Groan noise. Normal for track pads?
09-27-2012, 02:32 PM
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Groan noise. Normal for track pads?
TLDR: Carbotech brake pads groan very loudly when coming to a slow stop. Not high pitched squeal/screech
I did lots of searching/reading. Most topics cover high pitched squeal that non-bedded, non-shimmed, or non-lubricated track pads make. My noise is not these. Maybe it's normal?
Aside from the typical squeal or screech of track brake pads, I'm getting a very loud low pitched groan coming from my brakes. Someone else in another thread described it as sounding like when you let off your emergency brake after washing your car.
Background:
-Installed Carbotech XP10/XP8 last weekend.
-Drove on them for a few days to hopefully wear off the stock pads' transfer layer.
-Bed-in process yesterday with about 8 stops from 50 to 75 mph. Pedal felt softer and smelled brakes. Freeway drive for about 10 minutes to return home.
-When I exited the freeway after the brake bed-in process, I slowed to the light, all high pitched squeals gone thanks to the bed-in. Braking slowly and silently up to the light, once I hit less than 10mph a very loud GROAN and some vibration was suddenly given off from the brakes (I have not isolated which one(s) yet).
-Today in normal road driving, the brakes were near silent except for the very very loud groan persisted when coming to a slow stop or inching forward in traffic. If I medium/hard brake down to a stop, then the pads remain silent. It is just when coming to slow stop that they groan, and persists even after letting off the brake pedal completely, with car still inching forward.
Is this normal? Is there a way to eliminate the groan? I will probably go in and reseat the pads tonight and make sure the shims (reused stock shims) and brake lubricant are all in proper order. I'll try push the caliper piston even further when putting the pads back in. But I'm quite sure I did it all correctly. Are there any other ideas? Or confirmation that it is indeed an issue with shims?
This groan did not occur before the bed-in process (only the typical very loud squeal), so it is likely a result of the grippier brakes. My hypothesis is it feels like one or more of the pads wants to stick to the rotor when the rotor is moving slowly, but there is enough momentum to push the rotor past that sticking point and make the pad skip on the rotor, causing vibration and noise, rather than allowing it to glide to a stop. It seems there may be some brake drag present, since the groan persists after letting off brakes right before stopping. Also when sitting stopped in neutral not on the brakes, the car has a bit more resistance to roll freely, suggesting there is a bit more friction on the brakes when not applied than I am used to. I understand some drag is normal, and so it may just be accentuated with well bedded track pads, and this groan may just a side-effect of that. Is there another way to reduce this drag (if it is the issue)?
I did lots of searching/reading. Most topics cover high pitched squeal that non-bedded, non-shimmed, or non-lubricated track pads make. My noise is not these. Maybe it's normal?
Aside from the typical squeal or screech of track brake pads, I'm getting a very loud low pitched groan coming from my brakes. Someone else in another thread described it as sounding like when you let off your emergency brake after washing your car.
Background:
-Installed Carbotech XP10/XP8 last weekend.
-Drove on them for a few days to hopefully wear off the stock pads' transfer layer.
-Bed-in process yesterday with about 8 stops from 50 to 75 mph. Pedal felt softer and smelled brakes. Freeway drive for about 10 minutes to return home.
-When I exited the freeway after the brake bed-in process, I slowed to the light, all high pitched squeals gone thanks to the bed-in. Braking slowly and silently up to the light, once I hit less than 10mph a very loud GROAN and some vibration was suddenly given off from the brakes (I have not isolated which one(s) yet).
-Today in normal road driving, the brakes were near silent except for the very very loud groan persisted when coming to a slow stop or inching forward in traffic. If I medium/hard brake down to a stop, then the pads remain silent. It is just when coming to slow stop that they groan, and persists even after letting off the brake pedal completely, with car still inching forward.
Is this normal? Is there a way to eliminate the groan? I will probably go in and reseat the pads tonight and make sure the shims (reused stock shims) and brake lubricant are all in proper order. I'll try push the caliper piston even further when putting the pads back in. But I'm quite sure I did it all correctly. Are there any other ideas? Or confirmation that it is indeed an issue with shims?
