More on Silicone Brake Fluid

[Nick <nicko@domain.elided>]

HI all,
	the above topic has always been of interest to me personally, generally because I have only ever owned 2cnd hand cars and this is unlikely to change in the near future.

For what is worth, here is my 2 cents worth:

I have always thought that if I had the chance to retrofit silicone brake fluid (SBF) to a worthwhile car, I would - even thought the stuff is priced like liquid gold. The driving ambition is 'maintenance free' motoring from the hydraulic part of the brake system....

About 15 years ago a friend of mine in Wollongong started a rebuild on a rather are beast in Oz, namely a Trident Venturer V6. He changed all flexible lines, rebuilt all brake part seals and installed Silicone fluid. 

Granted the car only got back on the road circa 2 years ago, but it still has the same fluid! No leaks, no problems to date....

My experience has been that in changing the brake fluid in a few cars over the years, especially cars over say 5 - 7 years, you actually do more damage to the master cylinder especially, by forcing the seals to over travel parts of the bores already corroded usually with catastrophic effects weeks later, ending in the need for a re-built master cylinder.

With hind sight I have now decided simply to keep an eye on the fluid level(s) and don't touch until the fluid starts escaping. In newer cars this seems to work for 5 - 10 years depending on the initial vehicle quality and brake fluid quality!

As far as why most car manufacturer's don't supply as standard? In the first case the fluid performance specs are far above what is actually required in conventional motoring... Quite apart from the fact that stuff can cost A$150/L and you always seem to need  2 bottles....

In manufacturing, any unit costs you can minimize or eliminate can make a huge difference to per item profitability. This is especially so with cars where there is intense competition these days.....

Given the above, my 11/75 Stag was totally mechanically rebuilt last year. (My wallet is still whimpering.......) It is now setup for unleaded fuel but as I have no cats at this time is still running leaded fuel...

In having the brake system completely overhauled I took the plunge and requested conversion to Silicone. The product supplied was Castrol (UKs) Racing Brake Fluid. Certainly the cost upfront is as indicated above. What has surprised me however is that the bottle instruction still seem to indicate a need to change fluids regularly to ensure performance. I am told though this is only necessary in racing vehicles due to the intense 'abuse' of the braking system during competition. At this stage I have no intention of changing same unless there is a problem...

Sadly though the conversion has not to date been totally successful. For reasons I don't understand although all wheel cylinders and the circuit failure sensor and block seem to handle this product well, my brake master cylinder unit has not.

I am now on my 2cnd exchange rebuilt unit and it is still leaking (ingesting fluid)! Needless to say, I am less then impressed at this time and am currently awaiting follow up with Castrol's technical department and the brake specialist who has in good faith now rebuilt me 2 units.. Interestingly another contact through the TSOA car club in NSW has abandoned this high tech fluid for the very same reason.

I would welcome any feed back at all on this problem and will let the digest know what the final outcome is in due course.

kind regards,

Nick Berlyn