Brake fluid question

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Pennsylbammyvania
Originally Posted By: Gimpy1
USE Castrol SRF. The per litre price will give you a heart attack.
I am considering it for my first changeout despite it's 'liquid gold' status/co$t. (Hard to argue with a 518*F wet boiling point!) The manual does spec a Low Viscosity fluid though, IF that has any bearing on my choices. shrug
 
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Pennsylbammyvania
Originally Posted By: artificialist
I use DOT4 on non-abs brakes and I use DOT4 low viscosity on ABS brakes. That is because DOT4 is cheaper than DOT4 low viscosity, and DOT4 low viscosity mostly exists so the ABS module can react faster. Typically I use Valvoline DOT4 and I use Pentosin DOT4LV low viscosity.
The Bosch LV stuff (on the shelf at Auto Zones) has slightly better wet and dry boiling points than the Pentosin LV.
 
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Taiwan
Originally Posted By: dailydriver
Originally Posted By: Gimpy1
USE Castrol SRF. The per litre price will give you a heart attack.
I am considering it for my first changeout despite it's 'liquid gold' status/co$t. (Hard to argue with a 518*F wet boiling point!) The manual does spec a Low Viscosity fluid though, IF that has any bearing on my choices. shrug
I think I could manage to "argue with a 518*F wet boiling point". Whatever that is in meaningful units (can't be bothered to convert it to centigrade), I'm not very interested in wet boiling point, because I don't intend to use wet brake fluid. Even if it works fine as brake fluid, I'm unsure that its corrosion resistance hasn't been compromised. With a quick, cheap change of DOT3 I get rid of the water and wet boiling point becomes irrelevent. High performance or track use might be another matter, but that not relevent to me either.
 
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Taiwan
Originally Posted By: mightymousetech
Originally Posted By: Marco620
Dot 3 lasts longer,Dot4 has better performance but needs changing more often.
That's not true. One of the main benefits of DOT4 is that it has a higher wet boiling point.
The two statements are not incompatible, so "That's not true" is not appropriate. If "lasts longer" is defined as "having a higher wet boiling point after 2 years" then "That's not true" is OK, but since "Last longer" is not defined, it isn't. "Lasts longer" COULD be defined by rate of water absorption, but there is no information about this on the graph, which only refers to a single time point. Moreover, as drawn, the graph implies that ALL the fluids have EXACTLY the same amount of water in them (about 3.6%) after 2 years service. This seems rather unlikely, and tends to undermine its credibility a bit.
 
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Second one says DOT3 is higher viscosity. That'd presumably be better (for a non-ABS system at least) since it seems likely to reduce wear. Also says ""*Some manufacturers sell brake fluid with much higher boiling points. These fluids are intended for use in race vehicles only and should not be used in daily drivers or street vehicles.** Doesn't say why they "should not be used in daily drivers or street vehicles.", but perhaps they, too, could "argue with a 518*F wet boiling point". Neither of them say anything about relative water absorption.
 
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Taiwan
Originally Posted By: Dylan1303
This aritacle says dot 4 is less hydroscopic. Witch is why i wanted to use it in the first place. https://www.google.com/amp/s/www.speedwa...fications/28676
This could be true. Its the reverse of my recollection of what I'd read, but I don't have the source and might be mis-remembering. However, there's enough technically illiterate bollocks in that article that I'd want independant confirmation of anything it said before I acted on it. For example "If you look at the chemistry behind most brake fluid, it comes from the combination of various types of glycols, which are basically a mixture of non-petroleum and other alcohol-based fluids. After a mixing process, the chemical name gets shortened to “polyglycol”." Tosh "But there are a few draw backs to silicon-based fluids, they expand more when compressed...." Expand more when compressed doesn't make any sense.
 
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Originally Posted By: Ducked
Originally Posted By: mightymousetech
Originally Posted By: Marco620
Dot 3 lasts longer,Dot4 has better performance but needs changing more often.
That's not true. One of the main benefits of DOT4 is that it has a higher wet boiling point.
The two statements are not incompatible, so "That's not true" is not appropriate. If "lasts longer" is defined as "having a higher wet boiling point after 2 years" then "That's not true" is OK, but since "Last longer" is not defined, it isn't. "Lasts longer" COULD be defined by rate of water absorption, but there is no information about this on the graph, which only refers to a single time point. Moreover, as drawn, the graph implies that ALL the fluids have EXACTLY the same amount of water in them (about 3.6%) after 2 years service. This seems rather unlikely, and tends to undermine its credibility a bit.
What this actually showing, probably, is simply the wet boiling point, which IIRC is DEFINED at 3.7% water. The "after 2 years service" thing, then, seems to be pure invention.
 
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Florida
Originally Posted By: dailydriver
Originally Posted By: artificialist
I use DOT4 on non-abs brakes and I use DOT4 low viscosity on ABS brakes. That is because DOT4 is cheaper than DOT4 low viscosity, and DOT4 low viscosity mostly exists so the ABS module can react faster. Typically I use Valvoline DOT4 and I use Pentosin DOT4LV low viscosity.
The Bosch LV stuff (on the shelf at Auto Zones) has slightly better wet and dry boiling points than the Pentosin LV.
That is great news. I never thought I would see any DOT4LV at Autozone. I can buy that and get Duralast brake pads at the same time, that is very convenient.
 
