Squealing brakes

A little squeal will often happen after washing, if water gets in and forms rust. That should be very temporary. A persistent, increasing squeal is going to require a look inside, and waiting to get that done *might* damage the brake drum enough to require its replacement.

 

The way id look at it is "its a new car with warranty and the dealership is going to fix it for free" go to the shop and have them look. can't hurt and might save u some time/money down the road. Also incase you don't know most dealerships/car makers have a 12K mile warr on brake problems like pads wearing our or making noise. it can be difficult to get them to deal with your brake concerns after that mile cutoff so go get a history going on it now . It might save you hassle in the future

 

Hello,
I have had squealing brakes for several months, and found that cleaning them using the friction brake technique only solves the problem for a very short time.
Like another newsgroup member, I'm not completely convinced it is corrosion.
On my car, the problem starts after travelling for a while, after the discs have warmed up I guess, never when starting after the car has been resting.
It happens in the dry.
It starts when I apply the brakes, as if a spring mechanism does not return the brakes into the same place, and they start to rub against the disc. Squealing can occur at low speed or high speed, but is generally much worse if crawling along in traffic. It can occur on motorways at high speed.
I contacted Toyota, complaining that the problem was a design issue, since the discs had become noisy because of lack of wear, rather than over-use, but they refused to meet the £500 cost of replacing discs (the garage solution), to solve the problem. Surely replacing the discs will result in the same problem when they begin to rust!
My squealing is so loud at low speed that passers by will turn around and look, and it is almost deafening to have the window open, hence my letter to Toyota.
Now, I am going to highlight the issue and make sure that others are made aware. Get the issue looked at whilst in warranty.
Anyone get an alternative ideas about the cause, and how to solve it please?
Regards.

 

Usually, when disk brakes make noise, this is due to either the disk, or the brake pads vibrating.

In the former case, if the disk is not perfectly true (due to wear or the accumulation of corrosion) then it will be the culprit. That is why you received the recommendation to replace the disks. You raised a good point that there's no assurance that the problem won't repeat.

In the latter case, if the pads are not worn out, it is possible to apply some silicone compound to the back of the pads to dampen the vibration.

Have you determined which wheel is making the noise?

 

Hello Patrick,

Thanks for the quick reply.

It is the drivers side front wheel which is particularly bad, and the passenger side front to some extent.

Another observation is after long journeys, there is a build up of black dust on the wheel covers, which only seems to be there on the front wheels. I don't remember seeing this in the past.

Is the dust what you would expect from the a not perfectly true disc or vibrating pads.

Does is seem more likely that it is the disc, rather than vibration, as the noise can occur over a wide range of speeds?

Many thanks and regards,

 

More...

I have found the following on another newsgroup and wonder if any can comment further please, as this is pretty much exactly my experience:

have just brought my mark 2 back from it's 30000 mile service. I have a nasty squeak at low speeds coming from the rear drivers side wheel. I asked them to look at this and they have come back and said I need new disks as the old ones are scored and corroded. A nice cost of £303 because you can only buy them in pairs apparently.

Now how can that happen within 30000 miles on a car that hardly uses it's brakes. This is the first time I have ever had this problem on any of my cars. Also why does my wheel squeak only when moving and not braking. I have a feeling a calliper is getting partially stuck and the pad is still slightly rubbing the wheel. On both occasions I have asked them to look at this problem they have not even taken the wheel off.

 

Your analysis sounds correct. Stuck calipers can squeak when not braking as the pad gently slides across the surface of the rotor. When you brake, the increased pressure stops the vibration, eliminating the squeal or squeak.

You ask how brakes can fail when used so little. It is often harder on mechanical devices to not be used: seals dry out and stick, surfaces rust, and lubricants cake. Regular use of friction brakes wears out the braking surfaces, but keeps the surfaces clean and all of the moving parts running smoothly. With the Prius, the pads and rotors don't wear out, but they tend to rust and stick.

Have you tried cleaning your brakes using the N braking technique? Sometimes this is enough to get things working normally again.

Tom

 

I suggest that you shoot a healthy stream of water into the front wheels, to clean off the brake pad dust. Then immediately take the car for a drive (so that the water doesn't have a chance to rust the rotors further), get up to 40-50 mph, then shift to N and moderately brake to a stop. Repeat several times. See if that helps.

Looks like the OP did so and obtained temporary relief, given his first post cited above. It seems that the disc is the problem, not vibrating brake pads.