Cheetah Cars, Holden HQ-HZ based kit cars

TB5 - Technical Bulletin 5

Front Brake Calliper Options

HQ Holden PBR cast iron front brake calliper.Over the HQ-HZ series, several front brake calliper options were used, mainly in an effort to reduce unsprung weight.  The original cast iron PBR callipers weigh 5 kg each.

Excluding the WB utes, the calliper styles and suppliers were as follows;
HQ - PBR cast iron
HJ - Girlock cast iron
HX - PBR alloy/cast iron
HZ - Girlock alloy/cast iron

There is nothing wrong with the cast iron items, and they are often the recommended choice because they don't flex,  but for those wanting to reduce unsprung weight, the alloy/cast iron units offer a 1 kg lighter alternative.

The images below are of HX PBR alloy/cast iron callipers.  They aren't the prettiest looking units available, the HZ Girlock alloy/cast iron, in our opinion look better.

If you do change callipers, even though the HQ flexible brake hoses will fit, at full suspension droop when jacking up the car, the hoses will be stretched.  Replace with the items that match the callipers you are fitting.

HX Holden PBR alloy/cast iron front calliper
As an example of what can be fitted, the images below are of Australian sourced modified VT Commodore callipers fitted to an HQ stub axle.  They are alloy two pot units.

The installation includes separate hubs and 296mm grooved discs.  This setup, with VS Commodore grooved solid discs fitted to the rear, allowed the Cheetah to brake at the same braking point as Lotus 7 replicas on the back straight of Pukekohe raceway, (on the earlier circuit without the three quarter-straight dog leg).