After six years and 4000 miles I finally got to changing the brake fluid ....this is what my DOT 4 looks like. What was I thinking?
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Re: Yes, we all know we should but ...
Wow, where the heck do you live? I have brake fluid that has been in the system for 10 years that looks like new.Big Tanks In the High Mountains of New Mexico -
Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: Yes, we all know we should but ...
Darkening of the fluid doesn't necessarily mean it's "bad" in terms of moisture or other contaminants, which is the biggest danger to the hydraulic components. I believe the darkening is due to two issues. The first is tiny wear particles from the internal rubber parts, and a second may be oxidation due to heat.
It's been a few years since I flushed the system in my '91 MR2, but the fluid looks new, possibly because the m/c is located in the front compartment, so it's not subject to engine heat.
Wear particles, if not flushed out will eventually form a sludge at the bottom of the m/c reservoir, which can end up plugging the compensating port that can lead to loss of pedal height. They can also cause sticky pistons in wheel cylinders and calipers.
You can buy test strips that you dip in the fluid and color change will tell you if there is excess absorbed moisture or other contaminants, but it's not a bad idea to just skip that and change when the fluid darkens noticeably, especially if it's a car that you plan on keeping indefinitely.
Back when my '88 MBZ and '91 MR2 were daily drivers I changed the fluid (DOT 4) every two years. Now that I am down to driving each only about 500 miles per year I'm flushing the brake/clutch fluid systems (and doing coolant changes) every five years. The only brake/clutch work I've done those cars is fluid flushes and pad changes. I've never had to replace or overhaul a hydraulic component.
No cooling system issues with them either other than pumps. In fact, I have yet to ever own a new car that got more than 50K out of the original coolant pump, but I have a shot as the MR2 now has about 48K, so maybe it will make it past 50, but it will take me a few more years to get there.
DukeComment
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Re: Yes, we all know we should but ...
Gents:
ALL new system in 2010,... Is this the result of me not flushing the new calipers?? The fluid in the MC seemed OK,... and I remember flushing the new steel lines,....but not the calipers.Comment
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Re: Yes, we all know we should but ...
Mike,
You have to drive the car to get it to look like that! HA HAComment
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Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: Yes, we all know we should but ...
The colour of brake fluid is not a good indicator of it's condition. Clear fluid can be heavily contaminated, dark cloudy fluid might actually be OK. You mentioned that the sample in the pic is from a caliper. That's the least likely spot for water or other contaminants to enter, so possibly what you're seeing is some carbon black being released from a seal.
I'd just flush the system and not worry.Comment
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Re: Yes, we all know we should but ...
If you installed "new" calipers, then they would have been flushed in the process of filling/bleeding the system. It's probably break-in wear particles from the new rubber components that darkened the fluid. Chances are color change will be slower over the next period.
DukeComment
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Re: Yes, we all know we should but ...
Duke
Thank you for the good advice. I'm going to check the fluid at the calipers again next year... The calipers (new Lonestar castings) came as a "kit" with pads, rubber brake hoses, and the rear trailing arm lines. Never thought about the rubber hoses until now........much of the rubber products in the restoration world don't seem to have the quality. This might be another case of "live and learn".Comment
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Re: Yes, we all know we should but ...
DOT 5 is your friend. I've had it in my 67 for years with no problems whatsoeverComment
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