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South Carolina
I think you are over thinking it :o) Use the recommended fluid in the owners manual and let it rest. Here is why you should not over think it and listen to your owners manual = "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" All you want to know about brake fluid - Click
 
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Originally Posted By: alarmguy
I think you are over thinking it :o)
I think he's been misled by some bollocks on the internyet, of which there is no shortage. I wouldnt call that "over thinking it"
Originally Posted By: alarmguy
I've noticed that the China Petroleum Corporation DOT3 that I use comes in a plastic bottle. whereas the DOT4 stuff comes in a metal bottle. I've wondered if this was due to greater vulnerability to water, which that article seems to confirm.
 
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Pennsylbammyvania
Originally Posted By: Ducked
High performance or track use might be another matter, but that not relevant to me either.
THIS IS a factor to me, as open track use will be in this car's future, and the small, sliding caliper brakes need all of the help they can get to resist heat induced boiling/aeration and fade, especially with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track. Whether or not the SRF is really too viscous to allow for proper ABS function, I will have to determine before use. At least until I can afford an aftermarket, AP Racing multi-piston, fixed caliper setup. wink
 
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Originally Posted By: dailydriver
.......especially. with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track.
They make sticky tyres in Scotland? Surprised. Most Scots would want tyres to last longer than they typically do. We like to get our money's worth. I've thought of water cooling the calipers, (which would be free). I don't generally drive fast but there are a lot of mountain roads here and I coast a lot. OTOH I dont get out enough to justify it, so it'll probably never get to the top of the to do list. I'd guess thats probably disallowed by track rules.
 
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Originally Posted By: Ducked
Originally Posted By: dailydriver
.......especially. with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track.
They make sticky tyres in Scotland? Surprised. Most Scots would want tyres to last longer than they typically do. We like to get our money's worth. I've thought of water cooling the calipers, (which would be free). I don't generally drive fast but there are a lot of mountain roads here and I coast a lot. OTOH I dont get out enough to justify it, so it'll probably never get to the top of the to do list. I'd guess thats probably disallowed by track rules.
So I guess that your avatar location is some kind of an (inside) joke? shrug (and yup, MINE IS {an inside joke}) THAT'S what I was going by, as how else would I know, clairvoyance? LOL
 
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Cajun Country, La.
I usually buy almost EVERYTHING automotive at WM (fluids, oil, oil filters, etc.). But, when it comes to BF I like to find the lowest priced and WM wasn't it the last 2 times. One BF flush was from NAPA and another from AZ. NAPA was house brand, AZ was Prestone.
 
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Originally Posted By: dailydriver
Originally Posted By: Ducked
Originally Posted By: dailydriver
.......especially. with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track.
They make sticky tyres in Scotland? Surprised. Most Scots would want tyres to last longer than they typically do. We like to get our money's worth. I've thought of water cooling the calipers, (which would be free). I don't generally drive fast but there are a lot of mountain roads here and I coast a lot. OTOH I dont get out enough to justify it, so it'll probably never get to the top of the to do list. I'd guess thats probably disallowed by track rules.
So I guess that your avatar location is some kind of an (inside) joke? shrug (and yup, MINE IS {an inside joke}) THAT'S what I was going by, as how else would I know, clairvoyance? LOL
To quote Eccles (British 50's thing, don't worry about it) "Everybody has to be somewhere." Doesn't necessarily mean that's where you started. Or have nationality/citizenship. One possible clue would be use of the word "bollocks". Very few Taiwanese, however fluent in English, are likely to do that.
 
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Illinois
Originally Posted By: dailydriver
Originally Posted By: Ducked
High performance or track use might be another matter, but that not relevant to me either.
THIS IS a factor to me, as open track use will be in this car's future, and the small, sliding caliper brakes need all of the help they can get to resist heat induced boiling/aeration and fade, especially with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track. Whether or not the SRF is really too viscous to allow for proper ABS function, I will have to determine before use. And another vote for the Valvoline BF. At least until I can afford an aftermarket, AP Racing multi-piston, fixed caliper setup. wink
If you track the car it's always best to bleed the brakes before every event.
 
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Originally Posted By: Ducked
Originally Posted By: dailydriver
Originally Posted By: Ducked
Originally Posted By: dailydriver
.......especially. with sticky tires (YOUR country's Federal RS-RRs, BTW). I also will add ducting to the rotors before going out on track.
They make sticky tyres in Scotland? Surprised. Most Scots would want tyres to last longer than they typically do. We like to get our money's worth. I've thought of water cooling the calipers, (which would be free). I don't generally drive fast but there are a lot of mountain roads here and I coast a lot. OTOH I dont get out enough to justify it, so it'll probably never get to the top of the to do list. I'd guess thats probably disallowed by track rules.
So I guess that your avatar location is some kind of an (inside) joke? shrug (and yup, MINE IS {an inside joke}) THAT'S what I was going by, as how else would I know, clairvoyance? LOL
To quote Eccles (British 50's thing, don't worry about it) "Everybody has to be somewhere." Doesn't necessarily mean that's where you started. Or have nationality/citizenship. One possible clue would be use of the word "bollocks". Very few Taiwanese, however fluent in English, are likely to do that.
Yes, and I was kind of taking for granted that you were an EX-patriot British Isles citizen, transplanted into a new land (which you may or may not identify as "your own"). wink (Sort of like the many Brits still living in Hong Kong.)
 
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Originally Posted By: dailydriver
Yes, and I was kind of taking for granted that you were an EX-patriot British Isles citizen, transplanted into a new land (which you may or may not identify as "your own"). wink (Sort of like the many Brits still living in Hong Kong.)
Dunno if I'd count myself a patriot. Someone said patriotism was the last refuge of the scoundrel, but maybe I've found another. Post brexit-bollocks, if I had been a patriot, maybe I'd now be an ex-patriot. As well as an expatriate, of course.
 
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