91 Grand Prix GTP brake question

[Johnnystats]

Hey all -

 

I have a 91 Grand Prix with 21K miles on it. I have noticed that after driving the car and using the brakes a bit, there sometimes is a high pitched squealing when using the brakes. Then, when resume driving again, I sometimes hear a squealing noise from the front wheels - then eventually it goes away. I had my mechanic check the brakes out and he said that they are fine - the car doesn't need brakes as the pads and rotors are fine. He said since I hardly drive the car, this could cause it and should try to drive it more. Any idea what this could be?

 

Any advice would be helpful.

 

Thanks!

[Cutlass350]

I have a 91 Grand Prix with 21K miles on it. I have noticed that after driving the car and using the brakes a bit, there sometimes is a high pitched squealing when using the brakes. Then, when resume driving again, I sometimes hear a squealing noise from the front wheels - then eventually it goes away. I had my mechanic check the brakes out and he said that they are fine - the car doesn't need brakes as the pads and rotors are fine. He said since I hardly drive the car, this could cause it and should try to drive it more. Any idea what this could be?

 

Wow, only 21K miles, nice!

 

Imho, your mechanic is not very good.

Brakes are the number one things that shops do.

Complaints about squealing are the most common. There are many reasons for squealing. The most common one is worn pads.

Then, there are a number of other common causes.

 

With 21K miles, and being ~over 20 years old, there are a number of possibilities.

Assuming the disks are fine, the pads are likely dried/cracked. Also, the calipers can stick. At ~20 years old, the pads, calipers, caliper sleeves, and pins have done a good long job. Imho, if they need to be replaced, that's fine and to be expected because of their age.

 

It's not just mileage that wears on parts. A good example is how tires are now dated.

http://www.edmunds.com/car-care/how-old-and-dangerous-are-your-tires.html

 

 

At the very least, you should have new pads/shoes put on - regardless of wear. Also, new caliper sleeves and pins.

It's a gamble if the caliper is sticking or not. I'd say there's maybe an ~30% chance that the caliper(s) is(/are) the problem. The only way to tell for 100% sure to replace them.

 

New caliper sleeves ~$10:

 

 

Good Luck!

Edited October 6, 2013 by Cutlass350

[Johnnystats]

Wow, only 21K miles, nice!

 

Imho, your mechanic is not very good.

Brakes are the number one things that shops do.

Complaints about squealing are the most common. There are many reasons for squealing. The most common one is worn pads.

Then, there are a number of other common causes.

 

With 21K miles, and being ~over 20 years old, there are a number of possibilities.

Assuming the disks are fine, the pads are likely dried/cracked. Also, the calipers can stick. At ~20 years old, the pads, calipers, caliper sleeves, and pins have done a good long job. Imho, if they need to be replaced, that's fine and to be expected because of their age.

 

It's not just mileage that wears on parts. A good example is how tires are now dated.

http://www.edmunds.com/car-care/how-old-and-dangerous-are-your-tires.html

 

 

At the very least, you should have new pads/shoes put on - regardless of wear. Also, new caliper sleeves and pins.

It's a gamble if the caliper is sticking or not. I'd say there's maybe an ~30% chance that the caliper(s) is(/are) the problem. The only way to tell for 100% sure to replace them.

 

New caliper sleeves ~$10:

 

 

Good Luck!

 

 

Hey, thanks for the detailed response. Yeah, my mechanic said the discs were fine and the pads were fine - but now I am wondering if he looked at the pads for cracks. So, I am guessing that the squealing I am hearing once I am off the brakes, that could be that the calipers are sticking. Let me ask you - am I doing any harm by driving the car like this if it what you described with the pads and sticking calipers? I will end up getting it done - but just wanted to know if I could wait until the Spring or not.

 

Thanks again for your detailed response. I appreciate it

[Cutlass350]

Hey, thanks for the detailed response. Yeah, my mechanic said the discs were fine and the pads were fine - but now I am wondering if he looked at the pads for cracks. So, I am guessing that the squealing I am hearing once I am off the brakes, that could be that the calipers are sticking. Let me ask you - am I doing any harm by driving the car like this if it what you described with the pads and sticking calipers? I will end up getting it done - but just wanted to know if I could wait until the Spring or not.

 

Thanks again for your detailed response. I appreciate it

 

You will not "hurt anything".

But, if the pads are cracked (likely), then they also can have a slight glaze. All either of that means is that you'll have ~~90% of your braking power - so the car will take longer to stop in an emergency stop situation. So, in general, you're fine. Just don't go driving fast and crazy.

 

 

Cracked/glazed pads are common. The cheap Autozone pads will often glaze and crack after a few very hard stops.

