Brakes: "normal" squealing vs. "change your brake pads!" squealing
03-01-05, 02:11 AM
#1
Advanced
Thread Starter
Brakes: "normal" squealing vs. "change your brake pads!" squealing
Although the dealer used the anti-squeal shim kit or what not, there is still a squealing noise when I apply the brakes ('91 LS00). Dealer said it was normal and nothing to worry about. My question is...will I be able to tell between this "normal" squealing and the low-brake indicator?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
03-01-05, 07:09 AM
#2
Lexus Champion
A couple of times a year, I remove all four wheels, one at a time. I service the drive (axle) shaft rubber boots, inspect the suspension and steering components and visually look at all eight pads for thinkness and uneven wear. The brakes wear slowly and if monitored will minimize surprises. By the time the brake indicators start to squeel, the rotors may be worn too thin to resurface and need replacing with the pads. But if the pads look good and the rotors surfaces seem smooth, a spray of brake cleaner should clean off any excess dust on the brake pad surfaces, resolving the problem till next time they need cleaning.
03-01-05, 09:25 AM
#3
Racer
You are only causing damage to your rotor if the pads wear completely and all that is left is the metal backing plate. At that point, hitting the brakes will grind the backing plate into the rotor, making a distinctive grinding, metal-to-metal noise. The wear indicators should start making noise well before that, and as Tammy says, you can inspect the pads at that point.
03-01-05, 09:44 AM
#4
Don't like the sound of this!
Actually there is no sound. However , when I hit the brakes I can feel a slightly perceptible pull to the right. I cannot actually feel it through the steering wheel ( it is not like alignment ) believe it or not it is easiest just to see the effect. Hood dives down & slightly right if you are really watching for it.
It is as if one caliper is closing later than the other.
damon
It is as if one caliper is closing later than the other.
damon
03-01-05, 06:24 PM
#5
Originally Posted by kreativ
My question is...will I be able to tell between this "normal" squealing and the low-brake indicator?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
the squealing heard from the low brake indicator is when your foot is not on the pedal. The little "finger" vibrates as it drags on the rotor and creates the squeal indicator noise. When you apply the brake pedal, the vibration is halted and the low-brake indicator stops squealing.
no damage is occuring to the rotor, as Perry has said. Should you continue without changing the pads, the squeal becomes a grind and damage is being done.
steviej
03-04-05, 01:38 AM
#6
Advanced
Thread Starter
Originally Posted by steviej
the squealing heard from the low brake indicator is when your foot is not on the pedal. The little "finger" vibrates as it drags on the rotor and creates the squeal indicator noise. When you apply the brake pedal, the vibration is halted and the low-brake indicator stops squealing.
no damage is occuring to the rotor, as Perry has said. Should you continue without changing the pads, the squeal becomes a grind and damage is being done.
no damage is occuring to the rotor, as Perry has said. Should you continue without changing the pads, the squeal becomes a grind and damage is being done.
03-04-05, 08:20 AM
#7
Lexus Champion
Originally Posted by kreativ
Although the dealer used the anti-squeal shim kit or what not, there is still a squealing noise when I apply the brakes ('91 LS00). Dealer said it was normal and nothing to worry about. My question is...will I be able to tell between this "normal" squealing and the low-brake indicator?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
When you hear the brake pad indicator, you still have some pad left so no damage is done to the rotors.
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04-01-05, 04:38 PM
#8
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Originally Posted by kreativ
Although the dealer used the anti-squeal shim kit or what not, there is still a squealing noise when I apply the brakes ('91 LS00). Dealer said it was normal and nothing to worry about. My question is...will I be able to tell between this "normal" squealing and the low-brake indicator?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
On a related note, by the time you can hear the low-brake indicator, are you already causing damage to the rotor?
Did he put the anti-squeal greast on the shims? otherwise its still metal to metal.
04-02-05, 04:58 AM
#9
Lexus Fanatic
Originally Posted by kreativ
Didn't know that! How does the "finger" come in contact with the rotor if you foot is not on the pedal?
and as the pad wears down the finger gets closer and closer to the rotor
until it hits and gives you a squeal
and if you let that go it becomes a grinding noise
which usually means hello new rotors and pads
04-02-05, 05:01 AM
#10
Lexus Fanatic
Reader Question: I just had my disc brakes replaced and they are now squealing. My mechanic says this is normal, why did I have to pay for normal squealing disc brakes? Is he just blowing me off?
Dear concerned car owner,
This unfortunately can happen more than you or I want it to. A certain amount of high-pitched brake noise is considered "normal" these days because of the harder semi-metallic disc brake pads that are used on cars now. In my experience, the smaller cars like Honda and Toyota seem to have the most trouble with this. Squeals heard the first few stops in the morning when the brakes are cold and somewhat damp from dew, and squeals that are heard the last few feet while coming to a stop are usually nothing to worry about.
