This is driving me nuts. I can't drive with the windows down anymore. My brake pads were only about a year old when they started squealing a few months ago. So I tried sanding them a bit and adding CRC Disc Brake Quiet. No joy. I tried a few hard stops, nothing. I even installed new rotors and Posi-Quiet ceramic pads. They still squeal!! What in the world is causing this??

 

Usually, vibration of the pads themselves creates the harmonics that cause squealing, and the noises they make are clearly not music to your ears.

Since you changed out the pads and rotors, you also need to shim the back of the pad (between the piston and the metal plate of the pad). If you can't add a teflon shim, use high temp grease. That's the source of your problem 99.9% of the time.

Avoid the chemical stuff like CRC. It's not going to be a long term solution.

Best of luck and let us know the result please.

 

I also tried high temp grease on the old pads to no avail. I'll try adding the teflon shims on the new ones.

Edit: I'm having a hell of a time trying to fine teflon or rubberized shims sold separately. Any tips on where to find them?

 

I looked in my garage. I don't have any laying around. Usually come with the pads though some manufacturers just include the grease anymore.

You might try calling the manufacturer or try Jagbits. They indicate on their site that they carry them.

 

You may want to try different pads. Ceramic pads can be very hard and tough on rotors, although they do keep the dust down. You may want to try higher end replacement pads that are not ceramic and see how that works for you. Most auto supply stores sell OEM, silver level; premium, gold level; and ceramic pads. I would try the gold level pads.
RyeJag

 

I suspect you have something very basic wrong. Perhaps the wrong pads sold to you? Are you absolutely positively sure you have the anti rattle springs and they are installed correctly?


The correct Jag pads often come with an installed shim and you use anti seize grease and never silicone.


Another thought. Your car has Brembos? Check that one of the pistons is not frozen.

 

Brake squeal is caused by the micro oscillations of release and grabbing of the pad against both the piston, and the external caliper housing. First, insure brake pads have the proper shims, usually covered with some vibration reducing coating, and anti-rattle springs are installed properly. Most brake squeal is found at the piston side pad. Start there. If you can find no other method to reduce squeal, you can use Permatex spray that places an adhesive coating on the backside of the pad. I do not recommend this method. Better to install pads that have the proper shims to remove squeal.

 

I agree with tarheelcracker, the calipers out to be checked out. There is a good possibility that the caliper is not operating correctly. Well worth checking before anything else.


RyeJag

 

Thank you all for your suggestions. I'll dig into them further and report back.

 

I had semi-metallic pads that were quiet for a year until just recently. Then I replaced them with ceramic Posi-Quiets, which have excellent reviews, and while the squealing is definitely reduced, its still there.

No, my car has the standard brakes. What would be the best way to check if a piston is frozen? I would think removing the caliper and pressing the brake pedal would do it? If one doesn't push out, its frozen?

Both sets of pads had just the metal backing plate, with no grease. I tried applying CRC Disc Brake Quiet and grease to the hold pads and it didn't work.

 

Do let us know how this turns out. Don't leave us hanging.

 

I will definitely update when I have a chance to tear into it again.

 

I have the standard disc brakes on my 2004 XJ8; they have continued to chirp (aka: squeal or squeak) even after the installation of new pads and rotors over one year ago. I replaced the rear rotors with Bosch rotors from O'Reilly Auto Parts. I replaced the front rotors with Centric rotors from Amazon. I replaced all brake pads with Wagner Thermo-Quiets. The front pads were somewhat different than the originals; they did not have a groove in the center of the pads. I cleaned all the parts and installed per the factory service manual. One of the rear calipers was a bit stubborn; it required a lot of force to turn the the caliper back in with the proper caliper tool. Despite this straightforward installation of new pads and rotors, I still have brake chirp. The brakes still chirp at all speeds and at separate corners of the vehicle. I've found both of the passenger side brakes chirp almost all of the time, and possibly the front driver brake from to time. It's very annoying. Turning the vehicle one way or the other, silences the chirping momentarily, as if the pad is slightly pulled off the rotor. At this point, all I can confirm is that the installation of new pads and rotors did not resolve the issue. I will post again, if and when I have a solution. Does any of this information prompt feedback from anyone? I'm tempted to simply replace all the brake parts again, including calipers, with oem specified parts from the dealer. But I don't want to go that route, if somebody has resolved this issue more specifically. It would be disappointing to replace all of the parts and find that wheel bearings or other components can also be the culprit. I also suspect that proper adjustment of the parking brake and bleeding of the brakes could play a role. Thanks for any continued feedback on this thread.

 

Have you checked out the caliper pins for smooth operation and no excess play? Have you cleaned and lubricated the guide pins and slide points? The rear caliper should have slid over the caliper freely when installing. If it was tight you may want to readjust the rear calipers once again and reinstall. lastly, there is a compound that you can put on the back of the pads that puts a thin rubber like coating on the back of the pads


Bleeding the brakes should have not be required.


RyeJag

 

Pads without shims will produce the issue you speak of. Just sayin'


http://www.rimmerbros.co.uk/Item--i-C2C23786


There is a pic with what you should see on the back of the pads.

 

Ok, so I've just finished tearing into the brakes again. I cleaned and lubed the slide pins and pistons, blasted everything else with brake cleaner, and coated the metal backing plates on the pads with the spray formula of CRC Disc Brake Quiet. I'm letting the pads dry for a few hours before I do the test drive. Will report back with the results.

 

My container of CRC Disc Brake Quiet states "not for use with shimmed pads". Do I recall correctly that your pads were shimmed?
It seems to me that when I last did my 05 XJR with Brembos that the pads were shimmed. In any case I have never used the CRC product on my Jags as the manual says to use anti seize grease.
Whatever the case one hope it all sorts out for you this time as "you can't be doing dis all day every day" .

 

Well, everything was nice and quiet for about 10 minutes. Back to square one.

 

Could there be a problem with your "bedding In" technique?

 

The instructions for these pads said not to perform any bed-in, just to take it easy for a few hundred miles, which I did. But when they were still squealing after that initial break-in period, I did try to perform some bedding-in procedures. Since the noise actually started with my old set of pads/rotors, I'm led to believe the problem lies somewhere within the car's actual brake components. I cleaned and lubed everything so I don't know what could be the cause.