IMBALANCED FRONT TRIM HEIGHT DIAGNOSE/REPLACE FRONT SPRING
SUBJECT: IMBALANCED FRONT TRIM HEIGHT (DIAGNOSE/REPLACE FRONT SPRING)
VEHICLES AFFECTED: 1991-92 "B" MODEL SEDANS WITH BASE SUSPENSION (FE1)
THIS BULLETIN IS BEING REVISED TO INCLUDE 1991-92 CHEVROLET "B" CAR SEDANS, ADDED REFERENCE INFORMATION FOR P/N 22076504 AND TO REMOVE +/- FROM STEP NUMBER 5. ART WORK REMAINS THE SAME.
APPLICATION:
----------- 1991-92 Chevrolet "B" car sedans with Base Suspension (FE1) 1992 Buick Roadmaster Sedan with Base Suspension (FE1)
CONDITION:
--------- Some 1991-92 "B" car Sedans with base suspension systems, RPO FE1, may exhibit what appears to be a side to side trim height imbalance as viewed from the front of the vehicle. Typically this condition would appear as if the right front corner of the vehicle is lower than the left front corner.
CAUSE:
----- Front spring selection is based on the vehicle mass as seen by the front wheels and a common spring is selected for both front corners of the vehicle, independent of the side to side mass differential.
CORRECTION:
---------- Following procedure indicated below, measure the "A" dimension shown in illustration for both sides of vehicle to determine if spring replacement is required.
SERVICE PROCEDURE:
1. Perform the following checks and make sure:
o Tires are at the correct pressure as shown on the "Tire Placard" "up to vehicle capacity."
o Fuel tank is full.
o Vehicle has no additional weight or passengers.
o Front seat is in rear position.
o Trunk is empty except for the spare tire and jack, and simulated fuel load if required.
o Vehicle is on a known level floor.
o All doors, hood and rear compartment lid are closed.
2. Lift front bumper of vehicle up approximately 38 mm (1-1/2 inch). Gently remove hands and let vehicle settle.
Repeat operation for a total of two (2) times. After the second time, measure "A" dimension.
3. Push front bumper down approximately 38 mm (1 -1/2 inch). Gently remove hands and let vehicle rise on its own.
Repeat operation for a total of two (2) times. Measure "A" dimension.
4. Calculate the average of the two "A" dimensions measured for each side of the vehicle.
5. If the difference between the "A" dimension averages side to side are:
LESS THAN OR EQUAL to 10 mm (.4 inch) of each other, the vehicle is within specification and no further action is required.
MORE THAN 10 mm (.4 inch) of each other, proceed to Step 6.
6. Determine front spring code from tags on either of the existing springs or from the vehicle "Service Identification Label".
7. From chart below select applicable spring code/part number for a spring one load rate HIGHER than existing spring and install spring on lowest front corner of vehicle following applicable Service Manual, Section 3C (Front Suspension).
Service Spring Codes and Part Numbers
Code Part Number ---- ----------- FTH 22076507 Highest Load Rate
FTF 22076506
FTD 22076505
FTC 22076504 Lowest Load Rate (Reference Only, this P/N not serviced by GMSPO)
For vehicles repaired under warranty use:
Labour Operation: E-3020
Labour Time: 0.9 Hr.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
