2006 STS4 Squeaking Sound when slowing
 

2006 Cadillac STS4 w/ Northstar V8

Discussion:

When slowing or stopping there is a squeaking sound in the front suspension.

Details:

This is a very rickety sound much like what one is used to in an old pickup or work truck.

The sound reacts when slowing down in a parking lot/garage as the car rolls over speed bumps.

The sound goes away when the car is driven through a car wash with an undercarriage sprayer and sometimes in the rain.

When the sound is audible it is coming from both sides of the front end.

Troubleshooting up until now:

Visual inspection -- I have visually inspected all of the front suspension from a-arms to shocks and all look normal w/o leaks or tears in grease joints.

The car has slotted and drilled rotors -- I visually inspected the breaks as well as tearing them apart and cleaning all surfaces. (This noise was not apparent when I first installed the new brakes and factory pads)

The research I have conducted shows that the control arms do go bad and have to be replaced, however, this noise is not a clunk and the joints all appear good.

Ideas:

I believe this to be a lack of grease in the anti-sway bar bushings. Before I tear the bushings off of the Cadillac I am open to comments and information from those who are/might be familiar with this issue.

Please only respond to this post if you are familiar with this problem.

Thanks,
D.

Hackneyd

I had the same problem on my 07 STS. I posted the problem back in Aug 08. It was a defective lower control arm. Bushings were shot. Car sounded like an old buggy going down the road.

Eddiek

Thanks Eddiek, the left lower control arm was the problem. I changed it out last weekend with a new part from GM, (P/N:25862781). This is an updated part from the original equipment and it looks like the busings have more material then that of the original's.


Here is the procedure for the lower control repair.

Additionally you will need these tool sizes:

18mm socket and wrench
21mm socket (deep well) and wrench
24mm socket (deep well)
Set of metric allen wrenches


This article has been updated by TSB Bulletin No. 06-03-08-006

Date: May 17, 2006

SERVICE MANUAL UPDATE

Subject:
Revised Front Lower Control Arm Ball Stud Retaining Nut Fastener Tightening Specification

Models:
2003-2006 Cadillac CTS, SRX, STS

Lower Control Arm Replacement

Tools Required

• J43631 Ball Joint Remover

Removal Procedure

1. Raise and support the vehicle. Refer to Vehicle Lifting.
2. Remove the tire and wheel.
3. Remove the shock module yoke.

1. Remove the stabilizer shaft link lower retaining nut.
2. Remove the stabilizer shaft link from the lower control arm.
3. Remove the ABS wire harness from the lower control arm.

1. Remove the lower control arm to steering knuckle nut.

1. Using the J43631, separate the lower control arm from the steering knuckle.

1. Loosen the power steering gear retaining bolts and raise the power steering gear. Important: Will need to raise the power steering gear to have clearance when removing the rear lower control arm to frame retaining bolt.

1. Remove the lower control arm to cradle nuts.
2. Remove the lower control arm to cradle bolts.
3. Remove the lower control arm by lowering the lower control arm at the frame and moving the ball stud upwards.

Installation Procedure

1. Install the lower control arm by installing the lower control arm on the ball stud and moving the lower control arm up to the cradle.
2. Install the lower control arm to cradle bolts.
3. Install the lower control arm to cradle nuts. Tighten the nuts to 135 Nm (96 ft. lbs.) . Notice: Refer to Fastener Notice in Service Precautions.

1. Tighten the power steering gear retaining bolts. Tighten the bolts to 120 Nm (89 ft. lbs.) .

1. Install the lower control arm to steering knuckle nut.

1. Tighten the nut to 40 Nm (30 ft. lbs.) .
2. Tighten the nut to an additional 120 degrees .

1. Install the ABS wire harness to the lower control arm.

1. Install the stabilizer shaft link to the lower control arm.
2. Install the stabilizer shaft link lower retaining nut. Tighten the nut to 110 Nm (81 ft. lbs.) .
3. Install the shock module yoke.
4. Install the tire and wheel.
5. Lower the vehicle.
6. Align the front end. Refer to Measuring Wheel Alignment.

Strutmasters for your suspension problems
 

Take a look at Strutmasters conversion kits. These kits change your air suspension into a coil suspension. Best of all they come with a lifetime warranty. You want have suspension problems again.

Glad I could help. Based on the procedure, I'm glad mine was covered under warranty.

Eddiek