I started a thread a few days ago hoping to get an idea on why the rear brakes on some of the 08 SS/TC's (Incuding my own) are wearing so fast.

I did some testing with my car by adjusting the e-brake and measuring the clamping force of the caliper after releasing the E-brake and found that Jerking the e-brake back when parking the vehicle caused the caliper to hold some residual pressure on the inboard pad after releasing it.
THIS, caused my rear pad wear issues.
(Those of you who do not know, I used to drive 100 miles a day on the highway at 65mph With NO ABUSE to the car.)

One other thing I think we should worry about is the debris that get thrown on the inboard side of the rotor ie. Dirt, Salt, Tar, or whatever other happy things we find ourselves driving through.

If GM does not have a backing plate for the rear rotors then I'm probably going to design and build some for my own peace of mind.

One last thing, I have nothing against anyone driving an SC. The TC has problems and its not the greatest car in the universe, but I still love mine.

 

My car only has 5k on it, and Ive been noticing grinding from the rear brakes. I havent pulled the wheels yet, but just by reaching through I can feel the inside of the rear rotors are very scored. My pads still have good life but the rotors are getting destroyed. Im not hard on the brakes or ebrake. Im calling my dealer now to find out about warranty work.

As far as the backing plate it can go either way....sometimes backing plates just facilitate the accumulation of debris in the brakes by trapping dirt, sand, salt etc...

 

Never seen that, I'm a technician and ive never seen rotors groove on the backside with a backing plate. But, its still possible.

 

I was saying that the inside of my rear rotors are grooved, not that the backing plate caused it. My car doesnt have backing plates either. As far as the backing plate goes, I was just saying that on some cars Ive seen a lot of sand get caught between the backing plate and caliper and rotor.

As for why my rotors are scoring even though there is still plenty of pad material left Ive yet to determine why, Im going to pull a wheel and take a look. Either way, its going in to the dealer tomorrow, cause its only got 5k mi on it so its their problem not mine. haha

 

The more I read about rear brake issues, the more I think it could be something as simple as a number of cars from the factory don't have their e-brake cables adjusted properly. All it takes is the slightest bit of residual pressue to toast those pads in a few thousand miles. Not to mention how insanely hot they'd be when you actually do use them.

 

On further investigation tonight I felt the rears of mine and there is a single groove at the same radius on each and on the outside edges there are ledges I can feel. Profile of it kinda feels like this:

 

Thats nothing out of the ordinary. Are the guys with pad wear only wearing out the inboard pad?

 

try taking the calipers off and lubing the caliper slides. Make sure you can move them back and forth freely. IF they are frozen it will cause one side to wear faster then the other...

 

Again I havent pulled a wheel yet, but the outter pads in the back have plenty of life left but Im not sure about the inner pads. I just reached my hand through the wheel and could feel the inner side of the rotor was very groved in multiple places, and Ive been getting grinding in the rear while braking. Its going to the dealer tomorrow. Even though Id probably just be better off doing it myself at my shop, I figure I mine as well take advantage of the warranty.

 

Great idea except there arent pads available..........unless you convince them to put Solstice pads on, they might not for fear of the claim getting bounced since the part theyd actually have to bill out(TC pads) doesnt exist in any warehouse right now) Youre gonna need to bitch enough to make sure the dealer remembers they can use equivalent parts in emergencies. Also note that you can be reimbursed for repairs done outside the dealer if parts arent available.

And unless youre positive that the parkbrake thing is the root cause, its just gonna reccur with fresh TC pads. I think the problem is heavily related to the aggresive compound of the TC pads

 

Well Im assuming they are gonna leave the original pads cause theyre still fine. I figure theyll just do the rotors...who knows, we'll see what they say tomorrow morning.

 

#08-05-22-004: Information on Brake Squeal/Squeak Noise - (Jul 15, 2008)

Subject: Information on Brake Squeal/Squeak Noise

Models: 2008-2009 Cobalt SS, HHR SS

Do This


Don't Do This

Inform the customer that this is a normal characteristic of the high performance brake system.


DO NOT repair or replace the rotors or brake pads.

Under certain weather or operating conditions, occasional brake squeal, squeak, or other noise may be heard with the above vehicle's performance braking system. The brake system is designed for superior fade resistance and consistent operation using high performance brake pads. Some brake noise and brake dust is considered normal and do not affect system performance.

