Front Driveline - Vibration During Hard Acceleration
91ford28
Article No.
91-25-3
12/13/91
^ SUSPENSION - FRONT - RIDE HEIGHT VARIATION MAY CAUSE FRONT DRIVELINE VIBRATION DURING HARD ACCELERATION (VEHICLES BUILT BEFORE 10/16/91)
^ VIBRATION - FRONT DRIVELINE - DURING HARD ACCELERATION (VEHICLES BUILT BEFORE 10/16/91)
^ DRIVELINE - FRONT - VIBRATION DURING HARD ACCELERATION (VEHICLES BUILT BEFORE 10/16/91)
LINCOLN-MERCURY: 1990-92 CONTINENTAL
ISSUE: A front driveline vibration may occur during hard acceleration. This may happen because of side-to-side ride height variations in the computer controlled suspension system.
ACTION: Check the side-to-side ride height measurements and adjust as required. Refer to the following service procedure for details.
NOTE: PRODUCTION VEHICLES BUILT 10/16/91 AND AFTER HAVE IMPROVED, NEW DESIGN, SPRING LOADED CV JOINTS AND SHOULD NOT EXHIBIT THE SHUDDER CONDITION.
SERVICE PROCEDURE
1. Drive the vehicle and confirm the concern.
2. Park the vehicle on a level surface and set tire pressure to specification of 30 PSI.
3. Perform STAR test on suspension system to verify proper operation. Refer to the 1990/92 Service Manual, Page 14-40-9 for '90/'91 and Page 04-05-148 for '92, for "Ride Height Setup and Measuring" procedure.
a. After the Super Star II (007-0041A) or equivalent displays code "12", place the suspension switch in the OFF position and remove the tester leaving the ignition in the RUN position.
b. At this point, the vehicle will be at the highest point of "Trim Measuring".
4. Measure the front bumper-to-ground height.
a. Position a 15-3/4" (400 mm) rod at the corner or the bumper reinforcement (15 3/4", 400 mm, from the centerline of the car behind the soft fascia) to the ground.
b. If there is clearance between the reinforcement and the top of the rod, proceed to Step 5.
c. If there is no clearance, proceed to Step 9.
Figure 1:
5. Fabricate a wood block 6-1/4" (159 mm) high. Slide the block under the subframe at the location just beneath the inner mounting pivot of both right and left front lower control arm, Figure 1.
NOTE: THE REASON THAT MEASUREMENTS MUST BE TAKEN UNDER BOTH LOWER ARMS IS THAT THE HEIGHT COULD VARY FROM ONE SIDE TO THE OTHER AND THAT A DIFFERENT COLORED LINK MAY BE INSTALLED TO COMPENSATE FOR THE HEIGHT DIFFERENCE. SIDE TO SIDE VARIATION MUST NOT EXCEED 1/40 (6.35 MM).
6. If clearance to the subframe exists, the vehicle front ride height must be lowered by one (1) link as outlined in the Service Manual which is equal to 1/4" (6.35 mm).
^ When removing a link, carefully separate it from the ball stud with a wide-blade screwdriver.
CAUTION: BE CAREFUL NOT TO DAMAGE THE LINK OR BALL STUD.
^ When installing a link to the sensor, support the sensor lever from behind to avoid possible damage to the sensor.
Figure 2:
Link heights from high to low are: (Maximum High - Yellow, Green, Blue, Red, White - Maximum Low). Refer to Figure 2 for front ride height affect with respect to the nominal length.
7. Turn the suspension switch ON and redrive the vehicle checking for vibration during hard acceleration. If no vibration is found, confirm that alignment is within specification and return the vehicle to the customer.
8. If the vehicle still vibrates, return to Step 3. If there is no longer any clearance between the block and the subframe, go to Step 9.
NOTE: IF THE VEHICLE MUST BE STAR TESTED MORE THAN ONCE, A BATTERY CHARGER MUST BE CONNECTED TO MAKE SURE AN ACCURATE RIDE HEIGHT TRIM BAND IS MAINTAINED DURING EACH MEASUREMENT PROCESS.
9. If initial measuring of the vehicle ride height does not indicate the lowering procedure is to be performed, or if subsequent lowering does not resolve the vibration concern, then replace both left hand and right hand inner halfshaft CV joints. Refer to the 1990/92 Sevice Manual, Section 15-22 for '90-'91 models and Section 06-04 for '92 models, for service details. Verify front end alignment prior to returning the vehicle to the customer.
10. Direct any technical questions to the Ford
Technical Hotline: 1-800-826-4694.
11. Return all replaced halfshaft CV joints to the Warranty Parts Return Center, 1285 S. Mill St., Plymouth, MI 48170.
SPECIAL WARRANTY CODE
The unique warranty account number established to handle front driveline vibration claims is: Special Warranty Code RlT
PART NUMBER PART NAME CLASS
F20Y-3B414-A Inner Halfshaft CV Joint - RH B
F20Y-3B414-B Inner Halfshaft CV Joint - LH B
E80Y-3C111-C Height Sensor Link - LH - Front C
(Plus One Green)
E8OY-3C111-G Height Sensor Link - RH - Front B
(Plus One Green)
E8OY-3C111-B Height Sensor Link LH - Front B
(Minus One Red)
E8OY-3C111-F Height Sensor Link - RH - Front C
(Minus One Red)
E8OY-3C111-J Height Sensor Link - LH - Front B
(Nominal Blue)
E8OY-3C111-K Height Sensor Link - RH - Front B
(Nominal Blue)
E8OY-3C111-D Height Sensor Link - LH - Front C
(Plus Two Yellow)
E8OY-3C111-H Height Sensor Link - RH - Front B
(Plus Two Yellow)
E8OY-3C111-A Height Sensor Link - LH - Front B
(Minus Two White)
E8OY-3C111-E Height Sensor Link - RH - Front C
(Minus Two White)
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Basic Warranty
Coverage And Major
Component Coverage For
1990 Models, Bumper To
Bumper Coverage For
1991/92 Models
OPERATION DESCRIPTION TIME
912503A Inspect And Replace Height 1.5 Hr.
Sensor Links
912503B Inspect and Replace Inner 3.0 Hr.
CV Joints
912503C Inspect And Replace Height 3.5 Hr.
Sensor Links And Inner CV
Joints
DEALER CODING
BASIC PART NO. CONDITION CODE
3B414 92
OASIS CODES: 304000, 703000, 703200