Brake Fluid Moisture Absorption Rates

[pgtr]

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Hmmm, fluids have no compresibility...

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I was wondering when someone was going to come around mentioning that...

 

[9c1]

Annual or every two years (my preference) brake fluid flushes should also keep the bleeder screws free, if one re-lubricates them when flushing the fluid. When rebuilding the calipers or wheel cylinders most, if not all, of the fluid is changed. One would have to go out of their way (pinching the rubber hoses) to retain the fluid, at the risk of damaging the hoses internally.
All of life is a trade-off, but labman makes a good point. Brakes are not a place for the uninformed or untrained to learn a craft. On the other hand, brake fluid flushes should not be too difficult for anyone with reasonable mechanical skills.

 

[pgtr]

VaderSS: In regards to firmer pedal feel immediately after bleeding - Is it at all possible that there are small pockets of air that you are bleeding out when you change fluids? Bubbles? Perhaps small almost 'micro' bubbles? If you bleed w/ an assistant pumping the pedal and use a clear tube - you might notice this if you watch carefully...

thanks,

 

[DPMiller]

You guys gotta realise that attitudes towards servicing differ a lot each side of the Atlantic. In the US, as well as main dealers, you have individual "shops" for each area of competence- brakes, muffler, transmission. We don't have these so called specialists, we have main dealers , independant general mechanics, and tyre/ muffler/ brake/ shock/ oil change qwik- lube type places. I believe our service schedules aim at more preventative maintenance-
No- one in Europe would have drums or discs turned, few rotate tyres, and unless you're looking at a classic or obsolete vehicle, brake parts (calipers, cylinders) are replaced, not rebuilt- OK sometimes exchanged for factory rebuilt...
So a regular fluid change DOES help the longevity of the system. No sense having your brakes rusting from the inside out! Plus safety is an issue- our speed limits are higher, so more heat is generated in a panic brake.

Remember, leaving fluid in the system for many years then doing a pedal to the floor flush/ bleed is a great way to shred the seals in the m/cyl as they pass over the rusty end of the bore you don't normally use...

 

[VaderSS]

quote:

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VaderSS: In regards to firmer pedal feel immediately after bleeding - Is it at all possible that there are small pockets of air that you are bleeding out when you change fluids? Bubbles?

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I use a clear tube going into a glass jar so I can watch the fluid come out. No bubbles, just darker fluid turning into lighter fluid as the new fluid gets out to the corners.

Just so no-one thinks this is something I just stumbled onto or something, I've been doing my own brakes and my family's brakes for 15 years now. I usually use new or factory rebuild parts, when parts are needed. I've rebuilt a few parts, but often, the factory rebuilt is almost as cheap as the kit, cheaper if you factor your labor in, and I like to keep it simple.