 

In the following video, he's replacing pads with cracks: You can kinda see the cracks in the pads (it's not a great HD clear video, but you see enough )

How To Replace Brakes & Rotors on a Grand Prix GTP

Start at ~1:50

 

 

Pad squealing can also be cause the pad alignment method is "loose" and therefore engagement and disengagement of the pads happens at an angle. The pads will then have a slight angle, which makes a noise. I'm not sure the alignment method on the pads on your car. Some cars, especially older ones like yours may have the option to use grease/glue/whatever to keep the pads flat/quiet against the caliper piston.

 

Some older cars always have some front brake squeal. Part of that is due to the newer pad material - no more cancer causing asbestos. And, part of that is due to the worn alignment channels that happens in the caliper/bracket.

 

 

If the car gets new pads and calipers, and the rotors does not have any grooves or cracks, and it still has some brake squeal, then, the only way to get rid of a brake squeal is to try different brake pads. Not the most high tech way of doing it, but it often helps. Of course, it makes more sense if a person is doing the brake work. Still even then, they can end up paying $50-$200 trying out different brake pads. I don't know the options and brake brands for your car.

 

BTW, it takes miles and stops for any new pads or shoes to wear-in. So, there could be some noise and some light smell for the first ~20-50 miles.

 

For sports cars, Camero, Mustang, etc, there are many different pad options. Some pads a lot of noise, some make a lot of dust, some last a long time, some last for ~30K miles, some are for track only use (they need to be hot to fully work), etc. My pads make a ton of dust and wear very quickly. But, they are the best for a street/track application. And, they can be used in the winter, when the temps get below 0F. Although, my car mainly sits in the garage during the winter. During nice days with clean roads, I may take it out. I hate seeing my car sitting for 4+ months.

 

Good Luck!

[Johnnystats]

You will not "hurt anything".

But, if the pads are cracked (likely), then they also can have a slight glaze. All either of that means is that you'll have ~~90% of your braking power - so the car will take longer to stop in an emergency stop situation. So, in general, you're fine. Just don't go driving fast and crazy.

 

 

Cracked/glazed pads are common. The cheap Autozone pads will often glaze and crack after a few very hard stops.

 

In the following video, he's replacing pads with cracks: You can kinda see the cracks in the pads (it's not a great HD clear video, but you see enough )

How To Replace Brakes & Rotors on a Grand Prix GTP

Start at ~1:50

 

 

Pad squealing can also be cause the pad alignment method is "loose" and therefore engagement and disengagement of the pads happens at an angle. The pads will then have a slight angle, which makes a noise. I'm not sure the alignment method on the pads on your car. Some cars, especially older ones like yours may have the option to use grease/glue/whatever to keep the pads flat/quiet against the caliper piston.

 

Some older cars always have some front brake squeal. Part of that is due to the newer pad material - no more cancer causing asbestos. And, part of that is due to the worn alignment channels that happens in the caliper/bracket.

 

 

If the car gets new pads and calipers, and the rotors does not have any grooves or cracks, and it still has some brake squeal, then, the only way to get rid of a brake squeal is to try different brake pads. Not the most high tech way of doing it, but it often helps. Of course, it makes more sense if a person is doing the brake work. Still even then, they can end up paying $50-$200 trying out different brake pads. I don't know the options and brake brands for your car.

 

BTW, it takes miles and stops for any new pads or shoes to wear-in. So, there could be some noise and some light smell for the first ~20-50 miles.

 

For sports cars, Camero, Mustang, etc, there are many different pad options. Some pads a lot of noise, some make a lot of dust, some last a long time, some last for ~30K miles, some are for track only use (they need to be hot to fully work), etc. My pads make a ton of dust and wear very quickly. But, they are the best for a street/track application. And, they can be used in the winter, when the temps get below 0F. Although, my car mainly sits in the garage during the winter. During nice days with clean roads, I may take it out. I hate seeing my car sitting for 4+ months.

 

Good Luck!

 

Again, thanks for this great information. I'm not too worried about the squealing when I brake - but was wondering what the squealing was once I let off the brake. I remember reading somewhere about frozen calipers. I guess that is what you are mentioning above. At least I know what to ask/tell them when I bring my car in. Being mechanically inclined would help - which I am not Again thanks for the great info!

[55trucker]

Semi-Metallic/Carbon-Metallic pads are notorious for squealing when little to no pressure is applied to the brake pedal, when you apply the brakes the squeal stops because of the pressure applied. It's quite possible that these are the pads you have in use as they were the defacto pad installed 20+ years ago.

[Schurkey]

How about starting with inspecting the anti-rattle clips 'n' shims, and verifying that the fasteners are appropriately torqued?

 

The typical causes of brake squealing when no pedal pressure is applied are 1) worn linings activating the audible wear sensor reed; and 2) pads loose in the caliper.