Interior - Road Noise in Passenger Compartment
89cadillac16Bulletin No. T-90-1
File in Group 10
Number 158
Corp. Ref. No. 912001
Date Sept. 1989
SUBJECT: ROAD NOISE IN PASSENGER COMPARTMENT
MODELS AFFECTED: 1989-1990 DE VILLE AND FLEETWOOD SEDANS
Some 1989-1990 DeVilles and Fleetwood Sedans may experience road noise emitting from the rear seat or rear sail panel areas on coarse road surfaces (i.e., worn or stud damaged concrete). This sounds very similar to wheel bearing noise. Follow the procedure below before replacing the hub and bearing assembly.
To repair this condition install dampening package, P/N 25553218 which is currently available from GMSPO, on top of the left and right rear strut towers (inside the rear compartment area) using the following procedure:
1. Remove plastic speaker enclosure from rear shelf, if equipped, and discard. If equipped with Bose speakers, speaker enclosure must be trimmed to provide clearance.
IMPORTANT: Additional trim removal is not necessary.
2. Install one stud extender to the rearmost strut mount stud. Do not remove existing strut mount nuts. Torque to 12-15 N-m.
3. Install left and right dampener masses to the top of the rear shock towers. (Dampeners are marked LH for left and RH for right.)
4. Install washers and M-14 nuts and torque to 20 N-m.
For warranty purposes use Labor Operation T6380 at .3 hour.
IMPORTANT: After installation check driver's door label and verify that GVWR does not exceed 2141 kg (4720 lbs.) total. If GVWR exceeds 2141 kg (4720 lbs.) total, it will be necessary to install aluminum bumper reinforcements, front and rear, to maintain GVMR specifications.
25529356 - Front Bumper Reinforcement, Upper 25529347 - Front Bumper Reinforcement, Lower 25529350 - Front Bumper Reinforcement, Outer RH 25529351 - Front Bumper Reinforcement, Outer LH 25529331 - Rear Bumper Reinforcement Impact Bar 25529328 - Rear Bumper Reinforcement, Outer LH 25529329 - Rear Bumper Reinforcement, Outer RH
Refer to Section 2B in the 1989 DeVille/Fleetwood Service Information Manual. For warranty purposes use Labor Operation B0340 at 1.3 hours-front, and B0940 at .9 hour-rear.