After have another whinge to the Mrs, I decided to get the rear brake setup off the rear of a VP commodore. They needed a bit of work so I ordered new kits and pistons, sandblasted and overhauled to like new.

DSC_0101[4341].JPG DSC_0120[4381].JPG

Due to engine performance a 9" diff is under the rear and of course the brakes wont fit, so I had to make some adaptor plates to mount them to. Bit of stuffing around but a day on the mill and lathe does wonders. Got rid of that horrible hydraulic park brake setup and now have the commodore inner disc shoe setup. Unless your racing your car you don't need ventilated rear disc rotors, the rear only does around 30% of the braking and doesn't generate a lot of heat.

DSC_0104_1.JPG DSC_0105[4342].JPG DSC_0121[4380].JPG DSC_0122[4379].JPG

I decided to do a weigh in between the old and new brakes. The front weighed in at an extra 1kg per side, but the new Simmons wheels saved me 500g per side so the front unsprung weight has increased by 1kg. Even better the rear brake weight saving is an astonishing 15kg lighter.

DSC_0130[4414].JPG DSC_0111[4370].JPG DSC_0131[4415].JPG

New wheels look awesome.


DSC_0100[4339].JPG

There are a few things to consider when doing a brake upgrade.

As I have mentioned earlier its easy to get carried away with big numbers and loads of caliper pistons. I have matched front to rear and I can lock front and rear brakes almost at the same time, front locks just before the rear. My front brakes lock at close to 1,200 psi hydraulic pressure.
Consider the weight of the car. There is no real point of adding near 1,900kg VF commodore brakes to a 1,400kg early Holden. Brake master cylinder, brake boosters and brake pedal pivot points all need to work together to produce the magic number of around 1,200-1300 psi hydraulic pressure with moderate pedal pressure. By choosing all the components from a late model car of comparable weight is the best starting point. The engineers have done all the hard trial and error for you. Its interesting to see that my F80 BMW M3 which weighs in at 1,500kg only has 4 pot calipers front and 2 pot rear. You only have to breath on the pedal and your stopped, the Mrs reckons their good but in my opinion its to easy to send you through the windscreen and a savage, you need to get the feel of it quickly or its bruised forehead. So think twice before handing over that hard earned cash on brake kits that can be dangerous, expensive or just bragging rights down the pub with no extra benefit.

In the end I spent under $900 to do the front and rear brake upgrade plus rims and tyres. My first impressions from the first drive is my brakes feel 40% more efficient.