Semi-metallic brakes are made of bits of metal shavings in place of the asbestos material that has been banned by the U.S. government. These semi-metallic brakes have great stopping power and have a long wear life, but can cause a high-pitched squeal that drives car owners crazy and frustrates mechanics who can't get it to go away to please their customers.
When are squeals not a problem?
Some brands of semi-metallic pads are inherently noisier than others because of the ingredients used in the manufacture of the friction material. Think of it this way, the longer life pads or pads that claim to have more stopping power usually contain more metallic material. Yes, they will last longer and could enhance braking but the chance of causing a squeal noise is very high. The squealing noise that might be caused from use of these pads does not affect braking performance and does not indicate a brake problem.
Brake squeal is caused by vibration between the brake pads, rotors, and brake calipers. Having the brake rotors refinished or trued (machining a small layer of the metal away from the disc brake rotor to make it smooth and "true" again) and a thin layer of a silicone compound placed on the back of the brake pads are a great way to reduce the squeal if the semi-metalic pads are the culprit of the noise and not due to a worn out disc brake pad.
Why does this squeal happen anyway?
The brake rotor is the round metal object that the brake pads squeeze together like the white part of an Oreo cookie. The rotor is metal and has a smooth slick finish, and the brake pads are made of metal shavings and also have a smooth somewhat slick finish. The more metallic material found in the pad the greater the chance for noise, and vise-versa.
The other type of brake pad is called organic. There is no metallic material used in this kind of brake pad. Organic style brake pads can only be used on vehicles that are specifically designed to use them. Improper use of organic pads on a vehicle designed to use semi-metallic can severely reduce stopping ability. Organic pads are softer than semi metallic and usually do not have a squeal problem. Unfortunately due to shorter life expectancy, inability to stop larger vehicles, and the addition of substances like asbestos in their construction, they are not very widely used.
When are squeals signaling a problem?
Sometimes brake squeals are an indication that maintenance is required. Some common conditions that cause brake noise are:
*
Heat cracked or worn "un-true" rotors
*
Rough finish on resurfaced rotors
*
Loose fitting brake pads in the brake calipers
*
Lack of silicone compound on back of brake pad
*
Missing springs or anti-rattle clips that should be on the caliper or pad
*
Improper tightening sequence of lug nuts or caliper hardware
*
Contamination on the brake pad i.e. brake fluid
Most GM cars are equipped with a small thin piece of metal attached to the brake pad to act as a warning indicator when the pad material is getting low and the brake pads should be replaced. This inexpensive warning device can be deceiving though, because this warning noise is present when the brakes are not depressed. When the brakes are applied, the warning noise goes away because the indicator has now been forced against the brake rotor and is not able to vibrate which causes this whistling noise.
If you hear brake noises other than a squeal, it could mean your brake pads are worn out and need to be replaced. If your brake pedal feels different than normal or if you've noticed any change in the way your vehicle brakes (pulls to one side when braking or requires more pressure on the brake pedal), or loss of brake fluid have the brake system inspected at once.
What should I do?
What can you do as a customer to reduce the chance of squealing brakes? First of all, noisy brakes should always be inspected to make sure there isn't a problem with the braking system. If the pads have worn down to the point where metal-to-metal contact is occurring, your vehicle may not be able to stop safely, and you may damage the brake rotors or drums to the point where they have to be replaced. Sometimes a few harder-than-normal stops can "de-glaze" the brake pads and help reduce the squealing noise for a while.
There are many aftermarket brake pads that claim to be "quiet" or have been "designed" for import and front wheel drive vehicles that you can choose from. Personally, I have had the best luck replacing the disc brakes on small vehicles like Honda and Toyota with original equipment pads from the dealership rather than using aftermarket brands. It is usually more expensive to purchase these pads from the dealership, but the quality is much better. I am an independent shop owner and my whole business philosophy is to buy as little as possible from dealerships, but after trying many squealing aftermarket brake pads, I have learned my lesson and pay the extra money.
Dear concerned car owner,
This unfortunately can happen more than you or I want it to. A certain amount of high-pitched brake noise is considered "normal" these days because of the harder semi-metallic disc brake pads that are used on cars now. In my experience, the smaller cars like Honda and Toyota seem to have the most trouble with this. Squeals heard the first few stops in the morning when the brakes are cold and somewhat damp from dew, and squeals that are heard the last few feet while coming to a stop are usually nothing to worry about.
