Suspension - Front Suspension Knock During Quick Braking
L-SB-0023-12April 5, 2012
Front Suspension Knock Noise During Quick Brake Application
Service Category
Suspension
Section
Front Suspension
Market
USA
Applicability
Introduction
Some 2WD LS model vehicles may exhibit a knock/clunk noise from the front suspension during quick application of the brakes. This is usually most noticeable while driving at parking lot speeds. Follow the repair procedure in this bulletin to address this condition.
Production Change Information
This bulletin applies to vehicles produced BEFORE the Production Change Effective VINs shown.
Warranty Information
Parts Information
Required Tools & Equipment
Repair Procedure
1. Conduct a road test to verify the condition.
Is the condition duplicated during quick application of the brakes?
^ YES - Proceed to step 2.
^ NO - This bulletin does NOT apply. Refer to the Repair Manual for further diagnosis.
2. Use ChassisEAR(TM) (or equivalent) to ensure the noise is coming from the lower No.1 control arms.
Is the noise coming from the lower No. 1 control arms?
^ YES - Proceed to step 3.
^ NO - This bulletin does NOT apply. Refer to the Repair Manual for further diagnosis.
3. Replace the lower No.1 control arms for both right and left sides.
Refer to the Technical Information System (TIS) applicable model and model year Repair Manual:
4. Perform the following steps to ensure that the new suspension arm bushings are relieved of stress.
A. After installing new arms place the vehicle on the ground (NOT on lift).
B. With the engine idling turn the steering slowly from lock-to-lock 10 times.
5. Check front wheel alignment and adjust if required.
6. Road test the vehicle to confirm the noise is no longer present.