[xxpaulcpxx]

Actually, this is more of a general problem. I replaced the pads and lathed the rotors on my Kia Minivan a few months back, now they are starting to squeek annoyingly. What causes brakes to squeek in general?

 

[ComposiMo]

I'm under the impression that it is more vibrations causing the sound, whcih is why the anti-squeak backing plates, and sprays and stuff that you apply to the back of the pad in some cases work so well... Dunno, other than with some racing pads, i've never had 'normal' pads squeak on me <shrug>

 

[Krix]

Because its a Kia? :lol: j/p 8)

 

[rex2nr]

^ thats what I was thinkin

 

[ollie]

OK here goes...I will do my best to answer this one.(although I'm rather surprised John didnt.)

As we all know brakes use clamping force to squeeze pads together against a rotor(in disc setups anyway).This causes friction and heat.
In a properly working brake system the pad is designed to apply force(friction) to the rotor and dissipate heat all at the same time.(at the expense of wear to the pad lining)
Now I say all that to help you understand the next.
A squeak occurs in most instances when the pad resonates(like a tuning fork) in the caliper.
This happens because the pad surface is compromised in some way.(Mostly moisture).
A wet rotor will actually lubricate the pad surface and the pad can vibrate because it cant "grab" the rotor properly.
Actually if you want to get technical a brake pad is designed to work at a certain temperature.Thats why racers cycle or warm up their brakes before a heat.Ever notice that cold brakes can squeak and seem to be a little weak?
Oh and another situation that can cause a squeak is if the pad lining is "glazed".Glazing occurs when pad material is actually transferred to the rotor(kinda like burned in)and contaminates the brakes.This situation is fixed by replacing the pads and machining the rotors.
I hope my little 5 minute explination helps ya Paul.
If I can ever help ya just ask.
I know that there are other instances that cause a squeak,but that covers 90% of them.

 

[iLLA]

I've also been wanting to undertand this....good info.

 

[Dren]

And another thing...not to be an ass...but It's called turning or turning down the rotors, not lathing the rotors. You may catch some **** from machinists for asking them to lathe you up something. :wink:

 

[toxiclows]

I am going to go with my best possible answers on this one...

... Cheap pads... . oraganic cheapo pads tend to squeak more than metallic or semi metallic pads do... not sure if it is just there cheaper compound that does it... or the fact that they make more brake dust.. which would do it as well

..... glazed up pads... fi the pads are glazed you will be able to pull them off and go over them with some sand paper and knock the glaze off.. and then give the rotor a light scuff.... though this will just be a temp fix i would imagine...

No anti squeak compound on the back of the pads or no anti squeak shims...

also a sharp edge on the facing and trailing end of the pad... you can file down a cheapo pad that is not made this way and improve it... and take that sharp edge off... If you look at the good pads you will see that most all of them have these beveled edges and anti squeak shims on them. . ..

 

[toxiclows]

oooh,,,, I just had another thought... . . might want to make sure that your back brakes are adjusted up all the way... if they are down and not doing alot of braking for ya then that is going to but more braking demand on the fronts and possibly be overheating the pads and rotors causing premature glazing.. . .

just a thought.

 

[88DXCRX]

And another thing...not to be an ass...but It's called turning or turning down the rotors, not lathing the rotors. You may catch some [crap] from machinists for asking them to lathe you up something. :wink:

Also commonly known as "machining the rotors"..on a brake lathe.

One thing that causes it is "harmonic resonance"
created by the outer lip of the rotor that the pad doesn't cover...

Ever rubbed your damp finger around the rim of a wine glass?
Basically the same principal..

It can also be cause by the pad vibrating against the pad holder
or the caliper piston itself....
You might try some "Disc Brake Quiet" sold at NAPA..
It is like a glue that sticks the pads to the caliper and pad holder.

If the pads came with "shims" for the back sides of pads,
Check to see if they are loose..I usually just toss them..
They can cause more problems than they solve.

 

[logix_xxii]

squeaks are caused by vibration but there are also other reasons like for example if it's first thing in the morning there may be rust on the rotor that can cause it also glazing on the rotor when it gets real shiny a method that i use that i usually have good luck with is to use antiseize yes spark plug antiseize read the bottle it's first listed use is for brakes just put some on the back of thepads where they meet the caliper

 

[ComposiMo]

Wow... way to dig deep! 8) :lol:

Welcome to the site!

 

[coz]

removed

 

[logix_xxii]

preciate it man not diggin to deep though just what i do for a living i work at pepboys i was a mechanic there but made a stupid decision and took a pay raise for another position it's all good though the moneys better any ways if u know chemik personaly then u will probably get to know me been friends for a real long time