Semi-metallic brakes are made of bits of metal shavings in place of the asbestos material that has been banned by the U.S. government. These semi-metallic brakes have great stopping power and have a long wear life, but can cause a high-pitched squeal that drives car owners crazy and frustrates mechanics who can't get it to go away to please their customers.
When are squeals not a problem?
Some brands of semi-metallic pads are inherently noisier than others because of the ingredients used in the manufacture of the friction material. Think of it this way, the longer life pads or pads that claim to have more stopping power usually contain more metallic material. Yes, they will last longer and could enhance braking but the chance of causing a squeal noise is very high. The squealing noise that might be caused from use of these pads does not affect braking performance and does not indicate a brake problem.
Brake squeal is caused by vibration between the brake pads, rotors, and brake calipers. Having the brake rotors refinished or trued (machining a small layer of the metal away from the disc brake rotor to make it smooth and "true" again) and a thin layer of a silicone compound placed on the back of the brake pads are a great way to reduce the squeal if the semi-metalic pads are the culprit of the noise and not due to a worn out disc brake pad.
Why does this squeal happen anyway?
The brake rotor is the round metal object that the brake pads squeeze together like the white part of an Oreo cookie. The rotor is metal and has a smooth slick finish, and the brake pads are made of metal shavings and also have a smooth somewhat slick finish. The more metallic material found in the pad the greater the chance for noise, and vise-versa.
The other type of brake pad is called organic. There is no metallic material used in this kind of brake pad. Organic style brake pads can only be used on vehicles that are specifically designed to use them. Improper use of organic pads on a vehicle designed to use semi-metallic can severely reduce stopping ability. Organic pads are softer than semi metallic and usually do not have a squeal problem. Unfortunately due to shorter life expectancy, inability to stop larger vehicles, and the addition of substances like asbestos in their construction, they are not very widely used.
When are squeals signaling a problem?
Sometimes brake squeals are an indication that maintenance is required. Some common conditions that cause brake noise are:
*
Heat cracked or worn "un-true" rotors
*
Rough finish on resurfaced rotors
*
Loose fitting brake pads in the brake calipers
*
Lack of silicone compound on back of brake pad
*
Missing springs or anti-rattle clips that should be on the caliper or pad
*
Improper tightening sequence of lug nuts or caliper hardware
*
Contamination on the brake pad i.e. brake fluid
Most GM cars are equipped with a small thin piece of metal attached to the brake pad to act as a warning indicator when the pad material is getting low and the brake pads should be replaced. This inexpensive warning device can be deceiving though, because this warning noise is present when the brakes are not depressed. When the brakes are applied, the warning noise goes away because the indicator has now been forced against the brake rotor and is not able to vibrate which causes this whistling noise.
If you hear brake noises other than a squeal, it could mean your brake pads are worn out and need to be replaced. If your brake pedal feels different than normal or if you've noticed any change in the way your vehicle brakes (pulls to one side when braking or requires more pressure on the brake pedal), or loss of brake fluid have the brake system inspected at once.
What should I do?
What can you do as a customer to reduce the chance of squealing brakes? First of all, noisy brakes should always be inspected to make sure there isn't a problem with the braking system. If the pads have worn down to the point where metal-to-metal contact is occurring, your vehicle may not be able to stop safely, and you may damage the brake rotors or drums to the point where they have to be replaced. Sometimes a few harder-than-normal stops can "de-glaze" the brake pads and help reduce the squealing noise for a while.
There are many aftermarket brake pads that claim to be "quiet" or have been "designed" for import and front wheel drive vehicles that you can choose from. Personally, I have had the best luck replacing the disc brakes on small vehicles like Honda and Toyota with original equipment pads from the dealership rather than using aftermarket brands. It is usually more expensive to purchase these pads from the dealership, but the quality is much better. I am an independent shop owner and my whole business philosophy is to buy as little as possible from dealerships, but after trying many squealing aftermarket brake pads, I have learned my lesson and pay the extra money.
04-08-05, 08:57 PM
#11
Driver School Candidate
I recently complained of noise from my front brakes. A clicking sound when changing directions. As this appears to be normal, per several conversations with Lexus techs, the one thing they did say when replacing the front pads is to be sure and also include a Fit Kit. The part number is 0494730120 . This is recommneded when ever new OEM pads are replaced, at least on my GS430. Also, check the anti squeel shims. These may need to be replaced also, depending on condition. The Fit Kit for the front brakes, sells for about $45.00 and consists of new X springs, clips etc. that hold the pads in the caliper assemble. Mayby this is something that should be considered when ever pads are replaced. I know when mine are due, I will also include this Fit Kit. The tech seemed to know what he was talking about. 
talk about expensive 
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