My theory on the rear brake issue.
06-12-2010, 10:10 PM
#1
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My theory on the rear brake issue.
There are seemingly three separate issues when it comes to the rear brakes on the Cobalt SS.
1. Deep grooving of rotor. Many have seen this uneven wear on the face of the rotor. This issue has everything to do with the OEM rear pads. Many members have switched pad types and have seen this issue disappear. The OEM rear pads also contribute to the next problem, as you will see. Here is a pic of the grooving, but it didn't come out so well. Sorry about that.
2. Excessive wear of inner rear brake pad on either passenger side, driver's side, or both. This usually leads to excessive wear of the inner rotor face as well. This issue is cause by the design of the caliper slide pins. See pic below. Some members believe that the pins were not greased from the factory, but I believe the grease just seeps out because there is not enclosed environment provided for the slide pins via an accordion-style rubber boot, as you see on most caliper brands. Notice how dirty the slide pin is with the combination of grease and brake dust. The brake dust mixes with the grease, making it sticky. The caliper heats up and the grease seeps out. After a certain number of miles or hard braking, you probably have dry/dirty slide pins again. The OEM pads contribute to this issue with the amount and type of material that sheds off the brake pads. If you take one of your rear wheels and one of your front wheels off and clean them, you will notice that the brake dust on the inside of the rear wheels is much more sticky and gummy. You will also see evidence of this on your calipers. Solution to excessive wear of inner rear brake pad: change pad type and be sure to clean/grease slide pins every 5K miles or so. The pin in the pic has about 2K miles on it since last clean.
Rear caliper:
3. The other issue is the phantom emergency brake. Does your emergency brake not work for ****, then suddenly start working out of the blue? Then clean and grease the caliper slide pins. Voila!
1. Deep grooving of rotor. Many have seen this uneven wear on the face of the rotor. This issue has everything to do with the OEM rear pads. Many members have switched pad types and have seen this issue disappear. The OEM rear pads also contribute to the next problem, as you will see. Here is a pic of the grooving, but it didn't come out so well. Sorry about that.
2. Excessive wear of inner rear brake pad on either passenger side, driver's side, or both. This usually leads to excessive wear of the inner rotor face as well. This issue is cause by the design of the caliper slide pins. See pic below. Some members believe that the pins were not greased from the factory, but I believe the grease just seeps out because there is not enclosed environment provided for the slide pins via an accordion-style rubber boot, as you see on most caliper brands. Notice how dirty the slide pin is with the combination of grease and brake dust. The brake dust mixes with the grease, making it sticky. The caliper heats up and the grease seeps out. After a certain number of miles or hard braking, you probably have dry/dirty slide pins again. The OEM pads contribute to this issue with the amount and type of material that sheds off the brake pads. If you take one of your rear wheels and one of your front wheels off and clean them, you will notice that the brake dust on the inside of the rear wheels is much more sticky and gummy. You will also see evidence of this on your calipers. Solution to excessive wear of inner rear brake pad: change pad type and be sure to clean/grease slide pins every 5K miles or so. The pin in the pic has about 2K miles on it since last clean.
Rear caliper:
3. The other issue is the phantom emergency brake. Does your emergency brake not work for ****, then suddenly start working out of the blue? Then clean and grease the caliper slide pins. Voila!
06-12-2010, 10:27 PM
#3
Senior Member
Thread Starter
06-12-2010, 10:30 PM
#4
06-12-2010, 11:11 PM
#7
Good info for those that are experiencing this issue.
Just FYI the calipers are actually made by ATE, not GM, as some people have said. My syster's Mazda 3 uses a slightly different version of the same caliper design. I don't know why they allow the slide pins to be exposed like that, it really doesn't make sense.
As for caliper slide pin lubricant, some people don't understand that you can only use certain products. Products like wheel bearing grease and WD40 are NOT ACCEPTABLE and will cause failure of the slide pin sealing boots as well as cause the slide pins to lock up.
Here is the only thing that you should be using in your caliper pins:
Its not going to kill anyone.
If you're dumb enough to drive around with a horrible grinding sound coming from your rear brakes because your pads are worn to the backing plates, then its your own funeral.
Just FYI the calipers are actually made by ATE, not GM, as some people have said. My syster's Mazda 3 uses a slightly different version of the same caliper design. I don't know why they allow the slide pins to be exposed like that, it really doesn't make sense.
As for caliper slide pin lubricant, some people don't understand that you can only use certain products. Products like wheel bearing grease and WD40 are NOT ACCEPTABLE and will cause failure of the slide pin sealing boots as well as cause the slide pins to lock up.
Here is the only thing that you should be using in your caliper pins:
Its not going to kill anyone.
If you're dumb enough to drive around with a horrible grinding sound coming from your rear brakes because your pads are worn to the backing plates, then its your own funeral.
Last edited by 08SSTCRD; 06-12-2010 at 11:11 PM. Reason: Automerged Doublepost
06-13-2010, 12:12 AM
#8
I changed my brakes yesterday, and noticed the same thing. I knew everyone had said the slidepins being dry caused the problem, but I didn't realize it was exposed to the elements until yesterday. Looks like I'll have to be keeping a close eye on them and lubing them often. At least they're easy to get to and remove/grease.
06-13-2010, 08:41 PM
#9
Senior Member
+1
First, lube your slide pins because GM doesn't do it from the factory.
Second, get rid of the stock pads.
Third, adjust your e-brake/parking brake so it doesn't drag when disengaged.
The rotors are fine, you don't need to "upgrade" the rotors.
My HPS rear pads/stock rotors look fine after 1500+ miles. The factory crosshatching marks are still present on the stock rotors. The front Brembos are another story - the stock Ferodo pads are slightly grooving the rotors. I wish Hawk released the HPS front pad info when I first bought the SS so I could use those instead.
