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Turd Furgusson
Samba Member
Joined: May 25, 2009
Posts: 136
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 Posted: Fri Jul 20, 2018 9:23 am Post subject: Loud drilled rotors |
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Has anyone tried these rotors: https://www.jbugs.com/product/22-3853-B.html?gclid...q0QAvD_BwE
And notice how loud they are? Not the squealing, but like a hissing
sound when you hit the brakes? I put them on new with the recommended
semi metallic pads. Will the sound die down some? |
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Eskamobob1
Samba Member
Joined: August 08, 2016
Posts: 541
Location: South OC SoCal
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| Posted: Fri Jul 20, 2018 9:28 am Post subject: Re: Loud drilled rotors |
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I haven't tried those specifically, but even when installing with the anti-squeal grease on the back of the pads brand new rotors often squeal for a little bit. Have you set the pads yet? Often a real world heat cycle will help quite a bit with the sound.
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'74 - front disks/lots more work to do |
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Turd Furgusson
Samba Member
Joined: May 25, 2009
Posts: 136
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| Posted: Fri Jul 20, 2018 9:49 am Post subject: Re: Loud drilled rotors |
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| They don’t squeal...it’s a hissing sanding noise...I used the disc brake grease on the back of the pads. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12854
Location: North Carolina
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| Posted: Fri Jul 20, 2018 10:22 am Post subject: Re: Loud drilled rotors |
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Umm, that's what they're gonna do. You just bought cheese graters for your brake pads.
The cross drilling/fire slotting not only gives the gasses that build up between the pad & rotor upon extreme braking somewhere to go but they also give the brake pad a fresh surface with each pass. Hopefully they put enough forethought into the drilling pattern so that you don't end up with parts of the pad that don't get "cleaned", this will leave you with high & low spots on the pads & decreased braking ability.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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sawed off
Samba Member
Joined: September 15, 2016
Posts: 428
Location: Idaho
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| Posted: Fri Jul 20, 2018 10:46 am Post subject: Re: Loud drilled rotors |
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| Yes sound should die down some after break in. Semi metalic are rough until seated |
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kangaboy
Samba Member
Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
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| Posted: Fri Jul 20, 2018 12:05 pm Post subject: Re: Loud drilled rotors |
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I have drilled rotors as well...and they never quiet down. I have put a few thousand miles on mine and they are as loud as they day I put them on. I wish I would have known this prior to purchase, because I'm at the point of shopping for standard rotors to replace the drilled ones. So annoying.
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out  |
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Turd Furgusson
Samba Member
Joined: May 25, 2009
Posts: 136
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| Posted: Fri Jul 20, 2018 1:20 pm Post subject: Re: Loud drilled rotors |
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| kangaboy wrote: |
| I have drilled rotors as well...and they never quiet down. I have put a few thousand miles on mine and they are as loud as they day I put them on. I wish I would have known this prior to purchase, because I'm at the point of shopping for standard rotors to replace the drilled ones. So annoying. |
Did you use semi metallic pads? |
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Turd Furgusson
Samba Member
Joined: May 25, 2009
Posts: 136
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| Posted: Fri Jul 20, 2018 1:25 pm Post subject: Re: Loud drilled rotors |
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| TDCTDI wrote: |
Umm, that's what they're gonna do. You just bought cheese graters for your brake pads.
The cross drilling/fire slotting not only gives the gasses that build up between the pad & rotor upon extreme braking somewhere to go but they also give the brake pad a fresh surface with each pass. Hopefully they put enough forethought into the drilling pattern so that you don't end up with parts of the pad that don't get "cleaned", this will leave you with high & low spots on the pads & decreased braking ability. |
I’m pretty sure half of what you said isn’t correct, but thanks for
sharing. |
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kangaboy
Samba Member
Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
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| Posted: Fri Jul 20, 2018 7:02 pm Post subject: Re: Loud drilled rotors |
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| Turd Furgusson wrote: |
| kangaboy wrote: |
| I have drilled rotors as well...and they never quiet down. I have put a few thousand miles on mine and they are as loud as they day I put them on. I wish I would have known this prior to purchase, because I'm at the point of shopping for standard rotors to replace the drilled ones. So annoying. |
Did you use semi metallic pads? |
I'm not sure, mine came in a kit with my Wilwood Calipers. I can look at them tomorrow and reply.
