Brake fluid - what type are you using, and where to get it??
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Good grief, I remember those now!! We used to sell them when I was a Saturday boy at a car accessory shop!! and that was a few years ago 8)
Gavin Chisholm - 414ci W2 Stroker SmallBlock Panther Pink '71 Challenger convertible - in bits
Car progress can be viewed here
Car progress can be viewed here
Hmm, you boys are worrying me now, When I looked into silicone fluid some years ago there was no mention of spongy pedals or water sitting at the lowest point! The only thing bad anyone was saying about it was the cost, it seems to be widely used in circuit racing and in murdercycles and apparently the NYPD only use silicone fluid in their police cars! Wilwood, BTW state "do not use silicone brake fluid" in their brake kit instructions but give no reason, telling you instead to use thier own brand fliud! I figured this was just a sales pitch... Richard Eherenberg once wrote an article about it stating where you could buy it from for sensible money, and once the cost issue was out of the way why would you want to use anything else? I'll have to do a bit more research into this one.....
“It’s good enough for Nancy”
Blue, yeah I've been through the same thoughts. There are plenty of good resources on the Web, I'll post a couple of good ones at the bottom of this.
From memory, here are the main points I discovered.
Silicone fluid has a higher boiling point, hence some race cars etc use it. Also the military in the US use it, primarily because their vehicles sit there for long periods without use, and conventional fluid loves absorbing water, which lowers the boiling point of the fluid (that's why polyglycol fluids have a dry and wet boiling point, silicone only a dry).
Silicone definitely does entrain air more easily, hence some reports of spongy pedals etc. Issues with seals only apply to natural rubber, shouldn't be a problem for any of us. Contrary to popular belief, you can mix any type of fluid (it's a condition of the DOT specification), but if you do that you'll end up with the worst of both worlds - but your brakes will still work. Actually silicone fluid would just be at one end of the pipe and the conventional fluid at the other - you can 'mix' them, but they actually won't mix together! (but the brakes work!).
An open question for me is the collected water sitting at the lowest point of the system (which you would have thought would be a concern to the US army!). That does seem to be a common theme, but I'm guessing that a) you get much less water than with normal fluid (albeit in one place rather than absorbed throughout), and b) if you bleed your brakes every year (or two) you shouldn't have any trouble. Maybe this idea that silicone fluid 'is for life' has led to people not bleeding their brakes anymore, which then causes issues.
DOT 5.1 is a conventional (polyglycol) fluid (with all the pros and cons of that), but with the boiling point of silicone fluid. Could be a good fluid to use.
I too have read E-Bergs praise of silicone, one factor that definitely got me thinking about using it. The only other thing I've noticed is that the majority of technical articles are not heavily in favour of silicone, but the majority of people like us (muscle car owners) who use it and report on their experiences are very positive. I'd say around 5:1 in favour or higher. most of the negative experiences are do do with the spongy feel and not being able to get a hard pedal (though not everyone has that problem)
Tough to say what conclusions to draw.....In a properly maintained brake system I don't think safety is a deciding factor. They are all safe and all work. Price is clearly an issue for silicone (and maybe 5.1?) so if there is no real benefit why use it. The paint resistance though is very useful, though as long as you don't get unoticed leaks conventional fluid is easy to wipe off as people have mentioned.
If you've already silicone it I certainly wouldn't change it. I'm still not sure but will probably go with DOT 4 or 5.1
Such decisions!
From memory, here are the main points I discovered.
Silicone fluid has a higher boiling point, hence some race cars etc use it. Also the military in the US use it, primarily because their vehicles sit there for long periods without use, and conventional fluid loves absorbing water, which lowers the boiling point of the fluid (that's why polyglycol fluids have a dry and wet boiling point, silicone only a dry).
Silicone definitely does entrain air more easily, hence some reports of spongy pedals etc. Issues with seals only apply to natural rubber, shouldn't be a problem for any of us. Contrary to popular belief, you can mix any type of fluid (it's a condition of the DOT specification), but if you do that you'll end up with the worst of both worlds - but your brakes will still work. Actually silicone fluid would just be at one end of the pipe and the conventional fluid at the other - you can 'mix' them, but they actually won't mix together! (but the brakes work!).
An open question for me is the collected water sitting at the lowest point of the system (which you would have thought would be a concern to the US army!). That does seem to be a common theme, but I'm guessing that a) you get much less water than with normal fluid (albeit in one place rather than absorbed throughout), and b) if you bleed your brakes every year (or two) you shouldn't have any trouble. Maybe this idea that silicone fluid 'is for life' has led to people not bleeding their brakes anymore, which then causes issues.
DOT 5.1 is a conventional (polyglycol) fluid (with all the pros and cons of that), but with the boiling point of silicone fluid. Could be a good fluid to use.
I too have read E-Bergs praise of silicone, one factor that definitely got me thinking about using it. The only other thing I've noticed is that the majority of technical articles are not heavily in favour of silicone, but the majority of people like us (muscle car owners) who use it and report on their experiences are very positive. I'd say around 5:1 in favour or higher. most of the negative experiences are do do with the spongy feel and not being able to get a hard pedal (though not everyone has that problem)
Tough to say what conclusions to draw.....In a properly maintained brake system I don't think safety is a deciding factor. They are all safe and all work. Price is clearly an issue for silicone (and maybe 5.1?) so if there is no real benefit why use it. The paint resistance though is very useful, though as long as you don't get unoticed leaks conventional fluid is easy to wipe off as people have mentioned.
If you've already silicone it I certainly wouldn't change it. I'm still not sure but will probably go with DOT 4 or 5.1
Such decisions!
Gavin Chisholm - 414ci W2 Stroker SmallBlock Panther Pink '71 Challenger convertible - in bits
Car progress can be viewed here
Car progress can be viewed here
Whoops, forgot the links. there are plenty more, these I found amongst the better and seem to be representative of the more 'informed' articles, as far as I could tell.
Not all accurate but mostly, plus some user experience too
http://www.stoptech.com/whitepapers/brakefluid1a.htm
http://www.imperialclub.com/Repair/Brak ... efluid.htm
Not all accurate but mostly, plus some user experience too
http://www.stoptech.com/whitepapers/brakefluid1a.htm
http://www.imperialclub.com/Repair/Brak ... efluid.htm
Gavin Chisholm - 414ci W2 Stroker SmallBlock Panther Pink '71 Challenger convertible - in bits
Car progress can be viewed here
Car progress can be viewed here
Some good reading there Gav! I feel Much better informed now than I was about this stuff. I will keep the silicone fluid in there for now and if I experience any of the symptoms mentioned I can alway's change it then. Sounds like a yearly brake bleed needs to be added to my service schedule to avoid the trapped water syndrome!
“It’s good enough for Nancy”
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