Squealing from brakes, but it goes away

[BagOfWalnuts]

So over the summer I noticed that my brakes are squealing, so I figured, ok time to replace the pads. But what i noticed is that they only do it after the car has been sitting for a long time (i.e. overnight, or while I'm at work), and they only do it for about the first minute I'm driving. It also seems to happen more on humid days...could it just be condensation or something on the brakes?

 

[CRXican]

happens sometimes, mine were squeaking today but had them checked recently and the pads are at least 75% life

have them looked at just to be sure

 

[Gibson486]

4 wheel disc brakes?

It's common. Even on ceramic brakes, there are still metal shavings. On my Mazda, sometimes you would hear this loud squeal when you back up (loud enough for people across the people to notice).

 

[Arcanedeath]

Brake rotors are iron and they rust while sitting and it takes awhile to clean them off and get rid of the small layer of rust / oxidation that builds up after they have been siting awhile and this is generally what causes the noise but once you've scraped that layer of oxidation off the noise goes away.

 

[pcgeek11]

Brake rotors are iron and they rust while sitting and it takes awhile to clean them off and get rid of the small layer of rust / oxidation that builds up after they have been siting awhile and this is generally what causes the noise but once you've scraped that layer of oxidation off the noise goes away.

This! Surface rust. No worries.

 

[SpatiallyAware]

Even though it's common you can usually get rid of it by taking the pads out, cleaning everything, and using a couple dabs of the disc brake glue on the back of your pads.

 

[pcgeek11]

Even though it's common you can usually get rid of it by taking the pads out, cleaning everything, and using a couple dabs of the disc brake glue on the back of your pads.

That isn't going to help with the surface rust on the Rotor Surface.

 

[SpatiallyAware]

That isn't going to help with the surface rust on the Rotor Surface.

Even though surface rust can cause some initial squealing, it's often exacerbated by the adhesive for the shims deteriorating. If it's a 'regular' car with normal rotors then reapplying it fixes the squeal most of the time.

 

[dave_the_nerd]

I had a car that would squeak after going through puddles.

 

[hanoverphist]

mine has more of a grind sound than a squeak. i really need to get them changed.

 

[MotF Bane]

Surface rust, don't worry about it.

 

[thescreensavers]

Even though surface rust can cause some initial squealing, it's often exacerbated by the adhesive for the shims deteriorating. If it's a 'regular' car with normal rotors then reapplying it fixes the squeal most of the time.

Glue? adhesive? I am pretty sure its a lubricant

 

[SpatiallyAware]

http://www.crcindustries.com/auto/content/prod_detail.aspx?PN=05016


If you change the pads on a brand new brake system you'll see that the metal shims behind the pads are lightly glued in place by the factory.

Generally new pads from regular parts stores skip the shims altogether and go with a thicker backing plate...

I'm not sure why, but the shims being slightly loose is enough to cause things to squeak/squeal... I actually just helped a friend with an '08 sentra w/ 30k where the dealer etc etc could never get the squealing to go away. It used to only happen when cold for a few min after driving (similar to OP) but after putting a little dab of the disc brake quiet stuff between the pad and shims every noise is gone (along with cleaning up the pads, rotor area etc). The dealer told her the same crap.. It's surface rust blah blah..

I've done this on at least 5-6 cars with great results.. High performance brakes it doesn't make much of a difference, any type of commuter or regular car it does.


Edit: BTW, the spray on stuff sucks and doesn't work for long at all. Get the orange thick goop like I linked..

 

[SpatiallyAware]

Glue? adhesive? I am pretty sure its a lubricant

The brake grease is ok, but in my experience needs reapplied after a few months.

The orange goop dries to almost a rubber substance. I apply it very lightly, about two dime sized thin drops after cleaning everything. Put it back together, start car, apply brakes firmly to squeeze everything together and then let sit for a few hours to dry. Voila, no more squealing.

 

[thescreensavers]

The brake grease is ok, but in my experience needs reapplied after a few months.

The orange goop dries to almost a rubber substance. I apply it very lightly, about two dime sized thin drops after cleaning everything. Put it back together, start car, apply brakes firmly to squeeze everything together and then let sit for a few hours to dry. Voila, no more squealing.

Which grease have you used? If you apply too much it can get squeezed out. I used Sil Glyde, las week so I wonder how it will work in a few months. I do know the stuff that dealer put on my car was crumbling when I cleaned it off, so I have no idea what they used. hopefully there isnt an issue.

 

[SpatiallyAware]

Which grease have you used? If you apply too much it can get squeezed out. I used Sil Glyde, las week so I wonder how it will work in a few months. I do know the stuff that dealer put on my car was crumbling when I cleaned it off, so I have no idea what they used. hopefully there isnt an issue.

I don't know the brand, I usually go for full syn or otherwise high quality stuff.

Per most service manuals you are supposed to use grease only if you have 'floating shims'... Otherwise you should use the goop.


Note that I am not talking about the 'guiding arms' on the pads, or the sliding pins... I'm talking about a couple of dabs between the pads, the shims, and the caliper.