First, lube your slide pins because GM doesn't do it from the factory.
Second, get rid of the stock pads.
Third, adjust your e-brake/parking brake so it doesn't drag when disengaged.
The rotors are fine, you don't need to "upgrade" the rotors.
My HPS rear pads/stock rotors look fine after 1500+ miles. The factory crosshatching marks are still present on the stock rotors. The front Brembos are another story - the stock Ferodo pads are slightly grooving the rotors. I wish Hawk released the HPS front pad info when I first bought the SS so I could use those instead.
06-14-2010, 07:40 PM
#12
Senior Member
The stock Ferodo pads don't impress me very much. They chew up rotors and leave lots of black dust. The stopping distance for the SS/TC is on-par with a Mazdaspeed3 that weighs more and has a single piston front caliper setup.
06-14-2010, 07:44 PM
#13
06-14-2010, 10:58 PM
#15
If you look at the '10 Camaro, its the same scenerio. In 60-0MPH braking, the V6 version with single piston calipers stops just as quickly as the SS with 4 piston Brembos at all 4 wheels. Once again, both systems have enough power to kick in the ABS and therefore are limited by tires.
The differences become apparent when you factor in better tires, higher speeds, and repeated braking which induces heat. Thats when the 4 piston aluminum Brembos really shine, and the cast iron single pistons on the Mazdaspeed become severely inadequate.
06-15-2010, 01:03 AM
#16
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Wanna know my theory on our brake issue my friends.. GM FORGOT TO PUT DUAL PISTON REAR BREMBO'S ON.. instead they cheap out and give us these problematic rear brake system an not only that but it looks out of place from the front brembo's
06-15-2010, 02:27 AM
#17
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My slide pins were not factory lubed. My brakes were absolutely trashed front to rear when I changed EVERYTHING at a little ove 20K I think. Yes I use the permatex ceramic brake lube, as if there is another acceptable choice in the matter. HPS pads were what I replaced the rears with, they crumbled and came apart on the track (yes they were bedded prior to the event). I will not endorse the use of those pads competitively. I bought factory front pads because frankly they were in decent condition albeit with some of fracturing of the material. Also good to mention slag on the inside of the caliper mount bracket, mine would squeel when it made contact, very annoying.
I've beat the factory brakes to death, they worked fine, were comparable in performance to Porsche, Audi and Corvettes at track days, talk bad if you want to but I can live with scored rotors if they will still work after heating up to a dull glow.
I've beat the factory brakes to death, they worked fine, were comparable in performance to Porsche, Audi and Corvettes at track days, talk bad if you want to but I can live with scored rotors if they will still work after heating up to a dull glow.
06-15-2010, 04:39 AM
#18
Senior Member
HPS pads aren't designed for race use. Hawk/Wellman does make racing pads, as well as brake pads for insurgent killing machines that beat their brake pads more severely than any race car.
06-15-2010, 09:37 PM
#19
My slide pins were not factory lubed. My brakes were absolutely trashed front to rear when I changed EVERYTHING at a little ove 20K I think. Yes I use the permatex ceramic brake lube, as if there is another acceptable choice in the matter. HPS pads were what I replaced the rears with, they crumbled and came apart on the track (yes they were bedded prior to the event). I will not endorse the use of those pads competitively. I bought factory front pads because frankly they were in decent condition albeit with some of fracturing of the material. Also good to mention slag on the inside of the caliper mount bracket, mine would squeel when it made contact, very annoying.
I've beat the factory brakes to death, they worked fine, were comparable in performance to Porsche, Audi and Corvettes at track days, talk bad if you want to but I can live with scored rotors if they will still work after heating up to a dull glow.
I've beat the factory brakes to death, they worked fine, were comparable in performance to Porsche, Audi and Corvettes at track days, talk bad if you want to but I can live with scored rotors if they will still work after heating up to a dull glow.
And as for slide pins, I'm assuming you're only referring to the rear, as the front brakes are fixed calipers and do not have any slide pins.
06-16-2010, 09:03 AM
#20
Senior Member
Thread Starter
How did you trash the front brakes in 20K miles?? You must beat the **** out of your car. I've got 47K on my front pads and they still have plenty of life left.
And as for slide pins, I'm assuming you're only referring to the rear, as the front brakes are fixed calipers and do not have any slide pins.
And as for slide pins, I'm assuming you're only referring to the rear, as the front brakes are fixed calipers and do not have any slide pins.
06-16-2010, 07:28 PM
#21
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I know I washed my car the other day and moved it back to its spot in the driveway and the next morning when I released the e-brake the car just sat there, I put it in reverse and it popped really loud when it moved then made a grinding noise while I backed up. I am planning on getting rid of the rear pads soon.
06-25-2010, 12:44 AM
#22
I know I washed my car the other day and moved it back to its spot in the driveway and the next morning when I released the e-brake the car just sat there, I put it in reverse and it popped really loud when it moved then made a grinding noise while I backed up. I am planning on getting rid of the rear pads soon.
Its because you're getting the pads wet while the parking brake is engaged, and they stick to the rotor upon release. Not a big deal. The grinding noise is surface rust on the rotor that will disappear after you drive the car.
06-25-2010, 09:30 PM
#24
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I just changed my brakes and rotors today because of the problems with the rears on these cars. No fun cuz no parts place around had the rotors so those had to be ordered then found out my 2009 uses pads from 2010 on the rear so had to hunt those down, luckily found a place that had them in stock.
06-26-2010, 12:39 AM
#25
I just changed my brakes and rotors today because of the problems with the rears on these cars. No fun cuz no parts place around had the rotors so those had to be ordered then found out my 2009 uses pads from 2010 on the rear so had to hunt those down, luckily found a place that had them in stock.