DonaldSmith Posted April 28, 2011 Report Share Posted April 28, 2011 Sometimes My 2008 Taurus makes a grinding sound when I back out in the morning and step on the brakes. The local shop checked out the brakes - plenty of pad left. The grinding sound may be from rust on the rotors from sitting overnight. No problem, no charge. It has been a good, relliable shop. But they recommended changing the brake fluid since it had turned black - from the copper lines, they said. They recommend changing the brake fluid religiously every 30,000 miles. Hmm. I pose the issue to the gurus here - is black brake fluid bad, and can it get badder? Or is its replacement unnecessary? Quote Link to comment Share on other sites More sharing options...
Young Ed Posted April 28, 2011 Report Share Posted April 28, 2011 I agree with them that it is contaminated and should be bleed until clear liquid comes out. However I don't believe its from copper lines. No way would ford or any other car manufacturer use copper for brake lines. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted April 28, 2011 Report Share Posted April 28, 2011 I agree with them that it is contaminated and should be bleed until clear liquid comes out. However I don't believe its from copper lines. No way would ford or any other car manufacturer use copper for brake lines. Might be the cunifer brake lines that many imported cars have now. A copper-nickel alloy that is rated for brake service and has greater resistance to corrosion than steel. But the lower corrosion part means that it reacts chemically to fewer things in its environment than steel. So I'd expect that brake fluid would not be contaminated by it. Assuming, of course, that Ford uses that type of line. Not a bad idea to flush the brake hydraulic system periodically anyway. Especially if you are using a hygroscopic brake fluid like DOT3. Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted April 28, 2011 Report Share Posted April 28, 2011 No way should it be black, no matter the reason. Change it. Oddly, mine turned green, I never heard of that, but since then I have been checking around and it seems fairly common. I bled the green out and the brake pedal was noticibly firmer and higher up! Go figger. Quote Link to comment Share on other sites More sharing options...
Scruffy49 Posted April 28, 2011 Report Share Posted April 28, 2011 Mine turned into grayish greenish translucent sand. And ate the wheel cylinder pistons. No more DOT 3 for me. Going to install 100% new components and run DOT 5. It stays a beautiful water free purple for years. Luckily one of my Sweptliner friends also carries Pilot House era brake parts (all of them). The more moisture DOT 3 and 4 absorb, the more caustic/corrosive they get. Quote Link to comment Share on other sites More sharing options...
thrashingcows Posted April 29, 2011 Report Share Posted April 29, 2011 As stated above Black fluid is contaminated fluid, and is why pistons seize up in caliper bores etc. I flush my brake fluid every 1-2 years, takes me about 30 minutes to do it all by myself. Since I started doing this the frequency of brake line, caliper and wheel cylinder failure is almost zero. Quote Link to comment Share on other sites More sharing options...
Fluid drive Posted April 29, 2011 Report Share Posted April 29, 2011 It is almost instaneous that conventional brake fluid will turn black when placed in a brand new brake system; what would contaminate it then? It is true that I have never seen copper lines on a factory brake system but the rubber parts in a braking system turn the fluid black in a hurry. The black color alone will not influence the operation of the service brakes. Casteroil-alcohol or DOT-3 fluids are hygroscopic in nature and do absorb moisture through the vent cap in the master cylinder - that's why I have converted every antique vehicle I have rebuilt, and I do mean many !, to DOT-5 or silicone based fluid. DOT-5 does not turn black with use and it has been colored since it's introduction back in the early 70's so that it can be seen in a master cylinder reservoir. An added note; the horror stories that surround the use of DOT-5 are completely false. It only causes problems if the system is not completely free of any old fluid residue. Perhaps your fluid has taken on some moisture? Fluid Drive Quote Link to comment Share on other sites More sharing options...
DonaldSmith Posted April 29, 2011 Author Report Share Posted April 29, 2011 Better safe than, well, you know. Now I'll see how long it takes for the new fluid to turn black. Quote Link to comment Share on other sites More sharing options...
thrashingcows Posted April 30, 2011 Report Share Posted April 30, 2011 Better safe than, well, you know.Now I'll see how long it takes for the new fluid to turn black. Since I do mine regularly, I see some discoloration to the fluid after 1-2 years....but definitely is not anywhere close to being black. Quote Link to comment Share on other sites More sharing options...
Robert Horne Posted April 30, 2011 Report Share Posted April 30, 2011 Regular brake fluid absorbs moisture, turns dark, and even black. If you do not seal a bottle of brake fluid good, the fluid in the bottle will turn dark also, from absorbing moisture. Master cylinders have a vent, that will allow air to enter and escape, and with temperatures going up and down, sweat will occur. If brake fluid did not absorb the moisture, where would the moisture go? Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted April 30, 2011 Report Share Posted April 30, 2011 Nit picking here, I admit. Master cylinders have a rubber gasket under the lid that seals the fluid from air contact. Its folded diaphragm pleats allow the fluid level to drop as it fills the space in the wheel cylinders as the linings wear. So, theoretically, the fluid should not absorb any more moisture than is in the air at the top of the reservoir when you close the lid. How do you spell "theoretically"? and should I even use the word? Quote Link to comment Share on other sites More sharing options...
thrashingcows Posted April 30, 2011 Report Share Posted April 30, 2011 Our old MoPar reservoirs have a hole in the cap and are vented to the outside world:) That of course does not explain how moisture would get into a 2008 Taurus system:) I was just going to say that.... Not the best system to keep moisture out of the brake fluid. Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted April 30, 2011 Report Share Posted April 30, 2011 Sorry, I kinda just forgot what forum this is ! See, I really get into nitpicking. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted April 30, 2011 Report Share Posted April 30, 2011 Sometimes My 2008 Taurus makes a grinding sound when I back out in the morning and step on the brakes. I suspect the noise you hear has nothing to do with the brake fluid. I have owned several furd products with anti lock brakes. Every one has made strange noises and acted strangely the first time I hit the brakes after the vehicle has been sitting for a day or more espically if it rained while the vehicle was sitting idle. I always warn my wife to hang on if she is with me as the brakes will lock up for a split second the first time I hit the stop pedal. This first happened with a 1993 F-150 pickup in 1993. I consider it normal if anything about a furd is normal. Quote Link to comment Share on other sites More sharing options...
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