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Brake Fluid


DMC90

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Has anyone investigated the possibility of changing from the standard Dot 3 Brake fluid to Silicone Dot 5? Standard Dot 3 brake fluid is known to absorb water and one of the advantages of changing to the more costly Silicone Fluid is that it doesn't! confused.gif" border="0

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Lots on the www when you do a search. Most read as follows...<BR>"WHICH BRAKE FLUID IS RIGHT FOR YOU? <BR>Glenn Goodspeed (December, 1996) <P>Some folks claim that because silicone brake fluid (Dept. of Transportation #5) does not absorb water, it will keep moisture from collecting in the brake hydraulic system. DOT 3 and DOT 4 fluid, being alcohol-based, may indeed absorb water from the air, but not fast enough to warrant switching to DOT 5. <P>Even a hydraulic system that contains silicone fluid may collect water when moisture condenses on the roof of the master cylinder and drips into the fluid below. Since water is heavier than silicone fluid, it sinks to the bottom of the cylinder and is sucked into the rest of the system. Over time, the whole system may become polluted in this manner. <P>If you doubt that this can happen, I invite you to open a transmission that has sat unused for several years. You will be able to pour out a quantity of condensed water in addition to the transmission oil. <P>I believe the only way to make sure your brake lines and internal parts are clean and water-free is to bleed the system with fresh fluid about once every year. It only takes about an hour with a one-man brake bleeder and about $5 worth of fluid. <P>If you just can't resist trying silicone fluid, remember that you must flush the hydraulic system completely with the new fluid to remove all the old fluid. It is a good idea to replace all the seals and clean internal parts in the calipers and cylinders, too. A lot of work for a dubious return." <P>Even of more concern Silicone also has slightly different physical properties and compressibility, making it unsuitable for ABS systems calibrated to work with DOT 3 or 4 brake fluid.<P><B>Don't even think of it.</B>

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<B>DO NOT USE THE SILICON FLUID!!!!</B><P>A bit of reading on the subject should explain. The last few posts here are prob the most informative: <A HREF="http://www.aaca.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=002126" TARGET=_blank>http://www.aaca.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=002126</A> <P>Bottom line: <B>DON'T DO IT!!!</B><p>[ 10-16-2001: Message edited by: Consultants_1 ]

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I have mixed feelings about using DOT5 silicone in a road-going car. It's true that the non-hygroscopic (use that in scrabble and you'll clean up nicely) nature of silicone can be a problem because the water builds up in places and may *accelerate* corrosion. But...<P>In the 80s, my Dad and brothers and I were suffering through an amazing number of brake part replacements on our K-car. (Don't laugh - I didn't pay for that car, and it had the solid 2.2L motor). After flushing and converting to DOT5 fluid, with regular maintenance, no other part of the system ever failed, even with extremely hard miles at the hands of 3 teenage brothers.<P>But that was a standard braking system. ABS systems have pumps and fine metering orifices that are not compatible with silicone fluid. Passing DOT5 through a small orifice apparently causes foaming. frown.gif" border="0 <P>Mr. Teves states: "Use ony DOT-3 brake fluid. This system was designed for use with DOT-3 brake fluid. DOT-3 brake fluid has better lubricating qualities than DOT-5 brake fluid. If DOT-5 brake fluid is used in this system, it may cause the hydraulic pump to fail. Never use DOT-5 brake fluid in this system regardless of what any DOT-5 brake fluid container might have printed on the label"<P>The high price tag printed on the label may also deter you.<P>Too bad DOT5 is not the solution in the Reatta - we just can't get around keeping the fluid fresh. blush.gif" border="0

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Curator,<BR>First thing you should do when you buy any car is to check over the brakes and tires--your life is riding on them. There has been many posts about the Reatta brake system on this forum. Stick to the basics problems first then have a good mechanic that is familiar with the "TEVES" brakes sytem do the work on it.<BR>ronvb wink.gif" border="0

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