Brake Noises and Other Things

[JoeB]

Hey Guys, I'm new to the board so forgive me if I haven't found information on this topic posted in this 3800 forum. I've looked through the entire forum, and haven't found anything yet that helps. However I did find a posting about the brakes pulsating. I'll address that in a minute.

I own a 97 GS Regal (SC 3800). It has been wrecked unfortunately and rebuilt. The previous owner ran it into a culvert turning into his driveway. So the passenger side was damaged and fixed. I did not do the repair. It was already done. I'm suspecting the problem is a result of the crash.

It makes some kind of "crunching noise" at each front wheel when I first move the car. It does this at about 5-10mph, and begins at the driverside, then the passenger side. It just does it about 1/2 second, then stops.

I figured it was the ABS initializing, because sometimes the passenger side doesn't make the "crunching" sound and I will get an ABS error on the dash. Does anyone else have this problem? Has anyone noticed this noise on their Regal? I bled the brake system as directed by a Hanes motor manual. Still got the sound, and random ABS light problem.

Sencond, I'm getting some vibration in the brakes around 60-30. I put brand new rotors on the car, but they were the cheap ones from Autozone instead of GM. I checked the runnout with a dial indicator on each rotor and found that I was getting about .010" to .015" of wobble. I took them to NAPA and had them turned which did improve the runnout measurement, but not the pulsating brake problem. Now the runnout only measures .003"-.005" and it still pulsates the pedal. It's gotta be these stinking rotors, don't you think?

Love this forum. Glad I found it. Oh yeah, I'll have to go dig up my time slips from Bowling Green Raceway. My car is all stock, which I plan to change soon, but first I want to get this brake problem fixed. Seems like my car ran a 15.40 at 91 mph back in November of last year. Definitely not up to par with the rest of you hot rods yet.

 

[neverenuf]

JoeB,

I also have a 97.5 GS and it does the same thing. I haven't had the car that long and am still trying to figure out what it is. Mine does not show the ABS warning though. I have change all rotors and pads and it still does it. I thought it might be something with the axles, although I have no idea. Hopefully someone in the know will enlighten us.

 

[JoeB]

Darren,

Well at least I don't feel alone. I just took apart the left front axle/wheel/steering knuckle/CV joint this past weekend. My intentions are to replace the anti-lock sensor located on the steering knuckle. Or so I thought.

Unfortunately the sensor is mounted to the hub, and has to be purchased as one assembly. If you go in NAPA or Autozone asking for a anti-lock brake sensor they won't know what you are talking about. Ask for the hub. Then you'll get what you want.

At GM cost is $399 for the assembly. At NAPA it's $176. Haven't checked at Autozone yet.

It's my hunch that this particular side is the one that is causing the error to light the ABS signal up on my dash. I always hear the driver side "crunch," but sometimes the passenger side doesn't initialize or crunch, and that's when I get my error. I realize my hunch could be wrong, but without a diagnositc machine I have to do it the old fashioned way,...by human senses.

I'll let you know if this new sensor still makes the same sort of noise. If so, I guess it's just meant to be. But, I don't really care about the noise, it's the ABS light that gets me.

Oh yeah, I've decided to replace the drive axle on that side too. It was $97.00 tax and freight from NAPA. I figured since I was getting a little vibration under acceleration it would probably be a CV joint. Sure enough. The outer joint is a little worn. Hope that fixes it.

Joe

 

[neverenuf]

Joe,

I am going to run this by the guys over on regalgs.org and see if they have any ideas. I am almost afraid to find out the truth and as long as everything works I tend to "not" hear funny noises if you know what I mean

 

[TriShield]

Are you absolutely sure it's the brakes?

The 'crunch' noise could very well be the front struts, I have had a similar noise emanate from the front ends of both my '92 LeSabre and '96 Park Avenue when they are cold.

The sounds disappear after driving awhile.

You may want to consider lubing parts of the struts.

 

[JoeB]

Thanks for the tip, but I would think the movement of the car body along the road would cause a noise from a strut or a spring to occur.

My noise was coming from each front wheel from when I first started the engine and began to move the car. I truly believe it's the ABS sensor making the "scratching/crunching" noise. I'll tell you why.

Before I replaced the ABS sensor (which is unfortunately sold with the complete hub assembly unit), I would sometimes get a noise from the passenger side and sometimes I wouldn't. When I didn't get the noise, the ABS light, the Brake light , and the Service Engine Soon light would come on the dash (guess it was trying to tell me something was wrong.) When ever I did get the noise from both sides everything was fine. The driver side has never failed on creating that noise.

After I replaced the sensor, I get the "scratching/crunching" noise everytime (fingers crossed) from the passenger side. Since the car was hit on that side, I figured the sensor might be bad.

There were all kinds of warnings against installing the hub assembly with an impact wrench. I guess direct vibrations to the hub/bearing surface are bad for the sensor. Needless to say, I used a torque wrench when putting everything back together. It looks like if this was the case, you wouldn't won't the tire shop using an impact wrench on the front wheels either. Just a thought.

Have a good day, and thanks for all the helpful tips guys.