Here are some FAQ's about silicone. It fits my needs well however, if you are in competitive motorsport then I do believe the "racing type fluids" are the way to go.
Question
What is so special about DoT5 Silicone Brake Fluid? What does the DoT reference signify? Will it catch fire? Will it damage paintwork? At what point will it boil? How long can I keep it?
Answer
Brake Fluids and the rubber components in braking systems will usually be "DoT" rated. This is an abbreviation for the US Dept. of Transportation who have in fact defined the standards most producers adhere to. Most brake fluids are DoT3, DoT4 & 5.1 Polyglcol fluids ('glycol for short) though some Citroens use Mineral fluid. Our Silicone Brake Fluid is DoT5 and unlike 'glycols, it never needs replacing because it repels moisture. Because it repels moisture it lasts indefinitely - reduces corrosion and ensures the boiling point remains 'high' at 260c (500f) Unlike 'glycol fluid, Silicone will not damage paint. It will not catch fire easily and it's non toxic with no known harmful affects.
Question
Will it improve the performance of my brakes? Will I feel a spongy pedal?
Answer
No, except insofar as the benefits described above. If in fact you do feel a spongy pedal or in fact any other peculiar effects then it would suggest the bleeding process has not been carried out properly, or some other problem exits. AP Lockheed and Girling list many reasons for "spongy pedals" and none of them relate to the use of Silicone Brake Fluid.
Question
Who uses it as original equipment?
Answer
Nobody that we know of except Harley-Davidson in their bikes. It is more expensive than normal fluids and probably because of this no Vehicle Manufacturer seems ready to use it. The US Army use it exclusively in all their lighter vehicles as does the US Post Office. Silicone Fluid has a viscosity which is virtually stable, which in practice means it performs well through most temperature extremes - and that can make a lot of difference in very hot or very cold climates.
Question
Does it mix with other Dot rated fluids? Is it compatible with grease used in the system?
Answer
Silicone DoT5 Fluid will work safely in a system with other DoT rated 'glycol fluids should they become mixed, in fact it is compatible with all other DoT rated products. But be warned - if other non-rated products such as petrol,
oil or greases are in contact with the fluid - who knows? The message is clear. Avoid using not approved i.e.. non-DoT rated products.
Question
Will water collect in pockets in the system? How do I bleed the system?
Answer
Water can only collect in the system if it has not been 'bled' properly. Do the job again following the Vehicle Maker's instructions.
Question
Do I need to rebuild my braking system before I use SBF? Do I have to change the Hoses or seals? How do I flush the system? Can I reuse fluid that has been through the system?
Answer
No you do not have to rebuild your brakes before using Silicone Brake Fluid - We never have - and we have had two vehicles go to 250,000 miles on it without needing a replacement cylinder or calliper. Of course it makes sense to ensure your hoses and other components are in good order - change them if you are in doubt - but best of all get the Silicone in early in the life of the vehicle. Do not be tempted to use any 'flushing agent' None that we know of are DoT rated (item above) and DO NOT be tempted to reuse fluid which has already been through a system no matter how clean it may seem.
Question
Can I use it in an ABS System?
Answer
We have used Silicone in a BMW 728i and a Rover 820si for more than three years. Both vehicles are equipped with ABS and both have now done around 100,000 miles without any problems and without the need for the 'expensive' regular fluid changes. Some dealers charge as much as £100 for this work
Question
Can I use it for racing?
Answer
Silicone Brake Fluid is not a racing fluid and we certainly would discourage it's use for serious racing service. However some owners use it for amateur club events in vehicles they drive to the track and for rallying and they report good results. There are special 'racing fluids' optimised for that application - but they are not Silicone.
Question
Why is it purple or why has mine gone Green/Yellow?
Answer
Silicone DoT5 is dyed Purple and that is part of the DoT rating requirements to differentiate it from other fluids. Sometimes after exposure to air, the purple dye might bleach out and the fluid will look green or yellow. This change is purely cosmetic and it in no way affects the performance of the fluid.
Question
How much will I need to fill the system?
Answer
A litre will be sufficient for most vehicle brake and clutch systems.
I hope this helps resolve some of the mysteries about silicone.
Hersh
