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S197 Mustang 13.8" GT500 Rear Brake Upgrade Kit [A9-2035]


Ford spent some engineering time and money to upgrade the rear brakes on the 2013-14 Mustang Shelby GT500, going from 11.8" rotors to 13.8" rotors, and we made this kit to give you what you need to do the same. We picked up all of the GT500 rear brake parts and started studying the differences. Ford says the caliper is different, but when you actually buy one of them and compare it to the 2011-14 Mustang GT rear calipers, it is identical!

The earlier 2005-2010 GT rear calipers can be different - so we offer the calipers as an option below. Likewise the rear brake line is also a carry over from the GT, so there's no reason to upgrade that - unless you want to upgrade to proper length, stainless steel braided rear brake flex lines.

Installation of this kit is fairly painless, but you do have to pull the rear axles out of the housing to install the new caliper brackets. If you have a 2011-14 GT, just move the calipers up to their new mounting location, slap on the new 13.8" rotors we include, and you are good to go. You can re-use your old brake pads, the Centric street pad option, of course, or pick up some of our optional G-LOC track pads below.


Key Features:

  • The GT500's 13.8" rear discs are 2" larger than the base 11.8" Mustang brakes. Larger diameter provides more braking torque
  • 1-piece rotors are cost effective to replace and provide much longer wear than the smaller units
  • Re-use the '11-14 GT/Boss302 rear caliper or pick the optional calipers for your 2005-2010 GT, if you think they might not fit (and some might, you will need to test fit them over the rotor)
  • GT500's 13.8" rotor is 16.06 pounds vs 13.40 pounds for the smaller 11.8" rotor
  • Better than stock choices for the brake lines and brake pads
  • There is no dust shield on the GT500 rotor and the original one cannot be used

Parts Included:

  • Two OEM-style rear GT500 13.8" rotors
  • GT500 rear caliper brackets, left and right
  • Four rear caliper-to-bracket bolts
  • A set of new Centric Premium Ceramic rear brake pads (to go with the new rear rotors)
  • Optional G-LOC pads available in place of the Centric pads


Choose your options

Choose the appropriate options from the drop down menus below. These options will affect the final price as shown. We offer these options so that you can get exactly the brake upgrade you need, instead of a generic "one size fits all" brake kit.

Left and Right Rear GT500 Brake Calipers : If you have a 2005-2010 Mustang GT, your rear calipers might work with the GT500 rear rotor upgrade. The casting numbers might even match. But... there was a running change in machining to the casting of the caliper that could cause rubbing on the 2" larger rotor, even when spaced up with the GT500 brackets. To rule out this risk we offer new GT500 rear calipers as an option. We have found that 2011-14 GT rear calipers are identical to the GT500 calipers and do not need to be replaced. The '11-14 calipers and hoses can just be bolted to the new brackets and work.

Brake Pad Brand/Compound : The Mustang GT500 Rear Brake Upgrade Kit comes standard with Centric Premium Ceramic street pads, even if you don't get the optional replacements GT500 calipers. Why? Because we're providing new brake rotors, and rotors and pads should be changed together. Keeps from having rotor wear patterns from your old discs being transferred to the new discs.

However, we also offer the full line of G-LOC rear brake pads as an option in the drop down below, for the more performance oriented buyer. The Centric Ceramics are for street use only. For track use, please read the detailed information on the various G-LOC brake pad compounds here.


      Brake Lines : For those of you tracking your cars, we recommend that you upgrade to the Vorshlag S197 SS Braided Brake Line Kit, which includes new stainless steel brake lines for all four corners of your car. That's right - the front flex lines and the rear lines. More information on the Vorshlag S197 SS Braided Brake Line Kit can be found here. Of course you can re-use the original brake lines, as they will fit the new caliper location.