Brake Noises

[Mountaineerfan 44]

Just stirring up some conversation here, as I think I know what to do (as this isn't my first rodeo).

I recently (5 months ago) replaced my rotors on my front disc factory car.  At the same time I installed EBC Greenstuff brake pads.  I followed the break-in procedure.

For the last month, I have noticed that the left front system is grinding when I push hard on the brakes (coming to a stoplight).  During normal braking, there is no noise.  I checked the pads and rotors, and there is no scoring, and nothing obvious that would be causing the sound.  When I put them back together, I noticed all seemed to be well.  Went to the Tail of the Dragon last week and noticed as the brakes would heat up, the grinding noise returned.  I don't have any vibration occuring, and I'm still able to stop, it's just REALLY loud!  

I've decided tonight I'm taking the system apart again and inspecting everything and replacing the pads (assuming I find nothing else obvious) with Raybestos ceramics to see if the pads just aren't working right for some reason.

Any ideas as to what I need to look for?  Dust shield rubbing?   Calipers flexing?

[RPM 1,190]

I have a sqeak coming from somewhere behind the front seats. After much investigation I found if I turn up the stereo real load the sqeak goes away. 

[Ridge Runner 1,112]

Having similar problem on my 2005 GT ,i get a noise like disks on a brake machine being turned from the rear brakes  . I have checked everything and it all looks good ,calipers do not appear to bind ,no un even wear ,just a bit annoying 

[Mountaineerfan 44]

See that edge of the rotor? It appears the caliper is flexing under heavy pressure and touching the new rotor. How do I stop the caliper from flexing? I can grab the caliper and move it slightly, which makes me think something is loose, but what? 

[det0326 179]

You say new rotor u mean new after upgrade or it is the upgraded one. Check the dia. of that rotor where it is rubbing, may be a little over size. If not u may have to Clearance the caliper where it is rubbing a bit.   

Calipers are a bit loose without any pressure applied. 

Edited March 17, 2023 by det0326
so I am not accused of being a hillbillie that I am.

[Mountaineerfan 44]

New rotor, not caliper. The passenger side seems fine. Since it’s not affecting the pads or braking surface, should I just run it through it’s paces to smooth out on its own?

[Ridge Runner 1,112]

That could aslo be my problem ,i will have to look for that 

[RPM 1,190]

2 hours ago, det0326 said:

 If not u may have to Clarence the caliper where it is rubbing a bit.    

Brahahaha. Airplane. 

[det0326 179]

Wondered why my laptop kelp wanting me to capitalize Clarence. Long story about that word, hahaha good catch Professor Bob 

[Rich Ackermann 174]

I'm guessing you already know this, since you have replaced the rotors. The 70  to 73 Factory Calipers are a floating design. They are held loosely in place on two pins with a rubber boot over each pin to keep the caliper from rattling. Spraying brake cleaner, Gumout, or other solvents dissolve these rubber boots which makes the caliper looser to the point where it may rattle when not applying the brakes, and possibly come in contact with the rotor on the front side when applying the brakes. Try replacing the rubber boots if they are old, worn-out or damaged. You can get them at NAPA for a few bucks. 

[Mountaineerfan 44]

4 hours ago, Rich Ackermann said:

I'm guessing you already know this, since you have replaced the rotors. The 70  to 73 Factory Calipers are a floating design. They are held loosely in place on two pins with a rubber boot over each pin to keep the caliper from rattling. Spraying brake cleaner, Gumout, or other solvents dissolve these rubber boots which makes the caliper looser to the point where it may rattle when not applying the brakes, and possibly come in contact with the rotor on the front side when applying the brakes. Try replacing the rubber boots if they are old, worn-out or damaged. You can get them at NAPA for a few bucks. 

I am WELL acquainted with those boots!  I chased a rattling front-end noise for YEARS, tightening everything I could get a wrench on, replacing everything rubber I could find.  Finally, someone here mentioned to me to check those insulators, and lo and behold all of them were missing!!  What a pain!  Since this was my first Mustang, I didn't know that they were supposed to be there!  So yes, those have been replaced!  

Is it possible that the pins are sticking slightly, causing the flex in the caliper?  I lubed them when I replaced the brakes, but maybe not good enough.  I also had to take a razor blade and puncture the end of the boot, because the suction was causing me problems removing the pins.

[det0326 179]

On 3/15/2023 at 6:51 PM, Mountaineerfan said:

New rotor, not caliper. The passenger side seems fine. Since it’s not affecting the pads or braking surface, should I just run it through it’s paces to smooth out on its own?

My bad, I must have had my head up my rear that day. Could you not just grind a bit off the caliper where the rotor is rubbing or is it in a place where u can't. I would check the dia. of that rotor tho because if it is  a little oversize that would be an easy fix.