Brakes Are Squeaking !

[Grandpa]

Hey guys, I changed my front rotors + brakes, but there is this problem that persists. My front brakes squeal(no shims) when I'm driving, even when I don't press the brake. It doesn't start squealing until 10-15 minutes into driving and it'll squeal without me pressing the brakes at all... I've oiled/greased the clips and when I checked the brakes, it looked like there was uneven wear on JUST one side of ONE pad(the outside pad). Any suggestions? I hope i don't have to overhaul the boots

[LScott400]

If the outside pad is wearing faster, then the caliper is not sliding/floating as it should on the caliper bolts. They need to be pulled, cleaned, inspected (should be smooth and uniform), replaced if needed, lubed and reinstalled.

For the squeal I would recommend getting the OE shim kit and fitting kit (springs and clips). The fitting kit is specifically for anti-squeal purposes. While pads are removed, rough up the friction surface (just rubbing it around on the concrete will do). I also lightly file the 90 degree edges off at an angle. Since calipers are unlikely to sit at a perfect 90 degree angle to the rotor this allows the pads to wear in at the angle they will ride at regularly without sharp corners contacting the rotor causing a squeal.

Best wishes!

[Grandpa]

If the outside pad is wearing faster, then the caliper is not sliding/floating as it should on the caliper bolts. They need to be pulled, cleaned, inspected (should be smooth and uniform), replaced if needed, lubed and reinstalled.

For the squeal I would recommend getting the OE shim kit and fitting kit (springs and clips). The fitting kit is specifically for anti-squeal purposes. While pads are removed, rough up the friction surface (just rubbing it around on the concrete will do). I also lightly file the 90 degree edges off at an angle. Since calipers are unlikely to sit at a perfect 90 degree angle to the rotor this allows the pads to wear in at the angle they will ride at regularly without sharp corners contacting the rotor causing a squeal.

Best wishes!

So if the pad on the outside is wearing faster, that wouldn't be the cause of squealing?

[LScott400]

Sure, it could be glazed from running on the rotor all the time. Roughing up the pads to break the glaze and cleaning/lubing or replacing the caliper bolts may be all that's needed.

[Grandpa]

Sure, it could be glazed from running on the rotor all the time. Roughing up the pads to break the glaze and cleaning/lubing or replacing the caliper bolts may be all that's needed.

Alright, but what does lubing the bolts do?

[LScott400]

Caliper bolt wear or corrosion prevents the free movement of the caliper housing or brake pads causing premature pad wear. If the caliper housing is not free to move on its mounting pins the outboard brake pad will not release completely.

Rust in the caliper casting holes is a common cause of this problem. In the casting holes the rust “grows” causing the inner diameter of the casting hole to “shrink”. This causes the rubber bushing or boots to be squeezed tightly around the caliper mounting pins and restricting free caliper movement. Rust may be more or less of a problem depending on your part of the country.

[SKperformance]

You need to remove the sliders and wire wheel them then reinstall them using slider grease.

So many DIY guys change brakes thinking it is only pulling off parts and throwing new ones on.

When changing the pads/rotors you have to clean and grease the slider pins if it is floating and lube the inside of the piston boot . You should also remove and flush a small amount of fluid that sits behind the pistons as it is where most air and bad fluid sit.

[Grandpa]

You need to remove the sliders and wire wheel them then reinstall them using slider grease.

So many DIY guys change brakes thinking it is only pulling off parts and throwing new ones on.

When changing the pads/rotors you have to clean and grease the slider pins if it is floating and lube the inside of the piston boot . You should also remove and flush a small amount of fluid that sits behind the pistons as it is where most air and bad fluid sit.

eh.... is there a tutorial for this cause I'm not sure what a slider is -_-

[LScott400]

Here you go!

Steps 7, 10 & 16 in particular.

[Grandpa]

alright... so what is most likely the problem that is causing the squealing since it doesn't start until 10 minutes after driving(no squealing during the braking + driving period of 10 minutes).

[nc211]

That says to me that your slider pins are sticking as already mentioned. Your pad is dragging on disc enough to heat it up as you drive, and then eventually squeak due to the constant friction. I think you have your answer to your question. Your pad is dragging, probably due to dirty slider pins on the caliper housing. It's not a difficult proceedure to fix at all. Any shop can clean and grease them for you in no time at all.

[LScott400]

Jul 22 2006, 09:55 PM "My front brakes squeal(no shims) when I'm driving, even when I don't press the brake. It doesn't start squealing until 10-15 minutes into driving and it'll squeal without me pressing the brakes at all... I've oiled/greased the clips and when I checked the brakes, it looked like there was uneven wear on JUST one side of ONE pad(the outside pad). "

Jul 23 2006, 11:02 PM "So if the pad on the outside is wearing faster, that wouldn't be the cause of squealing?"

Jul 24 2006, 11:18 AM "Alright, but what does lubing the bolts do?"

Jul 25 2006, 03:37 PM "eh.... is there a tutorial for this cause I'm not sure what a slider is"

Jul 25 2006, 07:55 PM "alright... so what is most likely the problem that is causing the squealing since it doesn't start until 10 minutes after driving(no squealing during the braking + driving period of 10 minutes)"

The answer to your last question is my response to your first question. If what you really want to know is "why" that will involve research on how noise(squeal) is created by vibration, resonance, the effect of temperature change on resonance and the material properties of different friction materials.

[Grandpa]

Ahh.... ok, I decided to do the slider pins myself (sorry for all the questions and constant requestioning). The slider pins were a little sticky, but I just took a towel and sprayed a little wd-40 to remove all that gooey stuff, then let it air dry and reapplied some brake grease. When I went to install it, I pushed both of the pins in as far as possible and pulled the boot over that little elevated area( i hope that's how you isntall it ) and then just tightened the piston assembly back onto the unit.

[LScott400]

Hope that works for you! If you still have squeal, then next step would be to get pad shim kit from Lexus.

[Grandpa]

Since Im doing the fron left tire... where does the slider pin with the indentions on the rubber go? towards the front of the car or in the rubber housing area closer towards the back of the car? ( i didn't notice a difference between the slider pins and I dont get what lexls.com is saying)

[LScott400]

I think the pins are the same. The bushings for the pins are supposed to be different, but I couldn't tell from his pics. I haven't changed pin bushings, so I'm not familiar with these. Sorry :(