rear brakes fail before front?

PittsburghJoe · Fri May 16, 2014 9:11 pm

Hi All,

I'm curious as to why my rear brakes failed before the fronts. I'm just a shade tree mechanic but it seems atypical to me. I have just shy of 40k on my 2012 SLS and I heard a metal to metal rubbing noise on the rear driver side and upon inspection sure enough the brakes and rotors on that side are toast. The passenger side is not as bad but getting thin. Front brakes are starting to thin but I would estimate I can get another 10k on them. Any thoughts?

Thanks,

Joe

Fri May 16, 2014 9:28 pm

Not an expert on this field but I believe brake bias and also the brake pad and rotor size from front vs. rear are factors.
The front brakes typically do most of the work, but if the car has stronger rear brake bias than other cars, the rears work more and wear out faster.
It can also be because the front pads are larger and thicker. This would more evenly spread the braking surface so they last longer.
Lastly, from what I see sold online, the front and rear brake pads are actually different products and not the same pad. They are apparently different grades of brake pads. The fronts are probably made of better materials that last longer.

As I stated, I'm no expert and I haven't had to service the brakes on my Kizashi yet but these are my guesses.

Fri May 16, 2014 9:37 pm

Kuro nailed it. Brake bias and different pad compound pretty much covers it. It happens on other vehicles too

WESHOOT2 · Fri May 16, 2014 9:41 pm

I HAD TO replace my rears at 83K; I DECIDED to replace my fronts at 90something.

And I just checked the pads today; fronts nearly gone, rears look like they'll last forever.

I'm running StopTech slotted rotors and their mating metallic pads.

paininthenuts · Fri May 16, 2014 10:02 pm

WESHOOT2 wrote:I HAD TO replace my rears at 83K; I DECIDED to replace my fronts at 90something.

And I just checked the pads today; fronts nearly gone, rears look like they'll last forever.

I'm running StopTech slotted rotors and their mating metallic pads.

I wonder what their children will look like ?

~tc~ · Sat May 17, 2014 4:35 am

Do you use the e-brake a lot?

PittsburghJoe · Sat May 17, 2014 2:04 pm

~tc~ wrote:Do you use the e-brake a lot?

almost never but how would that effect the pads/rotors? I'm certainly not an expert. Just curious.

~tc~ · Sat May 17, 2014 3:12 pm

On most cars, the e-brake adjusts the pad clearance on the rear brakes. Using it a lot can result in them being adjusted a bit too tight and premature wear on the rear brakes.

PittsburghJoe · Sat May 17, 2014 5:44 pm

~tc~ wrote:On most cars, the e-brake adjusts the pad clearance on the rear brakes. Using it a lot can result in them being adjusted a bit too tight and premature wear on the rear brakes.

I see that now that I have the brakes apart. Now the problem is that I can't get the piston pushed in far enough to get clearance for the new pads. Any ideas? I'm using a large C clamp and it will only go so far!

PittsburghJoe · Sat May 17, 2014 5:53 pm

PittsburghJoe wrote:
~tc~ wrote:On most cars, the e-brake adjusts the pad clearance on the rear brakes. Using it a lot can result in them being adjusted a bit too tight and premature wear on the rear brakes.
I see that now that I have the brakes apart. Now the problem is that I can't get the piston pushed in far enough to get clearance for the new pads. Any ideas? I'm using a large C clamp and it will only go so far!

Ok, so if anyone is out there, I see on page 324 of the service manual what my problem is. It is indeed the ebrake situation. Step 1 says remove the console panel and has a little pointer finger indicating that I should be able to click it and learn how to properly do that but it doesn't seem clickable. Any ideas?