Part II: Rear Brake Installation
Many hobbyists increase their Pontiac's horsepower output in search of "the number," with less concern on the braking system. However, since we have installed a few bolt-ons and started taking our '05 GTO out to local autocrosses, it has become apparent that the factory brakes could use some improvement.
With a bit of research and weighing the pros and cons of a big-brake kit, we concluded that the factory brake calipers are strong and have proven to be reliable in similar high-performance applications. We decided instead to upgrade the rotors, while retaining the same overall diameter, and employing high-performance pads and hoses.
The most attractive element of sticking with the factory calipers is the lower cost versus the expensive big-brake kits. We upgraded to DBA 5000- and 4000-series rotors with Hawk HPS pads and Russell stainless lines. The DBA front rotors are part number 52020BLKSL and 52020BLKSR, and retail for $1,056 per pair (only sold in pairs). Rear DBA rotors sell for $165 each or $330 per pair (PN 42021SL and 42021SR). Russell's lines (PN RUS692320) are $140 and the Hawk HPS brake pads (PN HB247F.575, front; PN HB573F.615, rear) cost $70 and $90, respectively. Finally, we replaced the old fluid with AmsOil Series 600 High Performance DOT 4 brake fluid, which has a boiling point of 580-degees Fahrenheit.
So if you're just joining us for Part II, we tackled the front brakes in Part I and we'll move onto the rear and then properly bed in the pads. Once we're done, we will complete our testing to measure any improvements.
 Here are the rear brake upgrade...  Here are the rear brake upgrade components we installed on our '05 GTO. DBA's rotors feature a "Kangaroo Paw" vane design that the company says allows the rotor to run cooler, be stronger, and outperform straight-vane disc rotors by as much as 20 percent. Hawk Performance's HPS street pads were chosen to shorten stopping distances without beating up the rotors, and the Russell brake lines will help ensure proper brake-pedal pressure and eliminate the risk of the lines expanding under high-thermal loads. |  Unlike the 5000-series rotors...  Unlike the 5000-series rotors we installed on the front, the 4000 series rears aren't two-piece. They also use the company's 6x6 wiper slot design, which is less aggressive. |  The OEM ventilated 11.3-inch...  The OEM ventilated 11.3-inch rear disc brakes do not feature slotted rotors. |
 Pete Epple, associate editor...  Pete Epple, associate editor for Muscle Mustangs & Fast Fords, also helped us with the rear brakes. Just like the fronts, the rear calipers and bracket are held down by two bolts each. Pete removed the caliper from its bracket with a 15mm wrench. |  He then removed the caliper...  He then removed the caliper bracket with a 19mm wrench. |  We found the rear control...  We found the rear control arms to be an ideal location to rest our calipers. Letting them hang by the hoses is a no-no, as they could be damaged. |