What causes brake pads to glaze over?

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My 08 Malibu with 21K on it developed squeaky brakes a month ago. Took it into the dealership and they said there was a TSB for squeaking brakes... apparently the pads glazed over and they had to "de-glaze" them and clean the rotors.

It has been fine for the last 20K miles, and I've owned the car since brand new with 50 miles. Proper break-in procedures were followed per the owners manual according to brakes and engine speeds.

What causes pads to glaze over? Anything I can do to prevent it again?
 
I don't know if was caused by "glazed" brake pads, but I've fixed squeaky brakes on two cars by repeated application of the brake pedal from 55MPH till about 10MPH. (You need a road with light traffic to do this). Get the brakes good and hot (you'll start smelling them), then drive at 55MPH for several minutes to cool them down.
 
Welcome to GM factory brakes. Get used to it until you buy aftermarket pads/rotors.

We're dealing with the same thing on our 07 Impala and have dealt with the same thing on all previous GM products.

Pad glazing from excessive heat and warped rotors.

They'll cut the pads and rotors under warranty - forget trying to cut/resurface the rotors again - they'll be too thin and heat will be an even bigger problem.

As soon as aftermarket parts get thrown on, they'll go 50,000 + miles without problems.

That's what I've experienced.
 
I think glazing is caused by very light braking application over many miles. Riding the brake pedal very lightly for long distances might be one example.
 
I have had the opposite experience with GM brakes over the years. Current 2003 Saturn 63,000 miles and still has original brake pads and rotors at all four positions. Chevy truck had original front pads for almost 70,000 miles at which point I replaced rotors and pads with NAPA parts. Rear drum brakes were still original after almost 11 years and 110,000 miles.
 
The brakes on my truck glazed over badly. I didn't drive it very often and rust would build up on the rotors between uses. Eventually, the pads and the rotors glazed.

I bought new pads (with a coating to help bed them in) and went to replace them. I was very surprised to see the installed pads still had a great deal of use left even at 80k miles. I wanted to unglaze everything and reuse but since I had to go to all that work to open everything up, and had already purchased new pads, I went ahead and replaced.

All four corners are still working well, even though I still maintain the same usage habits. It could be that there aren't enough miles on the new pads yet, or they have a more glaze-resistant compound. Dunno.
 
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My impression is that the brakes continually get hot enough to develop a glaze, but not hot enough to simultaneously burn it off. If the brake compound and the size of the system are matched to the mass of the vehicle, this shouldn't happen.

My grand prix does this, I fix it by doing a couple of hard stops like brianl suggests. I try to do it more from 70 to 40 until I start to feel a little bit of fade. After letting them cool off, the car stops great.
 
All pads and shoes 'glaze'.
Unless they are brand new, this is how all used brake material looks.
Sanding them will always get rid of noise for a short while - maybe longer if there was foreign material on them.

The future? Keep the calipers and shoes lubed at any points of movement. Use the best pads that you can get your hands on.
 
Originally Posted By: Drew99GT
Welcome to GM factory brakes. Get used to it until you buy aftermarket pads/rotors.

We're dealing with the same thing on our 07 Impala and have dealt with the same thing on all previous GM products.

Pad glazing from excessive heat and warped rotors.

They'll cut the pads and rotors under warranty - forget trying to cut/resurface the rotors again - they'll be too thin and heat will be an even bigger problem.

As soon as aftermarket parts get thrown on, they'll go 50,000 + miles without problems.

That's what I've experienced.




You aren't kidding, on my Impala I had to change the rotors every 5-7k(and pads) because they would glaze & warp. After warranty I went aftermarket, bought slotted/cross drilled rotors and Bendix brake pads. After that I never really had problems, maybe every 25k i'd get the pads checked out and they were warrantied for the lifetime of the vehicle so I would get em changed out at every inspection for free =)

GM Rotors are horrible, many issues with them across several cars and is a widely or was a widely known problem.
 
I get all alone on a highway or an off ramp and jab the pedal several times. Deglazes brakes and is fun too. Light and slow brake application is the cause.
 
Originally Posted By: mechtech2
The future? Keep the calipers and shoes lubed at any points of movement. Use the best pads that you can get your hands on.



Just watch out where you put the grease. It attracts a ton of dirt and makes your caliper look nasty. Strangely, despite all of the aftermarket propaganda to lube the caliper clips, shims, etc, all of the factory brakes that I've seen do not use any lube on the shims or the clips.
 
Had the pads on my truck glaze best solution I found was to pull them out and rub them back and forth on the concrete driveway till they are rough then throw them back on, works everytime.
 
Swalve - Well then what are we talking about? I don't know what a glazed pad is. I've done countless brake jobs.
Pads get shiny, as do rotors, as they seat together.
Unless there is a foreign material on them, like a leaky wheel cylinder that gets brake fluid on shoes, I think that amateurs are making up terms.
 
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