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Someone educate me brake fluid change frequency.

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Old 03-29-2016, 01:15 PM
  #16  
Fishey
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Originally Posted by Kevinmacd
First off no one has said silcone based brake fluid is a cure all. The discussion was about moisture. Secondly mineral oil based synthetic is totally different than silicone based. Not advocating mineral oil based brake fluid is compatible, just pointing out the characteristics.
Staying with a high qualty dot4 per Porsche is the way to go for all round performance.
Synthetic fluids absorb water
Old 03-29-2016, 04:19 PM
  #17  
Kevinmacd
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Originally Posted by Fishey
Synthetic fluids absorb water
Wrong only glycol based synthetic brake fluid absorbs water, there are other base synthetics other than glycol based that do not, one being silicone and the other being mineral oil based. So its a wrong statement to say synthetic fluids absorb water.
Old 03-30-2016, 01:51 AM
  #18  
mcbit
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An extract from Stoptech.com explaining that Dot 4 fluids need to be changed more regularly as they absorb water more readily.

DOT 4 fluids are also glycol ether based, but have a measure of borate esters added for improved properties including increased dry and wet boiling points. A seldom talked about characteristic is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. By FMVSS116 standards, DOT 4 fluids must have a minimum dry boiling point of 446°F and a minimum wet boiling point of 311°F.

DOT 4 is the grade applicable to most race engineered brake fluid in the world today, especially with regard to viscosity limit. Note that although the DOT 4 designation has a minimum dry and wet boiling point, a DOT 4 racing brake fluid may have a dry boiling point over 600F. Its viscosity is challenged, however, to be under the viscosity limit of 1,800 mm2/sec. Some claimed racing brake fluids exceed this important limit. Caution should be exercised if these fluids are used in race cars with ABS systems. This does not mean that DOT 4 fluids are necessarily better than DOT 3 fluids. Remember, the boiling points listed are minimums. There are certain DOT 3 fluids with higher boiling points than some DOT 4 fluids. The real differentiating factor is that DOT 4 fluid should be changed more often than a DOT 3 fluid, because of the effects and rates of water absorption.
In general Dot 3, 4 and 5.1 are glycol based whilst Dot 5 is silicon based.
Old 04-03-2016, 06:39 AM
  #19  
SteveMFr
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Originally Posted by Kevinmacd
First off no one has said silcone based brake fluid is a cure all. The discussion was about moisture. Secondly mineral oil based synthetic is totally different than silicone based. Not advocating mineral oil based brake fluid is compatible, just pointing out the characteristics
That is seriously NOT the way your posts read. You touted all sorts of positives on silicone brake fluids while mentioning only one negative - compressibility. Why bother if silicone based brake fluid is not an option worth considering?

A Prius gets better mileage than a 996tt - but nobody here bothers discussing this because it's irrelevant.
Old 04-03-2016, 06:14 PM
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5ive0
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Originally Posted by SteveMFr
A Prius gets better mileage than a 996tt - but nobody here bothers discussing this because it's irrelevant.
Technically, a Prius full throttle around a track being followed by a 996tt will probably get worse mileage than our cars....since you brought it up
Old 04-04-2016, 09:31 PM
  #21  
Kevinmacd
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Originally Posted by SteveMFr
That is seriously NOT the way your posts read. You touted all sorts of positives on silicone brake fluids while mentioning only one negative - compressibility. Why bother if silicone based brake fluid is not an option worth considering?

A Prius gets better mileage than a 996tt - but nobody here bothers discussing this because it's irrelevant.
Its exactly what i have said all along. I also mentioned mineral oil base but then I guess you didnt comprehend!
Old 04-05-2016, 09:19 AM
  #22  
SteveMFr
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I just went back and read your posts again. TBH, I still don't "comprehend".

Last edited by SteveMFr; 04-05-2016 at 10:00 AM.
Old 04-05-2016, 12:34 PM
  #23  
Kevinmacd
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Originally Posted by SteveMFr
I just went back and read your posts again. TBH, I still don't "comprehend".
Not my issue, thanks!
Old 04-05-2016, 08:28 PM
  #24  
SteveMFr
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Actually it is. But you seem happy, so carry on...
Old 04-05-2016, 09:34 PM
  #25  
Alan A
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You all know you can't use dot 5 with abs right?
Went through this with the toy when the builder thought he'd save on possible paint damage by using it.

Purging the ABS back to 4 (in my case) was such a gigantic pain that it's etched in my memory.

There's a picture of what happens here:

http://www.motorweek.org/features/go...fluids_and_abs

Last edited by Alan A; 04-05-2016 at 09:37 PM. Reason: Add citation
Old 04-06-2016, 02:20 AM
  #26  
993GT
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Deal with it frequently, change the fluid....
Old 04-06-2016, 12:22 PM
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Kevinmacd
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Originally Posted by SteveMFr
Actually it is. But you seem happy, so carry on...
Not really, keep trying though! You seem to be the only one trying to raise a comprehension issue!
Old 04-06-2016, 06:06 PM
  #28  
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I win.



LOL
Old 04-07-2016, 11:39 AM
  #29  
"02996ttx50
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iirc I just completed approx 5 years without swapping out my fluid. waited (inadvertently! of course ) until all 4 rotors were "due". call it forgetfulness or negligence. (!?!) either way, no negative long term effect, of which i was made aware. STILL stop on a quarter, and NO!! brakes= squeal!

mintex ( oem replacement ) ( cheep as ^^^^^!! ) x by ATE ( read: CHEEP! didn;'t even spring for sebros! slotted, just drilled! ) oe replacement rotors. i Must be getting old(er?! ) as 8/10 times I don't feel i'm sacrificing quality for performance. but then i don't suppose i'm entering corners as hotly i once did., gottta factor that in i suppose!
Old 04-08-2016, 05:50 PM
  #30  
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You will not be able to judge the negative long term effect of the corrosion of internal brake components due to the accumulation of water in the brake fluid just yet. This will happen in another 10 years or so when the cylinders begin to fail, or the brake lines begin to rust through.

Dan


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