This groan did not occur before the bed-in process (only the typical very loud squeal), so it is likely a result of the grippier brakes. My hypothesis is it feels like one or more of the pads wants to stick to the rotor when the rotor is moving slowly, but there is enough momentum to push the rotor past that sticking point and make the pad skip on the rotor, causing vibration and noise, rather than allowing it to glide to a stop. It seems there may be some brake drag present, since the groan persists after letting off brakes right before stopping. Also when sitting stopped in neutral not on the brakes, the car has a bit more resistance to roll freely, suggesting there is a bit more friction on the brakes when not applied than I am used to. I understand some drag is normal, and so it may just be accentuated with well bedded track pads, and this groan may just a side-effect of that. Is there another way to reduce this drag (if it is the issue)?
09-27-2012, 07:58 PM
#2
I wouldn't worry about it. These are just noisy pads (and dusty, and corrosive when the dust meets moisture) especially when cold. It could be partially because there is still some stock pad material hanging around - but I have a set of XP10/8 for track use with dedicated rotors that have only ever seen these pads, and they're STILL noisy as hell on the occasions I drive them on the street. Mine mostly squeak, but sometimes they groan too. You will probably not get rid of the noise with a re-bed, or it will just change the noise.
09-28-2012, 02:47 PM
#5
The groan is NOT normal with properly bedded pads. But that's the reason, you didn't bed them properly.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
09-28-2012, 07:05 PM
#7
The groan is NOT normal with properly bedded pads. But that's the reason, you didn't bed them properly.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
Otherwise, I agree, carbotech's should be bedded in on "clean" rotors.
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09-28-2012, 08:27 PM
#8
Originally Posted by davidc1' timestamp='1348872451' post='22045473
The groan is NOT normal with properly bedded pads. But that's the reason, you didn't bed them properly.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
You can't "remove" the stock pad transfer layer unless you surface the rotor. You can also use a wire brush wheel on a drill to do it, but it takes a long time.
There are several of us that run these pads, including myself and psychoazain, and we have essentially no noise at all on the street or track.
Got to Carbotech website and they'll tell you how to bed them. But you should have received the directions in the box they came in.
Otherwise, I agree, carbotech's should be bedded in on "clean" rotors.
The bed in process I followed was essentially the equivalent of exactly what Carbotech recommends, but adapted for the street since I can't do it at the track. The process was suggested to me by Carbotech. The process was followed by Psychoazain as well, who has bedded in "countless" pads. He's the guy who does the pad reviews on the Competition forum.
The process for the street in essentially 5-8 stops from 40-50 down to 5mph with no cool down, then 6-8 stops from 80-5mph until fading occurs, which is usually when you see sparks shooting out from the pads. This is followed by a ten minute drive with no braking at all (accomplished by driving uphill), and then parking, again without using the brakes at all.
The Carbotech guys said one of the keys is to make sure the pads are bedded on resurfaced rotors and make sure they fade from the high speed stops.
Maybe the reason we can get them to the point they make no noise is because we are able to do all of these successive stops with no other braking at all, because both of us have access to long straight roads with no stop signs at the wrong places.
All of our sets of pads have produced essentially no noise on the street at all except a very slight scrape/squeak that you can barely hear, just before stopping. I concede I may occasionally get a slight groan when the rotors are cold, but that may only be for one or two stops.
10-01-2012, 08:00 AM
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I was following the procedure described here, which is linked from s2ki's library section on DIY Brakes.:
http://www.essexparts.com/learning-c.../swapping_pads
I think a few things were at play here.
Possibly Carbotech's are too rotor friendly, less metallic than other track pads, and didn't scrape off enough of the stock transfer layer during my daily driving. Possibly I just did not drive long enough. Maybe I should have done the process shown in the video rather than the daily driving described in the write-up.
I didn't observe patchy transfer layers as shown in the pictures of that article, it appeared smooth with some bluish hue tinted onto the rotor. But nonetheless there was probably some stock pad layer remaining.
The other thing is that I may have a warped rotor. I'll inspect while swapping back to stock pads this evening. Thanks for the inputs!
http://www.essexparts.com/learning-c.../swapping_pads
I think a few things were at play here.
Possibly Carbotech's are too rotor friendly, less metallic than other track pads, and didn't scrape off enough of the stock transfer layer during my daily driving. Possibly I just did not drive long enough. Maybe I should have done the process shown in the video rather than the daily driving described in the write-up.
I didn't observe patchy transfer layers as shown in the pictures of that article, it appeared smooth with some bluish hue tinted onto the rotor. But nonetheless there was probably some stock pad layer remaining.
The other thing is that I may have a warped rotor. I'll inspect while swapping back to stock pads this evening. Thanks for the inputs!
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