Any disc under minimum thickness will be ineffective in braking situations. Most Commodores from VB through to VP use the same 10 inch front disc, and calliper style. VL Turbo, VN V8 and VP II have an 11 inch front disc rotor. These rotors also use a different calliper, which sits further out to accommodate for the increased rotor diameter, and are cast with extra ridges on the calliper housing, to assist in heat dissipation. Because of the increase in size, 14 inch rims can not be used. Rear disc rotors are the same from VB through to VP, except IRS (Independent Rear Suspension). Rear disc rotors are all solid, meaning that it has no ventilation between the front and back surfaces. There are ventilated discs available for the rear of VB to VP, such as SV5000 and Grp A, and they come with a Corvette calliper.
The downfall of any braking system is heat, and heat dissipation. Slotted or cross-drilled and slotted rotors are beneficial, as they allow more airflow in and around the disc surface, to greatly increase heat dissipation.
Care must be taken when replacing pads, as different compositions of brake material are available. If the brake pad is high in metal, the pad will last longer, but the life of the rotor will be reduced. A brake pad low in metal, therefore being a soft composition, will not last as long as a metal pad, but the stress on the rotor will be less, and therefore the rotor will last longer. Performance brake pads are commonly available, but their operating temperatures vary, and may not be effective when cold.
VT Disc and Caliper Kits
VT twin spot calipers and disc rotors are a common upgrade for the front of earlier model Commodores. VB to VP will require 2 floating hubs for the disc to mount to, where as VR and VS already have a floating hub design and will not need changing.
VT disc rotors should not be used on VR or VS Commodores without the use of a centre slip ring. The diameter of the floating hub centre is larger on VT's, and if fitted without a slip ring, the disc is able to "walk", and not locate correctly. This can cause brake shudder and/or broken wheel studs.
Disc rotors are available for VR and VS Commodores that utilize the VT sizes, but have a smaller diameter hub centre to correctly locate the disc.
An area often overlooked is the master cylinder. VB to VS Commodores had a choice of 15/16inch or 1inch bore master cylinders. This is not suitable for the VT twin spot brake calipers. The VT master cylinder is a 1inch bore master cylinder, but is a quick fill. This means that the first section of the master cylinder is actually larger (1 3/16inch bore diameter). The quick fill design displaces more brake fluid on the initial application, to help move all 4 (front) pistons and maintain a good pedal feel with minimal travel. Without the use of a VT master cylinder, pedal travel will be increased. In other words, your pedal will go further to the floor before the car stops (some ABS vehicles do not suffer from this problem, but only some!!!).
Unfortunately, VT master cylinders will not bolt directly onto earlier model brake boosters. Because of this we sell a brake booster and master cylinder that will fit into earlier model Commodores. Ring us for more details!
Brake line flare ends in VB to VP are known as a double ball flare. From VR onwards they changed to a single ball flare. VT brake lines, brake hoses or master cylinders used in VP or earlier will need to have the flares changed.