA||Radius Arm – RH (0.25 Degree Bias)|
|F6TZ-3A360-BA||Radius Arm – RH (0.50 Degree Bias)|
|F6TZ-3A360-CA||Radius Arm – RH (0.75 Degree Bias)|
|F6TZ-3A360-DA||Radius Arm – RH (1.00 Degree Bias)|
OTHER APPLICABLE ARTICLES:
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage For 1993-96 Model Years, Basic Warranty Coverage For All Other Model Years
|985A46A||Replace Right Radius Arm And Check Alignment||1.5 Hrs.|
|BASIC PART NO.||CONDITION CODE|
Copyright © 1998 Ford Motor Company