Brake Rotors

Updated February 26, 2000

BIG ROTOR UPGRADES
The larger the rotor diameter, the less caliper pressure (force) is needed to provide the same stopping power. Constant pressure = greater stopping power.

BIGGER Front Rotors
1988 to early-95 W-Body (all)
Your existing front rotors are 10.5" in diameter. You can upgrade to the 11.25" front rotors which were standard equipment on late-95 and newer gen 1 W-body cars. This involves replacing your existing strut/knuckle assembly with the newer version, and installing the larger rotors. Your old calipers and brake pads will transfer over. The only thing that was changed is the metal plate on the front of the knuckle that the caliper bolts onto, but since it is welded on, the whole knuckle needs to be changed. This is not a difficult upgrade if you swap the entire assemblies complete with springs, otherwise, you will have to have a shop transfer your springs over unless you happen to have spring compressing equipment. You will need the following:

RH Knuckle (includes strut), GM Part #22064590, retail price $234.12.
LH Knuckle (includes strut), GM Part #22064591, retail price $234.12.
11.25" rotors (2 required), GM Part #18021389, retail price $134.64/each.

Parts are available at your favorite GM Parts Dealer. If you would like to save money, I highly recommend buying these parts used from a salvage yard. The following cars are suitable donors:

Late-1995 to 96 Buick Regal
1995-99 Chevrolet Monte Carlo/Lumina
Late-1995 to 97 Oldsmobile Cutlass Supreme
Late-1995 to 96 Pontiac Grand Prix

Be careful when using a 95 model year W-body as a donor, as many early 95's did not have the larger front rotors and redesigned knuckle/strut assembly.

BIGGER Rear Rotors
1988-93 W-Body (all)
Your rear brake rotors are 10.1", and your calipers downright suck. The sliders tend to seize, which also causes your front rotors to warp. Many people have found the best solution to be upgrading to the 94+ rear brake system. The 94+ rear brake system utilizes a totally different rear caliper design, and 11" rear rotors. It will bolt onto your existing knuckles, and only minor modification of brake lines is required. You will need to get the rear calipers, caliper support brackets, brake pads, rotors, park brake cables, and the bolts that hold the caliper support bracket to the spindle. Here are detailed instructions to explain how the upgrade is performed:

How to upgrade a 1988-93 W-body to 94+ rear brakes.

Aftermarket BIG Rotor Upgrade Kits (12" and larger)
They just plain don't exist for gen 1 W-body cars. To get any larger front rotors than the 95+ factory 11.25" rotors will require custom fabricating of a different caliper mount bracket to the knuckle/strut assembly. Same goes for the 94+ 11" rear rotor. Perhaps a nice setup would be custom fabricated mounts for PBR 4-piston calipers and 13" rotors.

FANCY ROTORS
There are many types of fancy rotors. The main purpose of fancy rotors is to improve cooling and reduce brake fade under high-demand applications. Fancy rotors also serve a secondary purpose of looking cool and impressing those who can see them through open-spoke wheels. There are several types of rotors.

Cross-drilled - These rotors have holes drilled in them to improve cooling and brake pad outgassing. They are designed to prevent rotor warping, and will also prevent brake fade due to high temperatures. A possible drawback is that they can increase brake pad wear. In some extreme cases, they have also been known to crack and damage other brake parts such as calipers.

Option 1: Eurorotor has cross-drilled rotors for W-body cars. Here are some pictures of the Eurorotor cross-drilled rotors courtesy of Kevin Heider.

Front Rotor

Rear Rotor

Front, 88-93 style (10.5"), silver cadmium plated, drilled Eurorotor on a 90 GP. The caliper is painted with Aluminum colored high-heat paint from an auto parts store. The rotor is is listed at http://www.cyberauto.com under Chevy Lumina and Pontiac Grand Prix. It is part #5566-CD, $77.94ea. The plating is an extra $15 each. Rear, 94+ style (11"), silver cadmium plated, drilled Eurorotor on a 90 GP. The caliper is painted with Aluminum colored high-heat paint from an auto parts store. The rotor is is listed at http://www.cyberauto.com under Chevy Lumina and Pontiac Grand Prix. It is part #55110CD at $100.10ea. The plating is an extra $15 each.

They are available from:

Cyberspace Automotive Performance.

late 95-99, w/286mm (11.25") front disk

Front, 55109CD, $96.53ea

Rear, 55110CD, $100.10ea

94-early 95, w/267mm (10.5") front disk

Front, 5566CD, $77.94ea

Rear, 55110CD, $100.10ea

88-93

Front, 5566CD, $77.94ea

Rear, 5567CD, $80.08ea

Option 2: RS Motorsports sells cross-drilled rotors, which I believe were manufactured in house. I know they have them for 88-93 W-body, but not sure if they offer the larger rotors for newer cars. They are $82/each.

Slotted - These rotors have diagonal slots cut into the face of the rotor, about 1/8th inch deep improve cooling and brake pad outgassing. They do not provide as much cooling capacity as cross-drilled rotors. They are designed to prevent rotor warping, and will also prevent brake fade due to high temperatures. I do not know of any applications for first-gen W-body.

Dimpled - These rotors have full radius milled dimples that provide similar benefits to cross-drilled or slotted rotors, but they are not susceptible to the cracking that may occur with cross-drilled rotors.

Option 1: Dimpled rotors are available from Grob-Till Industries, Inc.

95-99 first-gen W-body with 11.25" front rotors, part #75-8254 (front) and 75-0277 (rear).

88-94 W-body, part #75-0275 (front) and 75-0277 (rear).

Each kit includes a pair of rotors and pads. Each kit costs approximately $500. Careful when you order - their Application Catalog doesn't seem to take into account that 94-99 first-gen W-body with rear disc brakes have a different size rear rotor than 88-93.

Cross-Drilled + Slotted - The fanciest of all fancy rotors? These rotors are both cross-drilled and slotted!

Option 1: GM DuraStop cross-drilled and slotted rotors. There is an application for all 1988-early 95 W-body front rotors and 1988-93 rear rotors.

Part numbers for the rotors:

18038519 front (10.5" front rotors)

18038520 front

18038523 rear (10.1" rear rotors)

18038524 rear

I believe the multiple part numbers is because they're directional and you need different ones for right and left. They are very expensive, the prices (retail) are: $333 (each!) for the front rotors. $247 (Each!) for the rears.