2005 Pontiac GTO Brake Upgrade - Speed Slayer

The application-matched PolyMatrix pads were then secured in place. Note that the mounting system is different for the front pads than it was for the rears, as an actual bolt and spacer is used in lieu of a metal clip system. This bolt has a locknut on it, too. Don't overtighten it,just snug it using a 3/16 hex key wrench and a 7/16 open end. Wilwood says this bolt setup also adds to caliper stiffness, and rigidity is one of the highlights of these billet-body, CNC-machined SL6 calipers (it allows high loads to be withstood along with delivering exceptional brake pedal response).

We were left with the simple matter of installing the front brake lines. Though we desperately wanted to reuse the stock bracket holding the line to the frame, the stock rubber line's metal end is seemingly permanently affixed to it. Never fear: a hacksaw can be used to cut flush with the bracket and remove the stock line. Problem solved!

As at the rear, a Wilwood Flexline kit was used for brake line hookup. It is strongly recommended that the braided portion of the line be zip-tied or otherwise secured to the shock in the same location that the factory rubber line used its locking grommet for positive retention. You can see that we have done this if you look closely here.

The completed installation is eye-catching, to say the least, but hopefully the best part will be the improved braking performance! The front brake system install process is then repeated for the other side of the car. Inexplicably, although the hat shown here on the driver side does not have a Wilwood insignia etched into it, our passengerside hat does-you'll see this momentarily. (Now that I have pointed this cosmetic asymmetry out, surely it will drive Bruce nuts!)

The last thing left to do was bleed the front brakes. As during the rear brake bleeding process, one will need to add fluid to the brake reservoir. To complement our new brake system, we're using some of Wilwood's EXP 600 Plus fluid, which the company says is designed to perform under high heat and extreme pressures. Aside from temperature testing that proves this fluid's ability to exceed any DOT or SAE specifications, Wilwood also says its continuing resistance to aeration and compressibility (even after many instances of hard use) allows this fluid to stand the test of time that others cannot. This stuff goes for about $20 a bottle, so we're careful not to spill any!

In bleeding each front caliper, bleed first using the outboard bleed screw (shown), followed by the inboard bleed screw. Thanks to the natural upward movement of air bubbles in a fluid, it is only necessary to use the upper bleeders; ignore the lower ones, just make sure they are tight. (This same advice goes for the rear calipers, by the way.) The front wheels were reinstalled, and we're done!

Here's the proportioning valve that Bruce had installed to remedy our brake bias problem. Wilwood even says in its instructions that bias may be an issue (as is often the case with brake system changes as well as suspension and tire modifications), so you should not be surprised if you have to do the same. Prior to testing, we verified that the rear brakes were not locking up before the fronts, and so were good to go.

As we set up the radar gun that would be measuring our 60- to-0 stopping distances, Bruce adjusted his tire pressures to match those used during baseline testing. As you can see, we opted to perform our test on a deserted rural road, this one actually passing by some of the University of Wisconsin at Madison's agricultural research buildings. About the only disruption experienced during our test session involved some friendly University farmhands driving up in pickup trucks to see what all the fuss was about-and they were rewarded with a look at some spare copies of GMHTP that Bruce keeps on hand at all times.