It is usually recommended that brake fluid is changed every 2 or 3 years. When my car is serviced by the main dealer, they check the fluid boiling point. The latest service on my 3 year old Focus says the boiling point is 196 deg C, with a minimum allowed of 155 Deg C.
So is there any need to change the fluid every 3 years if the boiling point is OK?
Many thanks,
Pete Mansell
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Pete,
for safety's sake, just do it.
a few litres of fluid, and a few hours one afternoon.
ask an experienced bloke to show you how it's done
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Pete,
Ian is right given the small cost.
Also I'm not sure but as you test at the filling point could the fluid be at a lower spec at the wheel ends of the system.
If you leave this for too long when it is done the bleed nipples might be seized and snap, that could cost £120 for a caliper.
When I bleed systems the fluid at the rear wheel cylinder ends is usually very dirty, I like to see this flushed out as well.
David
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David and Ian are both right. Do it. Brake fluid is hygroscopic, that is it absorbs water. That's what lowers the boiling point. However, the water corrodes the insides of the system leading to early failure of whel cylinders etc. If you have ABS, just price up a new unit and then decide if you will risk water in the system!
Mike
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The Hydra (Greek Mythology)was a many headed water snake. I thought Mike had made a mistake but just in case I got egg on my face, I looked it up and hyGroscopic is correct. You live and learn.
The other way to deal with brake fluid is never to touch it at all. I've had loads of cars and only had seized pistons twice in 30 years, the youngest car being 7 years old. (Also had one brake failure due to boiling, but that was a one off coming down the alps in a very old Triumph 2000.) If your Ford dealer says the boiling point is OK, that must mean very little moisture has got in. Another reason to leave it. Some cars are a bitch to bleed, eg the Audi 100. Don't know about the Focus, but if you do it, make sure no air gets in just in case.
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As well as the above, water uptake can increase fluid compressibility giving you a spongy pedal
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Pumping new fluid in at the top while releasing it at the wheel cylinder is not bleeding, as there is no air to bleed. So the potential difficulty of bleeding out all the air does not really arise. Simply pump out fluid at each nipple in turn until it runs clear.
I agree with the other posters - a wise precaution, and the regular freeing of the bleed nipples pays off. When you round off a seized up one, or snap it off, you certainly curse the false economy of "leave and forget".
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