Need advice regarding problem following pad and rotor change
03-28-2007, 03:22 PM
#1
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Thread Starter
Need advice regarding problem following pad and rotor change
Hey guys,
I replaced my front rotors and pads with a zimmerman/mintex red box combo on the front of my 99 c2 tip. I took care to properly bed in the new pads and rotors, and did no hard stopping for the first 200 miles. I've noticed a possible problem, however, and wanted to get the board's feedback.
I hear a rythmic squeaking when I am NOT applying the brakes. Applying the brakes causes no sounds (even though I reused my old vibration dampners). It is almost as though there is a high spot on the rotor that causes a chirp each time this spot on the rotor passes the pad. Lately, the chirp is sounding more like a bad but subtle crunch each time the spot on the rotor passes the pad. The sound is definately connected to wheel speed as it increases in frequency as I speed up, and I can only really hear it when a car is next to me or I am next to a barrier or in a parking garage.
When I took the wheel off to investigate, the only thing I noticed was that the resistance between the pad and rotor was much greater than it used to be. Of course, there was some drag on the rotors before I changed pads on rotors, but it is much greater now (I have to use some real effort to turn the wheel when it is off the ground). I have almost exactly 900 miles on the new pads and rotors. 90% of this is freeway commuting miles. Any help would be great.
I replaced my front rotors and pads with a zimmerman/mintex red box combo on the front of my 99 c2 tip. I took care to properly bed in the new pads and rotors, and did no hard stopping for the first 200 miles. I've noticed a possible problem, however, and wanted to get the board's feedback.
I hear a rythmic squeaking when I am NOT applying the brakes. Applying the brakes causes no sounds (even though I reused my old vibration dampners). It is almost as though there is a high spot on the rotor that causes a chirp each time this spot on the rotor passes the pad. Lately, the chirp is sounding more like a bad but subtle crunch each time the spot on the rotor passes the pad. The sound is definately connected to wheel speed as it increases in frequency as I speed up, and I can only really hear it when a car is next to me or I am next to a barrier or in a parking garage.
When I took the wheel off to investigate, the only thing I noticed was that the resistance between the pad and rotor was much greater than it used to be. Of course, there was some drag on the rotors before I changed pads on rotors, but it is much greater now (I have to use some real effort to turn the wheel when it is off the ground). I have almost exactly 900 miles on the new pads and rotors. 90% of this is freeway commuting miles. Any help would be great.
03-28-2007, 03:31 PM
#2
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Originally Posted by ScottArizona
Hey guys,
I replaced my front rotors and pads with a zimmerman/mintex red box combo on the front of my 99 c2 tip. I took care to properly bed in the new pads and rotors, and did no hard stopping for the first 200 miles. I've noticed a possible problem, however, and wanted to get the board's feedback.
I hear a rythmic squeaking when I am NOT applying the brakes. Applying the brakes causes no sounds (even though I reused my old vibration dampners). It is almost as though there is a high spot on the rotor that causes a chirp each time this spot on the rotor passes the pad. Lately, the chirp is sounding more like a bad but subtle crunch each time the spot on the rotor passes the pad. The sound is definately connected to wheel speed as it increases in frequency as I speed up, and I can only really hear it when a car is next to me or I am next to a barrier or in a parking garage.
When I took the wheel off to investigate, the only thing I noticed was that the resistance between the pad and rotor was much greater than it used to be. Of course, there was some drag on the rotors before I changed pads on rotors, but it is much greater now (I have to use some real effort to turn the wheel when it is off the ground). I have almost exactly 900 miles on the new pads and rotors. 90% of this is freeway commuting miles. Any help would be great.
I replaced my front rotors and pads with a zimmerman/mintex red box combo on the front of my 99 c2 tip. I took care to properly bed in the new pads and rotors, and did no hard stopping for the first 200 miles. I've noticed a possible problem, however, and wanted to get the board's feedback.
I hear a rythmic squeaking when I am NOT applying the brakes. Applying the brakes causes no sounds (even though I reused my old vibration dampners). It is almost as though there is a high spot on the rotor that causes a chirp each time this spot on the rotor passes the pad. Lately, the chirp is sounding more like a bad but subtle crunch each time the spot on the rotor passes the pad. The sound is definately connected to wheel speed as it increases in frequency as I speed up, and I can only really hear it when a car is next to me or I am next to a barrier or in a parking garage.
