Two Seconds of Frustration!
Thread Starter
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Joined: Nov 2005
Posts: 92
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Two Seconds of Frustration!
My dear corvette family,
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
Burning Brakes
Joined: Oct 2004
Posts: 1,019
Likes: 1
From: Weymouth Dorset
Originally Posted by jrod954
My dear corvette family,
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
I think that is your ABS unit doing a check when you start to move, it's normal dont panic, I used to be able to hear mine until I changed my exhaust
.
Melting Slicks
Joined: Jun 2005
Posts: 3,076
Likes: 83
From: Everyone needs something to believe in, I believe I'll have another beer. Wisconsin
Same here, only happens on key start, never from stoplight or stop sign.
lasts only a few seconds. Had the car to a GM garage, couldn't figure it out, I think it's ABS self test.
lasts only a few seconds. Had the car to a GM garage, couldn't figure it out, I think it's ABS self test.
Burning Brakes
Joined: Oct 2005
Posts: 798
Likes: 116
From: OAKLEY CA
2 second noise
It is your ABS self test, don't worry about it, it's suppose to do that. Your ABS has a compressor that pumps up so that it can release a shot of high pressure air to push the pad away from the rotor. I read somewhere it is 2500 psi if I remember correctly, it takes a lot to push back against the hydraulic pressure behind the pad. Thats also why you don't want to "pump " the pedal during a panic stop like non ABS brakes, the pad is releasing many times per second and you are losing a little air pressure each time. I was told all this a long time ago so perhaps the C4 system is a little different, it wouldn't be the first (or last) time I was misinformed. Perhaps someone with better information wants to chime in.
Burning Brakes
Joined: Oct 2005
Posts: 798
Likes: 116
From: OAKLEY CA
Originally Posted by steelblue shark
Same here, only happens on key start, never from stoplight or stop sign.
lasts only a few seconds. Had the car to a GM garage, couldn't figure it out, I think it's ABS self test.
lasts only a few seconds. Had the car to a GM garage, couldn't figure it out, I think it's ABS self test.
Drifting
Joined: May 2005
Posts: 1,370
Likes: 1
From: Raleigh NC
Does your car have the adjustable (Tour, Sport, Performance) suspension option. My car does the same sound and I believe it is the suspension adjusting itself when you initially crank the car. My car usually does it when I'm backing out of my driveway.
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Thread Starter
Advanced
Joined: Nov 2005
Posts: 92
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Guys: I found this website that addressed my concern.
http://www.corvettebuyers.com/c4vettes/prepurchase.htm
Drive the vehicle and observe for unusual sounds or lack of response. (You will hear the ABS system cycle and see a yellow caution light flash on 1987 and later models when you first move the car. This is the normal testing of the system by one of the computers. If you don't see this happen on 1987 and later models, there is something wrong with the ABS system).
Thanks again for all your help!
http://www.corvettebuyers.com/c4vettes/prepurchase.htm
Drive the vehicle and observe for unusual sounds or lack of response. (You will hear the ABS system cycle and see a yellow caution light flash on 1987 and later models when you first move the car. This is the normal testing of the system by one of the computers. If you don't see this happen on 1987 and later models, there is something wrong with the ABS system).
Thanks again for all your help!
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Originally Posted by jrod954
Guys: I found this website that addressed my concern.
http://www.corvettebuyers.com/c4vettes/prepurchase.htm
Drive the vehicle and observe for unusual sounds or lack of response. (You will hear the ABS system cycle and see a yellow caution light flash on 1987 and later models when you first move the car. This is the normal testing of the system by one of the computers. If you don't see this happen on 1987 and later models, there is something wrong with the ABS system).
Thanks again for all your help!
http://www.corvettebuyers.com/c4vettes/prepurchase.htm
Drive the vehicle and observe for unusual sounds or lack of response. (You will hear the ABS system cycle and see a yellow caution light flash on 1987 and later models when you first move the car. This is the normal testing of the system by one of the computers. If you don't see this happen on 1987 and later models, there is something wrong with the ABS system).
Thanks again for all your help!
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by ED HEISER
It is your ABS self test, don't worry about it, it's suppose to do that. Your ABS has a compressor that pumps up so that it can release a shot of high pressure air to push the pad away from the rotor.
You've got to be kidding, right?
Nothing like that on my C4.....
Larry
code5coupe
Race Director
Joined: Apr 2004
Posts: 17,066
Likes: 3
From: Milpitas ca
Originally Posted by jrod954
My dear corvette family,
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
I have a noticeable noise coming from the rear end, but only at start-up. It doesn't matter if I go forward or reverse the noise lasts about 2 seconds and then goes away. I noticed it only occurs when I initially start the car and move. It is more of a grinding noise. I took everyone's advice and lubricated the axle nuts and retorq'd to factory specs, but that didn't solve the problem. Is this just a normal noise from the abs/asr that I should get used to? There isn't any noticeable clunking noise when driving the vette ('93 coupe) and I visually inspected the u-joints. I would think if if was the u-joints it would do it while driving - not just when I start the car and drive.
