K 2500 Truck 4WD V6-262 4.3L VIN Z TBI (1995)
Brake Drum: All Technical Service Bulletins
Rear Brakes - Howl/Moan
File In Section: 5 - Brakes
Bulletin No.: 56-50-10A
Date: May, 1996
Subject:
Rear Brake Howl/Moan Noise (Replace Brake Drums)
Models:
1995 Chevrolet and GMC C/K 2500 Models
with JB7/JD7 Brake Systems and 9.5" Rear Axles
This bulletin is being revised to include drawings of C/K model rear axle covers so that dealer personnel can more easily identify trucks equipped with
9.5 " axles. Please discard Corporate Bulletin Number 56-50-10 (Section 5 - Brakes).
Condition
A howl or moan noise emanating at the rear of the vehicle may be noticed under a moderate brake pedal application. The noise is most noticeable at low
speeds near the end of a stopping maneuver.
Cause
Normal vibrations produced during braking may approach the resonant frequency of the brake drums.
Correction
The current 13 x 2.5" brake drums should be replaced with 13 x 3.5" brake drums (P/N 15960224). The larger brake drums have a different resonant
frequency which should eliminate the moan/howl noise. Refer to Figure 1 to determine which axle is used in your customer's truck.
Service Procedure
Replace the brake drum as described in Section 4B1 of the 1995 C/K Service Manual.
Parts Information
