How do I determine proper brake disc size?

[markswan]

Hi all,

I want to replace my front brakes on my 2005 9-3 sport sedan. The specs I find on Alldata.com show three "levels". I cannot find anywhere that shows which ones are correct or recommended. Any help in proper ID without first taking them off and measuring would be great.

Thanks!
Mark

[Ferms_93_2.8T]

Honestly, if you want to be absolutely sure, you might as well remove the wheel and measure. I can't think of a more definitive way to assess exactly which rotors you have.

I suppose you could measure with the wheel on but I'm not sure that would be completely accurate. Do the '05's have the brake codes on the door placard?

As you've probably seen through searching the threads, there is no other absolute way. Many cars were shipped with the incorrect brake sizes for the trim level anyway.

Good Luck!!!!

[LAN]

Contact the store that you're buying the upgrades from, such as GenuineSaab and then get back to us

[Pokerguy]

Originally Posted by Ferms_93_2.8T

Do the '05's have the brake codes on the door placard?

Absolutely they should.

The sticker is found on the sill of the drivers door. Open the door and look down below the door latch on the frame or body of the car.

The following info comes from a couple of different older posts (Ferms_93_2.8T, jrldrony) ;

The sticker looks like this :



As far as the letters go (bottom line, far right) :

The first couple describes the front brake disc.

AA: 15" 285mm
AB: 16" 302mm
AC: 16"+ 314mm (mounted on 2.8 V6)
AD: 17" 345mm (starting from 2008 only on Turbo X)

The second couple describes the rear discs

BA: 15" 278mm (from 2003 to 2007 on 1.8i, 2.0t, 1,9JTD. From 2008 on only mounted on 1.8i)
BB: 16" 292mm
BC: 16" 292mm only on XWD

The third couple describes front brake caliper

CA: 15"
CB: 16"
CC: 16"+
CD: 17"

The fourth couple describes rear brake caliper

DA: 15"
DB: 16"

[SpoolinUpBlue]

^^very good info!

[markswan]

Great info indeed! Thanks very much for all of the replies.

Mark

[Bajan93]

I just check for my brake codes and my sticker is blank how is this possible, ther is no way i can tell with out measuring.

mine reads like this 13-11-1- -17-11- - - WTF!!!!

[JonV]

What Trim Level Model do you have? The Simple way is to use a manufacturers or tire racks application guide and just enter the model. You say 93SS, but is it a Linear, Arc or Aero?

[Bajan93]

sorry bout that I have a linear.

[cavedudejeff]

Don't listen to guys who tell you that you have a certain setup of brakes on a 05 Linear...

Quite a few Linears rolled off the assembly line back in 05 with Aero spec brakes front and rear. Combine that with the fact that some V6 aeros 06+ got what used to be linear non-vented brakes in the rear and finding what brakes you have can be a pain in the butt.

Like one poster on here already said... Jack up the car, pop the wheel off, and whip out a ruler. For the rears its a little easier I believe because prior to the 06's the rears could only come with 285mm solid rotors or 292mm vented rotors... so for that all you had to do is look to see if your rotors are vented.

If you are not comfortable with taking the wheel off I suggest you just go to a dealer and just sit back and get plowed.

[Ferms_93_2.8T]

Originally Posted by cavedudejeff

Don't listen to guys who tell you that you have a certain setup of brakes on a 05 Linear...

Quite a few Linears rolled off the assembly line back in 05 with Aero spec brakes front and rear. Combine that with the fact that some V6 aeros 06+ got what used to be linear non-vented brakes in the rear and finding what brakes you have can be a pain in the butt.

Like one poster on here already said... Jack up the car, pop the wheel off, and whip out a ruler. For the rears its a little easier I believe because prior to the 06's the rears could only come with 285mm solid rotors or 292mm vented rotors... so for that all you had to do is look to see if your rotors are vented.

If you are not comfortable with taking the wheel off I suggest you just go to a dealer and just sit back and get plowed.

+1, I know it sucks, but just take one front wheel off and measure. You will be much happier knowing for sure.

[jlrdrony]

Originally Posted by cavedudejeff

Don't listen to guys who tell you that you have a certain setup of brakes on a 05 Linear...

you are right
I must learn about experience advises; once, I bought pads for my Opel Omega in the dealer, I took off the wheel & pads and didn´t match. double job and go back to the dealer again. my calipers it was from Lucas and the pads I bought from Bosch.
- two different calipers for the same car and model year.

[Deli-Llama]

The size of the brake rotor is stamped into the brake caliper. You might even be able to read the numbers without taking off the wheel.

[bryubpharm]

lucky me then with an early '06 Aero I got the smaller brakes and did double check the fronts they are 302MM

AB-BA CB-DA

[maj28]

Originally Posted by Bajan93

I just check for my brake codes and my sticker is blank how is this possible, ther is no way i can tell with out measuring.

mine reads like this 13-11-1- -17-11- - - WTF!!!!

My '04 says the same thing, - - -. Sigh.

-jason

[flip5150]

Originally Posted by bryubpharm

lucky me then with an early '06 Aero I got the smaller brakes and did double check the fronts they are 302MM

AB-BA CB-DA

I have the same codes on mine but the code says that the 302mm is for a 16" rim??? I definitely have 17" stock rims so does your car have 17" rims too?

[>vw]

Measuring what you already have might not always work--the ones I already had were too small. Use the codes provided above (thanks!) or CALL the stealership.