A little advice on Disks

[silhyboy]

Hey all,

Here's my issue:
For the last couple of weeks, my rear brakes have been making grinding noises when applied. I assumed that the problem was the pads were worn out and needed replacement. So when I had the time to do so, I took the car into a dealer service center. This was Tuesday. When I left the dealer, the brakes no longer sounded metal on metal, but were now vibrating under pressure. I called the dealer along the way and found out that they ground the rotors down to take any grooves out of them. Standard practice, right?

Well, when they ground the rotors down, they actually introduced a warp in them that translated into my vibration. I asked them what they planned on doing as it would chew up the new pads much quicker than a flat rotor. They asked me to bring the car back and they would re-grind them.

Ok, so the next morning, I brought the car back and they re-ground them. This is when I was told that the machine they use was having trouble with the rotors as they were "too hard" for the bit to cut properly and that they couldn't get them perfectly flat. (????) They would order new pads and have them in a day or so. When I asked if replacing the rotors would solve the vibration issue I was told yes. So I decided to just replace them and the service center was kind enough (ahem) to eat the labor cost on them.

So... Friday rolls around and I get the car in, get new pads and rotors. Great! I head off on my merry way and have no problems for about 100 miles. The car now shakes violently when the brakes are applied at 60mph or above. It doesn't matter how hard or soft you apply them, they just vibrate worse than before. it is so bad that I am not driving that car till they can take it in and solve the issue.

Here's my question to all of you Mazda Tech heads out there:

What is the front and rear disk size for a Mazda 3s with the 2.3l engine.

I ask because when I look at the new rotor from the side, it looks to be dramatically smaller than the front. and I am wondering if the dealer just grabbed a generic Mazda rotor and adjusted the caliper assembly to fit.

Let me know your thoughts!

P.

 

[rsvinylgraphics]

the rears are much smaller than the fronts, this is the case in most cars with 4 wheel disc brakes.

 

[DarkAngel]

Well first off, sucks what you are going through. Second, there is no way they can adjust the caliper assembly to fit the rotor. The caliper bracket is preset for the proper height and can not be adjusted. There is definitely something wrong there. I would keep complaining until they figure out the problem. Front rotors are always bigger than the rears.

Do you have aftermarket wheels on your Mazda? Hubcentric ring/s was not re/installed?

 

[silhyboy]

***UPDATE***

So in looking further into this, I've found that there actually are 2 different sized rotors for the Mazda3s 2.3L. 10.1" and 11". Does anyone know what the defining characteristic as to which rotor would be on the car? (i.e. automatic vs. standard). I would likek to know, if for any reason, at least peace of mind.

I wondered about the caliper adjustment because when I had a chance to look at the assembly, the parts have no rust on them. When compared to the front assembly, these look brand new. Is it possible that when they ordered the new rotors, they ordered the 10.1" size when the car had the 11" rotor? And if so, is it possible that they also replaced the calipers just to get me out of their hair?

I know, a lot of "ifs" but as far as I can tell, that is the only thing I can come up with at the moment...

As of right now, the car is in their hands for the next week (as I am on the road) so we'll see what they do...

P.

 

[silhyboy]

Do you have aftermarket wheels on your Mazda? Hubcentric ring/s was not re/installed?

The car is completely stock. Bought direct form a Mazda Dealer in 2004 and no aftermarket parts added. Tires have been changed 2 times (car has almost 90k Miles on it) but even then, nothing other than scheduled service has been done to it.

P.