Are new brake pads supposed to leave a stain on clean cloth?
10-03-17, 02:50 PM
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Are new brake pads supposed to leave a stain on clean cloth?
I have a few pairs of the Shimano J04Cs, which seem to be well received (jensonusa.com/Shimano-J04C-Metal-Disc-Brake-Pads).
However, my problem is constant contamination after about 2 rides, which weirdly almost comes off with only hot water and bit of brushing. Anyway, the pads never seem "clean". They will _invariably_ leave a dark stain on a clean cloth.
I also tried with a brand new pair straight from the package, and same thing.
Is this normal?
However, my problem is constant contamination after about 2 rides, which weirdly almost comes off with only hot water and bit of brushing. Anyway, the pads never seem "clean". They will _invariably_ leave a dark stain on a clean cloth.
I also tried with a brand new pair straight from the package, and same thing.
Is this normal?
10-03-17, 03:43 PM
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I use the same pads and have had zero issues with 6 sets. Is the "contamination" actually causing braking issues like screeching or hindering the stopping power? If not, just leave it alone. It just might be fine dust from the pads and rotors doing their thing, that's why I put contamination in quotes earlier.
Are you touching the pads or rotors with oily hands? Is there excess brake mineral oil or chain lube on the calipers or on the rotor? Wipe the rotors and calipers with 90 proof isopropanol alcohol on a clean rag. I'm real careful to remove the pads for bleeding and not touching the calipers and rotors with dirty hands on install. That's all I can think of if there is true contamination happening. Also, new pads take a bit to break-in for max stopping power--several rides. They might seem like they're slipping for awhile.
Are you touching the pads or rotors with oily hands? Is there excess brake mineral oil or chain lube on the calipers or on the rotor? Wipe the rotors and calipers with 90 proof isopropanol alcohol on a clean rag. I'm real careful to remove the pads for bleeding and not touching the calipers and rotors with dirty hands on install. That's all I can think of if there is true contamination happening. Also, new pads take a bit to break-in for max stopping power--several rides. They might seem like they're slipping for awhile.
10-03-17, 04:27 PM
#3
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I cannot speak for your brake pads, they're quite mute on this,
(supposed, indicates intention, contact the brake pad manufacturer and ask them what they intended)
<guess>Probably aluminum oxide from the rim, deposited on the pads, friction is how you stop, right?
....
....
(supposed, indicates intention, contact the brake pad manufacturer and ask them what they intended)
<guess>Probably aluminum oxide from the rim, deposited on the pads, friction is how you stop, right?
....
....
Last edited by fietsbob; 10-07-17 at 08:51 AM.
10-03-17, 05:01 PM
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The originals mirror the same results as the replacements?
I'm afraid to break the bad news to you about the brakes...
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.
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normal.
Immediately contact your lbs if you have any more doubts though!
I'm afraid to break the bad news to you about the brakes...
.
.
.
normal.
Immediately contact your lbs if you have any more doubts though!
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10-03-17, 08:18 PM
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aluminum dust and road dirt... and if you go riding in the rain, it will drip off the wheels/tires in copious quantities!
10-03-17, 08:35 PM
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10-03-17, 08:46 PM
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FWIW - I think you missed the part where the OP said it was about DISC brake pads.
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10-05-17, 12:58 PM
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I'm still curious if there is actually a braking performance issue or if finding traces of brake dust is only what is bothering the OP. FYI, disc brakes produce brake dust while rim brakes do not. Don't expect disc brake pads to be clean, even after just two rides. On top of producing dust from use, they are porous and will collect it as well. Unless there is oil on the pads or rotors, there is no need to clean. In fact, if oil gets on the pads, good luck getting it out. Rotors can easily be alcohol wiped per my first post.
10-05-17, 01:40 PM
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10-05-17, 02:22 PM
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However, my problem is constant contamination after about 2 rides, which weirdly almost comes off with only hot water and bit of brushing. Anyway, the pads never seem "clean". They will _invariably_ leave a dark stain on a clean cloth..............................................................
Is this normal?
Is this normal?
10-06-17, 09:10 PM
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Relating to the OP
I have taken to a habit of: daily blasting air from the shop compressor between my pads to clean them. Sends a dark puff of brake dust flying.
This doesn't *seem* detrimental, the brakes work fine and feel smooth with no squealing or grinding...
it doesn't seem to be counterproductive to the bed-in of the rotor/pads.
any harm in regularly blowing the brake dust out like this?
might just be confirmation bias, but I feel like they brakes work better than from before I started doing this...
I have taken to a habit of: daily blasting air from the shop compressor between my pads to clean them. Sends a dark puff of brake dust flying.
This doesn't *seem* detrimental, the brakes work fine and feel smooth with no squealing or grinding...
it doesn't seem to be counterproductive to the bed-in of the rotor/pads.
any harm in regularly blowing the brake dust out like this?
might just be confirmation bias, but I feel like they brakes work better than from before I started doing this...
10-07-17, 05:54 AM
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motorcycles and cars have the same design in bigger scale. The operator's/owner's manual doesn't cover it being as an after-use ritual thing.
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