DBA Brakes for the Pontiac GTO: Which Parts Fit

By Core Brake Parts Tech Team — Circleville, OH warehouse

DBA fits the 2005-2006 Pontiac GTO at the rear axle: the 4000 Series HD plain rotor (DBA42021) and the Street Series T2 slotted rotor (DBA2021S) both replace the factory vented rear rotor that arrived with the 6.0L LS2 cars. Before you order, confirm whether your GTO is a 2004 with solid rear rotors or a 2005-2006 with vented rears, because the parts are not interchangeable across that line.

How the 2004-2006 GTO Brake System Changed

The modern GTO ran for three model years, and the brakes did not stay the same. The 2004 car used the 5.7L LS1 with a smaller brake package and solid rear rotors. For 2005, Pontiac moved to the 400 hp 6.0L LS2 and upgraded the brakes to match. Pontiac's 2005 material describes "larger brake rotors, calipers and pads," with red-painted calipers and a GTO logo on the fronts. Period coverage of the 2005 changes also notes larger front rotors and caliper hardware borrowed from the Corvette.

That split is why you will see GTO brake parts listed two ways: "5.7 with solid rear rotors" for 2004 cars and "6.0 with vented rear rotors" for 2005-2006 cars. A vented rotor has two friction faces joined by internal vanes, so air pumps through the middle as it spins. A solid rotor is a single plate. They differ in thickness, so a pad, rotor or line kit built for one year group will not necessarily fit the other.

The quick way to tell which you have: check the model year on your registration, or look through the rear wheel at the rotor edge. A vented rotor shows a gap with vanes between the two faces; a solid rotor is one continuous band of iron.

DBA Rotors That Fit the GTO

Disc Brakes Australia (DBA) is a fitting brand for this car, since the GTO was built in Australia on the Holden Monaro platform. For the 2005-2006 GTO, we carry two DBA rear rotors:

• DBA 4000 Series HD plain rear rotor DBA42021 for the 2005-2006 GTO - a smooth, OE-look face on DBA's upgraded 4000 Series casting.
• DBA Street Series T2 slotted rear rotor DBA2021S for the 2005 GTO - DBA's daily-driver line with CNC-machined slots.

DBA's published dimensions for these rear rotors line up with each other, which confirms they are built to the same factory mounting:

DBA rotors are sold individually, so order two for a rear axle. The slotted T2 is directional: each rotor is made for one side of the car, and the slots must sweep the correct way when installed.

4000 Series HD vs Street Series T2: Which One

Both rotors use DBA's Kangaroo Paw ventilation, a pattern of 144 diamond and teardrop pillars in place of straight vanes. DBA states it gives up to 30 percent more surface area and a 20 percent improvement in cooling efficiency compared with a traditional straight-vane design. The difference between the two is the casting grade and the face.

4000 Series HD. DBA positions the 4000 Series for drivers who want braking "above and beyond standard OE levels." It is cast from high-carbon alloyed iron and put through DBA's Thermal Stability Profiling heat treatment, which the company says improves rotor stability and durability. The HD variant keeps a smooth, OE-style face. It is the pick if your GTO sees hard street driving, autocross or towing a heat load down long grades, and you want no slot noise or extra pad wear.

Street Series T2. The Street Series is DBA's direct-replacement line for daily drivers. The T2 slots are CNC-machined in a bi-symmetrical pattern that DBA says gives a quieter, more responsive pedal and more exit points for pad dust and gases, which improves pad bite. It is the pick for a daily-driven GTO where you want a slotted look and a sharper initial bite without moving to a heavier-duty casting.

If you drive the car mostly on the street, the Street Series T2 is plenty. If the rear brakes get hot, or you plan track days, the 4000 Series HD is the stronger rotor.

Parts to Replace at the Same Time

New rotors should get new pads. Bedding fresh pads onto fresh rotors gives an even transfer layer and avoids the vibration that comes from old pad material on a new surface. For the GTO, we carry pads matched to each year group:

• Hawk HPS 5.0 rear pad set HB573B.615 for 2004-2006 GTO - a street performance compound.
• EBC Redstuff ceramic rear pads DP31711C and EBC Redstuff front pads DP31721C for the 2004 5.7L car with solid rear rotors.
• EBC Yellowstuff street and track rear pads DP41711R for the 5.7L solid-rear car.

