Stopping Power – a look at Facel brakes

Stopping a big Facel, or even a small one, takes a lot of power because of weight – lots of weight. Club members will know that I bang on about the fact that the Facel factory never seemed remotely interested in weight saving. I have written several articles in FaceLetter in the past, drawing attention to items like the heavy steel fabrication of the heating system, and the the cast iron mounting for the brake/clutch pedal, both weighing several times more than necessary, even with the materials available at the time. Yes, we are grateful more than forty years down the line that all Facel chassis were built on locomotive principles and last forever, but couldn’t more body parts have been made of aluminium?  I have forgotten the physics, and someone in the Club will no doubt remind me, but I think that kinetic energy increases at something like the square of speed. Anyway, what this means is that a big 35 cwt Facel travelling at 100 mph takes a lot of stopping…
The early cars had drum brakes and they were totally incapable of doing the job. Very few UK owners will have this problem as it was only with the HK500 that serious import numbers built up. It was W.O.Bentley who, in the heyday of the vintage Bentley, when criticised about the lack of stopping power of his cars (even more marked than that of the Facel) famously retorted: “I make my cars to go, not to stop”. This could however equally be said of Facel Vegas in the drum brake days. Fred Hobbs, in charge of servicing (and sometimes importing) the cars for the concessionaires HWM, through their subsidiary Intercontinental Cars, felt that the drum brakes were: “Hopelessly inadequate for very high speeds. Not only did we have very unpleasant moments while trying to stop the car from speeds of over a hundred miles an hour, but the heat generated in the drums was such that they lasted no time at all. It was obvious that discs were going to be needed.” Indeed, when the first Dunlop disc brakes became available, Fred had them retro-fitted to all the early HK500s. They were a huge improvement. However, these were disc brakes in their infancy. Not only were they very small in comparison with modern ones, but the design and materials left quite a lot to be desired. If set up well, they do quite a good job – but because the cylinders are not made of stainless steel (as became the standard later) they are prone to corrosion when the car is left standing. The brake fluid being hygroscopic, picks up water which provides the corrosive element and the result is usually that the piston sticks in the cylinder – either “on” or “off”.  The result is that the car will either not stop, or will not move at all. This effect is exacerbated by the design as there is a central locating pin for the piston. This is not used on modern systems at all, and only makes matters worse when corrosion has set in preventing the withdrawal of the piston to the “off” position. The very strange servos fitted to Facels can also cause the brakes to stay on when the release mechanism ceases to function. The answer is to re-build the callipers with stainless steel inserts and replace the servo. The Club can put members in contact with firms that can help.
If you’re rebuilding your Facel brakes, there is another very worthwhile upgrade. Modern cars, unlike those of the 60s and earlier, have a split system front and rear, so that if one should fail all braking power is not lost. Rolls Royce experimented at one time with a diagonal arrangement (i.e. the nearside front was coupled to the offside rear) but they reverted to the separate front and rear arrangement too. This is not too difficult to install with twin master cylinders and is an excellent idea.

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