IMBALANCED FRONT TRIM HEIGHT DIAGNOSE/REPLACE FRONT SPRING
SUBJECT: BALANCED FRONT TRIM HEIGHT (DIAGNOSE/REPLACE FRONT SPRING)
MODELS AFFECTED: 1992 BUICK ROADMASTER SEDANS
CONDITION:
Some 1992 Buick Roadmaster Sedans with base suspension systems, RPO FEI, 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:
- Tires are at the correct pressure as shown on the Tire Placard up to vehicle capacity."
- Fuel tank is full.
- Vehicle has no additional weight or passengers.
- Front seat is in rear position.
- Trunk is empty except for the spare tire and jack, and simulated fuel load if required.
- Vehicle is on a known level floor.
- 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 (1-112 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" (located on inner trunk lid).
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 procedures outlined in Section 3C (Front Suspension) of the 1992 Roadmaster Service Manual.
Service Spring Codes and Part Numbers
Code Part Number
FTH 22076507 Highest Load Rate FTF 22076506 FTD 22076505 FTC 22076504 Lowest Load Rate
Parts are currently available from GMSPO.
WARRANTY INFORMATION:
Labor Operation: E3020
Labor 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.