DO NOT attempt to repair or replace any parts for this kind of noise concern. The squeal or squeak noise is not indicative of any concerns with the braking system. You may wish to give the customer a copy of this bulletin.

only bulletin on SI for brakes nothing yet on the grooving i have 800 miles on mine im going to check to see if mine have the same problem

 

Very Important thread! I was about to make a new one myself because i had to bring my car back to the dealer today one day after getting the front rotors replaced (was one of the vin's that had the first bad rotors) My car was one of the first 2008 t/c's and i only have 7900 miles and the rear brakes are screwed. Yup it's the inside of the rotor all scored up and getting a nasty scraping sound. The dealer is ordering new pads and rotors but but but if they are going to replace the parts with the exact same as original then this is going to happen again and again and again. I suggest everyone who is having this same problem contact GM to make them aware that this sure as hell is going to be an on going problem. Please refrain from attacking this idea as being useless because every single gm car i have had (all ordered btw) had horrible brake problems where the dealers didn't want to do jack ****. Even the zone rep refused to do anything and this coming from a family with 60+ years working for GM. But now the dealer is actually replacing the parts without a fight. Yes sucks this is occuring but I know it will be better to make GM aware that a lot of us are having the same problem with low miles on the rear brakes.

 

Just dropped my car at the dealer to get the rear brakes done, and while I was there low and behold.......theres a recall on the front brakes like everyone has been saying!!! I called my dealer about a month or two ago and asked about the recall and they said, we dont know anything about a recall you have to wait to get a letter from GM. I never got such a letter, but atleast now theyre recognizing the issue. So.....as long as they can get the parts theyre going to be doing the front and rear brakes today. This is a PITA.

As far as the idea to contact GM, I would be willing to, but who exactly do we contact?

 

look in your owners manual. There's a phone number for GM Customer Care in the back. You can also ask your dealership for the number...

 

I can understand that if the pads are wearing quicking in general, but it seems like the inside is wearing much faster than the outside in most cases...wouldn't this point to something other than pads?

 

Agreed, my inboard pads were at 3mm last time i checked them while the outboard pads had almost twice as much.

 

Well if thats the case, then I agree, its much more likely to be an issue with the caliper bracket/pad mounting or caliper. I hadnt seen where anyone had specifically said the pad wear was predominantly the inboard pad before now, only that the rotor scoring was inboard side.

 

The caliper piston may not be releasing fully when the e brake is released or the pad could be sticking and on front wheel drive cars rear brakes don't do much so you proubly wouldn't feel drag. When people had there brakes serviced did the dealer say they found any problems.

 

The backing plate idea is a good one, there is actually a backing plate developed for the front brake(non-TC) due to a similar issue with inboard side front rotors.

 

As I've said previously if the caliper slides are sticking or frozen this will cause the pads to wear faster on one side...

 

Ok just got my car back from the dealer....heres the skinny:

Front rotors have been ordered and will be replaced under warranty.
Rear pads have been ordered and will be replaced under warrant. Theyre having trouble getting the pads, but heres why:
The rear brakes are going because there is "an abnormally high metallic content in the pads" used on our car. This is causing the pads (for some reason only the inner pads) to wear extremely fast, and score the rotors(which is what Ive had happen to my car.)

So due to the fact that the supply of pads for our cars all most likely have a high metallic content they cant just throw new pads on. Their probably going to have to get new pads from the supplier.

So, as of now, my cars back and Im waiting to hear back from the dealer. Once they get the parts Ill be going back in.

P I T A!

 

That sound suspiciously like what Ive been saying.....


Why not just ask them to put Solstice pads on......according to your warranty if its going to take more than 10days to get parts your or the dealer is allowed to repair the car with available parts, even if not GM(or the exact part number)

 

high metallic content in the pads makes sense. BUT, if that was causing the scoring of the rotors then why isn't it happening on both sides? I'm not trying to say the dealer is wrong but something seems out of place.

almost forgot about DGAF260's question. When I had my 5k service done (at 10k miles) I was told about the Rotor recall that was out for the front brakes. Well, idk about chevy, but when i worked at lexus we checked the front and rear brakes everytime the vehicle was in for service (even 5k). So when I rotated my tires at 13k I was surprised to find the rear pads with 3mm inboard and 6mm outboard. So either the dealer didn't check my brakes or didn't see it as something to worry about.

 

Hmmm... good to know. Ill give them some time and see what happens. If it takes too long then Ill throw that idea at them.

Heres my problem. The service guy said theyre going to do rear pads, but not rotors, theyre just going to machine them. From what Ive learned as a tech from my boss is that new cars dont really have thick rotors to begin with, so machining the rotors may cause them to warp soon after because theyre so thin...but who knows. Either way, Im not too comfortable getting them machined, I know at my shop we never turn rotors any more, we always just replace them, seeing you can get new ones just as cheap as turning the old ones. So we'll see what happens, he said hes going to machine them, then measure them and if theyre still thick enough they wont replace them. Seems like an iffy idea to me.