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Disc Brake's squealing noise


I drive a 2001 Nissan Pathfinder. it has front disc brake and rear drum brake. I recently replaced the brake pads for front brakes. i didn’t work/replace the rotors because they did not look worn out. After driving for about 3-4 weeks, i started hearing the squealing noise when braking at low speed (15-20 mph, braking to a complete stop). I then took the front wheels out to inspect for proper installation and normal wear and tear on the pads. The pads still looked like brand new (these are factory pads). Could you advise on what other things i could try? Many thanks.

The problem is failing to surface or replaced the rotors. As they wear, the outer diameter wears faster than the inner diameter. The surfaces are no longer parallel. The new pads will no longer have solid contact on the front and back. The gap allows for the vibration which is the squealing. You have to get the rotors resurfaced/replaced. And you may have to replace the pads again because of uneven wear from being used against the worn rotors.

You don’t have to replace the rotors every time you replace the pads. The new pads will bed to the old rotors just fine. The pads may have come with anti-squeal plates, which are installed between the pad backer and the caliper. If not, you can get anti-squeal compound from the parts store.

I think you want to work the brakes kind of hard once you put on new pads to get them bedded. Was there a little tube of grease to put on the back side of the pads (the side opposite the rotor)?

Disc brake squeal is probably the number 1 “after brake job complaint” it is also probably the reason most shops insist on some type of rotor work. If you had had your work done at a shop and the brakes started squealing, the shop could not charge you for whatever it takes/took to eliminate the squeal.

Spreading different products on the back side of the pad probably has about a 10% chance of working. I have used a product that we spread on the front (friction) side of the pad and the re-installed the pads, this technique worked about 1% more than the former.

Most likely you are going to have to make some changes in the rotor surface.

all, thanks for your advice. After reading all of the responses, i thought i would take the least expensive approach. I bought the disc quiet compound and sprayed on the back side of the pads yesterday. the squealing noise has come to a minimal. thanks again.

The rotor surface plays an important role in preventing brake noise when new pads are installed. Along with the proper precedure to get the brake pads to embed into the rotors. You can read about it here.


The backyard method is replace pads only. The proper procedure is to always service the rotors. The latter is the only way to assure with reasonable certainty the new brakes do not become noisy. Sometimes, even that is not etched in stone.

If you install new rotors you should thoroughly clean the rotors with Brake Kleen or a carburetor cleaner such as B-12. Many rotors have a rust preservative film that must be removed first. Sometimes this film is noticeable and sometimes it’s not.
New cast iron can also have an inherent amount of oil impregnated into the metal. Cleaning them first will take care of most of this possibility.