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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Epilog79
Samba Member
Joined: June 04, 2009
Posts: 218
Location: Tigard,Oregon
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| Posted: Fri Jul 20, 2018 9:56 pm Post subject: Re: Loud drilled rotors |
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I have the Topline drilled and slotted rotors and they also make that hissing sound under braking. As you say it is annoying. It’s has been 3 years since I switched to these and the sound has not gone away. Oh well, not going to change now, maybe in the future.
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slalombuggy
Samba Member
Joined: July 17, 2010
Posts: 9147
Location: Canada
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| Posted: Fri Jul 20, 2018 10:35 pm Post subject: Re: Loud drilled rotors |
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| Turd Furgusson wrote: |
| TDCTDI wrote: |
Umm, that's what they're gonna do. You just bought cheese graters for your brake pads.
The cross drilling/fire slotting not only gives the gasses that build up between the pad & rotor upon extreme braking somewhere to go but they also give the brake pad a fresh surface with each pass. Hopefully they put enough forethought into the drilling pattern so that you don't end up with parts of the pad that don't get "cleaned", this will leave you with high & low spots on the pads & decreased braking ability. |
I’m pretty sure half of what you said isn’t correct, but thanks for
sharing. |
Nope. Everything he said is correct. I've put drilled rotors on all sorts of cars with all kinds of pads. Buy a bigger stereo cause they're gonna be noisy for life. They also eat pads faster and usually the rotors are also grooved up after a set of pads are done. 911 C4s destroyed their brakes, when they were done they were DONE.
brad
brad |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12854
Location: North Carolina
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| Posted: Sat Jul 21, 2018 4:16 am Post subject: Re: Loud drilled rotors |
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| Turd Furgusson wrote: |
| TDCTDI wrote: |
Umm, that's what they're gonna do. You just bought cheese graters for your brake pads.
The cross drilling/fire slotting not only gives the gasses that build up between the pad & rotor upon extreme braking somewhere to go but they also give the brake pad a fresh surface with each pass. Hopefully they put enough forethought into the drilling pattern so that you don't end up with parts of the pad that don't get "cleaned", this will leave you with high & low spots on the pads & decreased braking ability. |
I’m pretty sure half of what you said isn’t correct, but thanks for
sharing. |
Yeah, the part where they had enough forethought to actually design the pattern to clean all parts of the pad equally when in all probability they just tossed the rotors in the CNC & let it rip. 
In one of the above pics you can see that the cross drilling in that rotor at least appears to have chamfered edges to decrease the cheese grater effect but you can also see that the swept area of the pad reaches beyond the cross drilling/slotting, this will lead to areas on the brake pad that will be higher that the parts that don’t get cleaned/ground off. These high points will now be the the first to make contact with the rotor & do most of the braking leaving you with far less contact surface area causing decreased braking performance and grooves in the rotors.
And in this pic that the other person posted...
You can already see the phenomenon of which I speak by the darker lines starting at the edges of the cross drilling, this is where the rotor is getting hotter due to an incorrect pattern. The wear/localized overheating would be worse if not for the fire slotting.
Another thing that the chamfering does is that it reduces the tendency of stress cracking in the rotor (especially on a cast iron rotor), but most crappy cross drilled rotors don’t experience this because they’re not used on the track in the extreme conditions that would warrant the actual use of cross drilling & fire/gas slotting. Basically, unless you actually drive the car to it’s limits & have to brake repeatedly to the point of brake fade, you’re just installing these for looks.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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volksworld
Samba Member
Joined: November 26, 2011
Posts: 2529
Location: formerly NY currently NC
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| Posted: Sun Jul 22, 2018 7:51 am Post subject: Re: Loud drilled rotors |
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| the last time i worked for a nascar cup team they had stopped drilling rotors and were only putting the slots in them....and the slots extend all the way to the edge of the rotor or the gasses and dust would be trapped |
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