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Discussion Starter · #1 ·
93 MX6 LS 5 speed NON ABS

I'm running Powerstop cross drilled rotors with axxis brake pads. The rear rotors have recently been shaved and new pads were installed about a month ago. Also the rear left caliper was replaced, it was locking up.

The problem is that whenever I brake, sometimes I hear a rather loud "clunck" when i come to a stop from about 25mph or above. It's a noise like metal hitting metal. This only happens when I brake. Sometimes, I hear a continous clunck when braking. Someting like "puck, puck puck puck".. gradualy slowing as the car slows down. my first thought was that I cracked a rotor. I ripped off all 4 wheels and carefully inspected all 4 brake systems. the rotors and pads seemed fine, no visual problems. I believe the noise is coming from the rear though I didnt hear any noise when I used my e-brake to slow down from 25mph. Also, th ecar seems to be braking in pulses. Meaning that when I press the brake slightly, it feels like it grabs and lets go, grabs and lets go etc. like if th erotors were warped even though th erear ones were just shaved.

I'm trying to find out if it's a rotor problem or maybe something else like the brake lines or the fluid. I still havent checked the fluid but will today. Help me out guys, with the winter snow coming, I'd hate not to have brakes while driving in the snow...
 

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I have the same sort of brake clunk noise, and the car is at Mazda today for a couple of things, so if they fix that problem, I will let you know what it was. I am hoping to get the car back today but it doesn't look like I will be able to because of a stupid meeting I have to go to...damnit i don't want to wait for tomorrow to get the car back...*sigh*

bj
 
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It might not be your brakes, i have that same noise, and it turned out to be the engine mounts on my car were going bad. So i would check the engine mounts
 

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JPMX6GT said:
93 MX6 LS 5 speed NON ABS
The problem is that whenever I brake, sometimes I hear a rather loud "clunck" when i come to a stop from about 25mph or above. It's a noise like metal hitting metal. This only happens when I brake. Sometimes, I hear a continous clunck when braking. Someting like "puck, puck puck puck".. gradualy slowing as the car slows down. my first thought was that I cracked a rotor. I ripped off all 4 wheels and carefully inspected all 4 brake systems. the rotors and pads seemed fine, no visual problems. I believe the noise is coming from the rear though I didnt hear any noise when I used my e-brake to slow down from 25mph. Also, th ecar seems to be braking in pulses. Meaning that when I press the brake slightly, it feels like it grabs and lets go, grabs and lets go etc. like if th erotors were warped even though th erear ones were just shaved.
If you are feeling pulsing, my money would be one warped front rotors, not rear. That "clunking" noise you are hearing is likely the caliper knocking back and forth on its slider pins as the warp goes by the pads. It could also be the pads themselves knocking slightly in their seats due to the warpage.

If you slightly increase braking effort (a bit more pressure on the pedal) does the noise go away?

Help me out guys, with the winter snow coming, I'd hate not to have brakes while driving in the snow...
Clunking noises aren't comforting things to hear but the cause is not likely to lead to a sudden loss of brakes.

See if you can get the trueness of the rotors check while they are on the car (i.e. take the wheel off, torque all the lugnuts back on to 80 ft-lbs and measure the warpage of the rotors with a dial-gauge.)
 

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Discussion Starter · #5 ·
My first inxtinct was on the rotors as well. Actually if anything, I'll just replace them with slotted rotors rather than cross drilled. Still, could there be ANYTHING else that could be causing this problem?

When I removed the wheels, I DID feel the pads rub on certain spots when I turned the rotor. The thing is, the noise is coming from the REAR.. I'm 99.9% sure of it. Could the warping cause this noise in the rear as well?
 

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Slim chance that the clunk is the pads rattling around in the calipers. If when the pads were replaced some of the shims or retaining springs were not put back in, or put in properly, the pads could be loose in the caliper. Causeing a pulse when they "grab" the rotor.

Warped rotors will cause a pulse in the pedal during hard braking at at least freeway speeds. (My car and pedal will shake like it's losing a wheel under hard braking above 100mph).

You can order the hardware for the brakes for less than $15 front or rear.
 

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Mazda fixed my clunk noise, they said one of the calipers was sticking...They also fixed the suspension creak that I have had for about 6 months now, so that's good.

bj
 

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Discussion Starter · #8 ·
Actually I've been running with one less brake pad spring (You know those metal clps that push th epads out) for over a year not and it never caused a problem like this. I'll stop by Pep boys and get one of their generic ones and bend it to fit mine to see if that eliminates the problem. I highly doubt it though but it's worth a shot.

Also, what is th ebest brake fluid that I should use to refill it in case it's low? Redline? Where can i get these puppies?
 

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Autocrossing my car, I've had to flush my brake fluid 3 times in the last 9 months (from boiling the fluid). I just use Penzoil Sythetic. It's pretty good stuff, the only time the brakes would "fluid fade" was when they got hot enough to burn the backs of my hands on the wheels when checking air pressure. Redline would just be too expensive to flush 3 times. The Penzoil stuff has handled antilock braking from 120mph with no fade.
 

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I had the braking clunk also and like bj_swift, I had a sticking caliper. The brake slides have to be re-greased every 12 months. Mine is due for it again and have been looking around for the correct ultra-high temp grease. Normal HT bearing grease will not do.

Trev
 
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