Fulltext TSBs

Technical Service Bulletins

TSB
98-5A-46
  • BRAKES – PULL OR DRIFT TO LEFT – NEGATIVE CASTER SPLIT – RADIUS ARM REPLACEMENT – 4X4 MODELS
  • STEERING – PULL OR DRIFT TO LEFT – NEGATIVE CASTER SPLIT – RADIUS ARM REPLACEMENT – 4X4 MODELS
Publication Date: MARCH 18, 1998

LIGHT TRUCK:
1988-1996 BRONCO, F-150

ISSUE:

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.

ACTION:

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.

SERVICE PROCEDURE

  1. Determine the amount of caster split the vehicle has by measuring the caster of both front wheels on an alignment machine.
  2. 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.
  3. 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
  4. 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.
  5. 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 NumberCaster BiasPaint Code Color
    F6TZ-3A360-AA0.25 DegreeOrange
    F6TZ-3A360-BA0.50 DegreeGreen
    F6TZ-3A360-CA0.75 DegreePurple
    F6TZ-3A360-DA1.00 DegreePink

  6. 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.
  7. Recheck caster and determine that caster split is within specification.



PART NUMBERPART NAME
F6TZ-3A360-AARadius Arm – RH (0.25 Degree Bias)
F6TZ-3A360-BARadius Arm – RH (0.50 Degree Bias)
F6TZ-3A360-CARadius Arm – RH (0.75 Degree Bias)
F6TZ-3A360-DARadius Arm – RH (1.00 Degree Bias)

OTHER APPLICABLE ARTICLES:

94-20-13,98-5A-39

SUPERSEDES:

95-25-9

WARRANTY STATUS:

Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage For 1993-96 Model Years, Basic Warranty Coverage For All Other Model Years

OPERATIONDESCRIPTIONTIME
985A46AReplace Right Radius Arm And Check Alignment1.5 Hrs.

DEALER CODING

BASIC PART NO.CONDITION CODE
3405W6

OASIS CODES:

301000, 303000


Copyright 1998 Ford Motor Company