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Brake Rotor Smoothness?


Impulse

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I was inspecting my brakes today while refilling with air and i noticed circular grooves/etches on the surface of rear right brake rotor. When i ran my nails across the surface of the rotor, they would dig into the grooves, so its not just a color difference. There is not just one, but many of these grooves on the rotor, some deeper and wider, others thinner and shallower like the other rotors.

I decided to checked this because the back of the car emits a loud squeek (like metal on metal) whenever i use the handbrake to slow the car. Ive heard it a few times already stopping myself while rolling down or up a hill.

 

the other rotors are all alright though, not too smooth, not too rough, but none have the deep circular etches as the back right rotor does...

 

is this normal? or should i have the dealer take a look at it?

 

thanks

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I decided to checked this because the back of the car emits a loud squeek (like metal on metal) whenever i use the handbrake to slow the car. Ive heard it a few times already stopping myself while rolling down or up a hill.

 

You use the handbrake while rolling?

 

I use the handbrake to hold my car on a hill when starting, but I wouldn't pull it when the car is rolling... seems dangerous.

 

Anyway, the handbrake is a drum brake inside your rear rotor so it's independent of your grooves.

 

Post a picture.

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you probably just got a small pebble or some sand in your pads

take the pads out clean them off and than rough up the surface and you shuld be good to go unless the groves are very large on the rotor

oh and stop using your e-brake while moving

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Guest *Jedimaster*
you probably just got a small pebble or some sand in your pads

take the pads out clean them off and than rough up the surface and you shuld be good to go unless the groves are very large on the rotor

oh and stop using your e-brake while moving

 

I have a nice deep groove on one of my front rotors-looks like a good sized rock got in there and stayed for a bit.

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I dont see how a rock could get in there?? I dont think there is anything in the mechanicals or hydraulics of the system that would make a gap between the rotor and the pads??

 

Pull off both sets of pads and inspect, run across sand paper and reinstall. If somethings looks wrong upon inspection, replace the pads.

 

The surface of all rotors should be similar.

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Funny, I have the exact same problem with my right rear rotor - the service manager said "a rock must have got in there" but no rock was found by them.

 

When I had the wheels off to rotate the tires, I pulled the caliper off to check for damage to the pads (When I've had rocks stuck in brakes before, the pads show it). The pads were perfectly smooth. I'm thinking that the crappy stock pads just chewed up the rotor. I tried to get the rotor replaced under warranty, but the dealer can't/won't do anything about it until the car starts vibrating under braking.

 

I figure I'll get the rotor turned when I replace the brake pads. At worst, I'll buy a new rotor. What else can I do?

 

-Ryan

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Guest *Jedimaster*
What's weird is when they delivered the car and I first drove it, there was a grinding from the brakes-they took it apart and did find a rock in there- I had it documented just in case. The rotor looked brand new and shiny at that point- over the summer I noticed that there was a groove cut into the rotor fairly deep- couldn't have been from that first day though, right?
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What's weird is when they delivered the car and I first drove it, there was a grinding from the brakes-they took it apart and did find a rock in there- I had it documented just in case. The rotor looked brand new and shiny at that point- over the summer I noticed that there was a groove cut into the rotor fairly deep- couldn't have been from that first day though, right?

 

Hmm, perhaps that's what happened to my car? I bought my '05 in November '05 with ~100 miles on it, and who knows what happened in that first 100 miles? I'd think there would still be visible damage to the pad tho...

 

Mattszeto, I'd have the dealer check it out, or if you're feeling adventurous you can check it out yourself like I did. Do you get any vibration under heavy braking?

 

-Ryan

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:whore:

 

I think a rotor would own a rock...unless your driveway is crushed Kryptonite.

 

not crushed kryptonite, diamonds and adamantium. You should see some race brake pads, they have a consistency of concrete which can EAT rotors if they are not warmed up to operating temperatures.. some of the Hawk Track Pads like the blues or DTC-70s (NASCAR blend) can eat iron-based rotors when cold.

Keefe
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Rocks can certainly get caught in the caliper area. Now I've heard some awful car noises in my day, but the noise a rock makes as it scrapes against a rotor is one of the worst...nevermind the fact how unbelievably loud it is.

 

I've got little grooves here and there across the rotor... I'd only be worried if there was one deep one that didn't have the look or feel of the others.

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hey guys, thanks for the response, as for the vibration under braking, i dont think so , not really. ive only really used the breaks very hard a few times (~8k miles) and haevnt noticed vibration, if any at all. theres also no problem or vibrations when i brake normally for cars, stoplights, ect ect, but then again that wheel is the farthest from me, so i'm not sure if i would be able to feel slight vibrations. and i guess i'll stop using the handbrakes when i'm rolling down hills a bit, i usually use it after i stop on an uphill for a red and roll back a bit before i apply the hand brakes to hold me down. i do this cause theres LOTS of SUVS up here and they tend to get right up to my bumper on the uphills. usually if i roll back down a hill a few inches, they get the idea and stop creeping closer.

 

i will pop the wheel off today and take a look at the pads themselves, perhaps run some 500(or 300?) grit sand paper across them and put them back on. i originally thought a pebble might have caused that too, but then i realized that there is ALOT of pressure applied during breaking, probably enough to crush anything softer than the pads themselves.

another thing i was thinking was that it may be a simple inconsistiency with the pad or the rotor, because it hasnt really gotten bigger since ive first noticed it a month ago after painting my calipers. i first thought it was paint and didnt worry about it, thinking that the pads would scrape it off. but last i checked, paint dosent leave grooves on metal...

 

thanks for the hlep, i'll try to get you guys some pictures today. been busy a bit lately, ive started my third year in physics and boy is it hard...

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Redneck coffee????

 

http://www.hawkperformance.com/motorsports/compounds/index.php

 

DTC-70

Extremely high torque with aggressive controllable initial bite. Superior release and torque control characteristics. Brake pads designed for cars with high deceleration rates with or without down force.

 

DTC-60

High torque with less initial bite than DTC 70. Superior release and torque control characteristics. Brake pads designed for cars with high deceleration rates with or without down force. Recommended for use with DTC-70 when split friction between front and rear axle is desired.

 

DTC-30

Brake pads designed Specifically for Dirt Circle Track applications. Uniquely controllable torque with smooth consistent feel and bite. Superior Release and torque control characteristics.

 

DTC-05

Developed specifically to meet the demands of lower torque Dirt Track Racing. This friction formulation provides very controllable, higher temperature

performance as compared to stock pads.

 

HT 14

Very high torque with aggressive initial bite. Excellent modulation and release

characteristics. Brake pads designed for cars with extremely high deceleration rates and down force.

 

HT 10

Intermediate to high torque with a smooth initial bite. Very consistent pedal feel. Excellent modulation and release characteristics.

 

Blue 9012

Medium/High torque and temperature compound with excellent brake modulation. #1 selling brake pad material for SCCA.

 

Blue MT 4

Medium/High torque and temperature compound with Medium/High initial bite. Brake pads designed for circle track cars under 2800 lbs without high deceleration rates.

 

Black

Medium torque and temperature compound designed to be a good, all-purpose low- cost racing brake pad.

 

DR 97

Excellent static and dynamic coefficient of friction. Smooth linear torque. Low pad and rotor wear. Brake pads specifically designed for use in drag racing applications.

 

 

http://www.hawkperformance.com/motorsports/applications/nascar.php

NASCAR Applications:

DTC-70, DTC-60, HT 15, HT 14

Keefe
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