DBA does not appear in our GTO front rotor lineup, so for the 2005-2006 front axle we carry the EBC GD7299 GD Sport slotted front rotor pair for the 2005-2006 GTO 6.0. Pairing slotted fronts with a DBA T2 rear keeps the look and feel consistent across the car.

A rotor job is also the right time to swap rubber hoses for braided lines. Rubber hoses expand under pressure as they age, which shows up as a softer pedal. We carry the Russell 692320 stainless braided line kit for 2005-2006 GTO and the Russell 692310 kit for the 2004 GTO. The year split matters here too, since each kit is built for its own model years. New lines mean a full bleed, so plan on fresh fluid of the type printed on your master cylinder cap.

Going Bigger: The Wilwood Rear Kit

If a stock-size rotor is not enough, the Wilwood 140-8754-DR DynaPro rear big brake kit replaces the rear calipers and rotors outright. Wilwood lists it with four-piston DynaPro radial-mount calipers, 12.19-inch drilled and slotted rotors 0.81 inches wide, and retained function of the factory parking brake. Wilwood notes it may fit some 15-inch wheels and tells buyers to check the wheel clearance diagram in the instructions before purchase. It is a bigger job and a bigger change in brake balance than a rotor swap, so it suits cars that already have front brake upgrades.

How Hard Is the Job

A rear rotor and pad swap on a GTO is a driveway job for someone who has done brakes before. The caliper and bracket come off, the rotor slides off the hub, and the parking brake shoes inside the rotor hat may need to be backed off if the rotor drags on removal. Clean the hub face of rust so the new rotor sits flat, torque the caliper bracket bolts and lug nuts to the values in the factory service manual, and follow the pad maker's bedding procedure. Braided line installs add a bleed and are best done with a helper or a pressure bleeder.

Browse all options in our brake rotor collection and brake pad collection.

Frequently Asked Questions

Does DBA make a rotor for the 2004 Pontiac GTO?

The DBA rotors we carry for the GTO are listed for the 2005-2006 cars with vented rear rotors. The 2004 car uses a solid rear rotor, so check fitment by year before ordering. For 2004, we carry EBC pads built specifically for the solid-rear setup.

Can I use a slotted rotor on a daily-driven GTO?

Yes. DBA builds the Street Series T2 for daily drivers, and the slot pattern is designed for a quiet pedal. Slotted rotors can wear pads slightly faster than plain rotors, which is one reason DBA also offers the plain 4000 Series HD.

Do DBA rotors come in pairs?

No. DBA sells rotors individually, so order two for one axle. The T2 slotted rotor is directional, so make sure you get a left and a right.

Why are 2004 and 2005 GTO brake parts different?

Pontiac upgraded the brakes for 2005 alongside the 400 hp LS2, with larger rotors, calipers and pads, and vented rear rotors in place of solid ones. The 2004 car kept the smaller package.

Do I need new brake lines when I replace rotors?

Not required, but if the rubber hoses are original they are likely due. Braided lines reduce hose expansion, giving a firmer pedal. Use the kit matched to your model year.

Sources

1. DBA - Rear 4000 Series HD Brake Rotor DBA42021 - diameter, thickness, minimum thickness, height, center bore, 2 per axle
2. DBA - 4000 Series Brake Rotors - Kangaroo Paw ventilation figures, high-carbon iron, Thermal Stability Profiling
3. DBA - Street Series Brake Rotors - daily-driver positioning and T2 slot description
4. DBA2021S product specifications - T2 rear rotor dimensions and 2005 GTO rear fitment
5. 2005 Pontiac GTO overview - conceptcarz - larger rotors, calipers and pads for 2005, red calipers with GTO logo
6. 2005 Pontiac GTO Fact Sheet - Over Drive Magazine - larger front rotors and Corvette-sourced caliper hardware
7. Wilwood - Rear Brake Kit 140-8754-DR - caliper, rotor size, parking brake retention, wheel clearance note