Them's The Brakes - Blackbourn 377

By: Rob Blackbourn

Date: 08.06.2017

Our man Blackbourn on a revolutionary braking system that stopped before it got started

From Unique Cars issue #377, July 2015

There was a lot to like at the Shifting Gear exhibition put on in Melbourne by the National Gallery of Victoria, celebrating Australian automotive design expertise. And you didn’t need to be an automotive design graduate to enjoy it, just an Aussie-car enthusiast.

For me the Holden Efijy concept car dominating the foyer display was a great opener. I’ve seen it before, but this time I got to appreciate more of the exquisite detail. Truly magnificent.

What followed in the network of separate exhibition spaces didn’t disappoint. There was a succession of top-shelf individual vehicles – a really interesting blend of the familiar and the less so, including factory muscle cars, one-off race cars and some unique road vehicles that have never seen a racetrack.

There were several blasts from my past including GMH and Ford muscle cars that I’d been involved with during my 10 years in the industry in the amazing days from the mid-’60s to the mid-’70s. And the late Lou Molina’s gorgeous Monza race-car was a standout. Its voluptuous red bodywork is as beautiful as ever. Perhaps better. Its sexy styling and the stunning performance from its blown, Repco-headed, ‘grey’ Holden motor, made it a favourite of mine as a teenage motorsport fan. Actually I almost wore the Monza at the top of ‘The Wall’ at the Templestowe hillclimb when Lou miscalculated on one run and slid nose-first into the star-stake and chicken-wire fence I was hanging over.

The recently restored Holden Hurricane concept car brought back strong memories. I worked on an ill-fated production-car project that now only survives in the Hurricane. It was the oil-cooled front-brake set-up intended for the HT 350 Monaros in ’69.

| Review: Holden Hurricane

The plan was to use a ‘wet’, multi-disc brake that would be fade-free and pretty much wear-free. How good would that have been for Bathurst? It was a proven braking concept in specialised aircraft, truck and industrial equipment applications – but quite new for cars. Apparently GMH had picked it up from GM’s now-defunct Oldsmobile division in the US where development was already underway.

Overall it’s similar to a motorcycle clutch, featuring a pack of discs that are alternately keyed to the rotating drum-like housing and the fixed stub-axle (or backing-plate), while having some axial-movement freedom. Hydraulic pressure applies the braking force by squeezing the pack of discs together axially. The cooling oil, contained within the pair of sealed drums, was circulated through separate oil-radiators mounted behind the front bumper to dissipate the heat energy generated by hard braking.

My task was sourcing the manufacture of a heap of precision fixtures and gauges with specialist companies to facilitate the correct assembly of the new and complex front brake units. It was essential that tight tolerances be maintained to ensure proper function and also the oil-tightness of the assemblies.

Suddenly the fat lady sang unexpectedly and it was all over.

Pre-production brake failures at the Lang Lang proving ground coupled with advice that Oldsmobile had already canned the project led to its demise here. Cancellation costs for my small part of the project alone were huge.

It was generally agreed that the limited development period available to have the brakes fully sorted in time for Bathurst had been woefully inadequate for an exercise of this complexity. But it was exciting to be part of it while it lasted.

What was also generally agreed was that the Holden Dealer Team was dead lucky winning in ’69 with the HT GTS Monaro (featuring conventional brakes). But for an amazing number of tyre issues, Ford’s faster GTHO would almost certainly have pulled it off.

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