When I took the wheel off to investigate, the only thing I noticed was that the resistance between the pad and rotor was much greater than it used to be. Of course, there was some drag on the rotors before I changed pads on rotors, but it is much greater now (I have to use some real effort to turn the wheel when it is off the ground). I have almost exactly 900 miles on the new pads and rotors. 90% of this is freeway commuting miles. Any help would be great.
check your dust guards for rubbing
03-28-2007, 03:41 PM
#3
Race Car
Can you identify whether the noise is from the back of front? If from the back, it may be your brake shoes rubbing. See if noise changes while lightly applying parking brake.
03-28-2007, 03:47 PM
#4
Rennlist Member
Thread Starter
Great suggestions. 1999Porsche911, are you asking whether the sound is coming from the front or rear of the front brakes, or whether the sound is coming from the front brakes or rear brakes? Also, and please forgive my stupidity, but what exactly is a brake shoe? Whatever it is, I'll check it. Thanks again.
03-28-2007, 03:53 PM
#5
Race Car
Originally Posted by ScottArizona
Great suggestions. 1999Porsche911, are you asking whether the sound is coming from the front or rear of the front brakes, or whether the sound is coming from the front brakes or rear brakes? Also, and please forgive my stupidity, but what exactly is a brake shoe? Whatever it is, I'll check it. Thanks again.
Noise from back brakes or front brakes. The emergency (parking brake) consists of brake shoes and a drum. The drum is actually the inside of the back brake discs and the shoes press against the inside of the drum to hold the wheel tight when the parking brake is applied. The disc must be removed to ave access to the shoes. These often rub and is not a big deal if it is not too annoying for you. Or, you can take the time and remove the back disc and adjust the shoes.
03-28-2007, 05:12 PM
#6
sounds like the dust sheild rubbing its easy to bend when your doing brakes
figure out which side it is and use a scre driver againts the rotor to push it away fro omthe rotor
figure out which side it is and use a scre driver againts the rotor to push it away fro omthe rotor
03-28-2007, 05:23 PM
#7
Rennlist Member
Thread Starter
Thanks brad, is the dust sheild to which you refer the rubber piece that seals the caliper pistons, or is it something else? Please excuse my inexperience. You guys are great.
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03-29-2007, 01:49 AM
#8
Instructor
Originally Posted by ScottArizona
Thanks brad, is the dust sheild to which you refer the rubber piece that seals the caliper pistons, or is it something else? Please excuse my inexperience. You guys are great.
03-29-2007, 03:30 AM
#9
Three Wheelin'
Hi Scott, I'm sorry to hear that you are also having problems after your brake job. I got so disgusted with mine that I finally bought OEM pads and new vibration hardware from the dealer. The OEM pads have counter weights on the top, unlike the Mintex. The OEM pads (front only) were about $120 and the new vibration dampeners were about $9 each.
The mechanic that has my complete trust at the dealership told me that the vibration dampeners can not be reused. After looking at the new ones, I see why. They have adhesive on the back so that they adhere directly to the back of the pad. Considering how inexpensive they are, you might try replacing those dampeners. It took me about 15 minutes per wheel to swap both the dampeners and the pads. If I can be of assistance, please give me a call. Good luck.
The mechanic that has my complete trust at the dealership told me that the vibration dampeners can not be reused. After looking at the new ones, I see why. They have adhesive on the back so that they adhere directly to the back of the pad. Considering how inexpensive they are, you might try replacing those dampeners. It took me about 15 minutes per wheel to swap both the dampeners and the pads. If I can be of assistance, please give me a call. Good luck.
03-29-2007, 01:48 PM
#10
Rennlist Member
Thread Starter
Thanks guys. I'm going to examine the dust sheild and then spring for some dampners (can you believe that porsche north scottsdale wants 17 bucks each...their prices are insane).
03-29-2007, 02:00 PM
#11
Race Car
Sounds caliper related being that the pads are dragging the rotor, I would take off the rotor and see if the pistons move back and forth smoothly, they should. Of course they are hard to move since you are returning fluid back to the resevoir but it can be done with your fingers. If not maybe use a pry bar and gently (dont damage the pads) push them inward to see if they are hanging. They should move with firm resistance but smoothly, not notchy.
03-29-2007, 02:03 PM
#12
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If it's not the shield, I would bet it's the fact that you re-used the old dampeners. A cheaper alternative to porsche dampeners - Weltmeister Anti-squeal Liners - makes pad changes far easier too.
No affiliation, just a satisfied user.
No affiliation, just a satisfied user.
03-29-2007, 10:12 PM
#14
Rennlist Member
Never heard front or rear wheel? If above does not help set up a homemade dial gauge to check the trueness of the offending rotor. In addition to the above it could be a bad rotor, rust between the rotor and hub (always clean with a wire brush), wheel bearing? Good luck.