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Brake Fluid

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kyreb1862

kyreb1862

Jedi Knight
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Can I get some opinions on brake fluid. I got "Molly's" hydraulic system overhauled and went to the auto parts store to get fluid and frankly I came away a little overwhelmed by the variety of brake fluids. DOT3, DOT4, and about half a dozen different brands. The only brand I had heard mentioned was Castrol, which they didn't have. There was a Prestone brand in DOT3 and DOT4 is this a good brand? /ubbthreads/images/graemlins/confused.gif
 
Now that is a fine question. All is new but the master cyl on mine was rebuilt and has some fluid in it etc. Do I need to match that? What does not hurt paint?

Is there a link that discusses the options etc?
 
whew .. there are reams of info, opinions, advise on brake fluids on the web and the BCF. I would use a Dot 4 over Dot 3 because of the higher boiling point (both wet and dry boiling points). I would also seek out Castrol LMA (low moisture absorbtion) because it is (surprise!) formulated to absorb less moisture and is not overly expensive (like some racing brake fluids). Concerning mixing fluids .. it is best to completely clean out old fluid and unknown fluid types. Careful what you use to flush out the old stuff .. I would research this first to make sure you don't use something that deteriorates the seals. As for the question about harming paint, take a look at the thread in 'Car Care' called 'brake fluid experiment'. The Castrol LMA does not affect my cured paint but your milage may vary.

Cheers,
John
 
Well guess Castrol LMA it is then. Wonder if anyone else has anything to say.
 
DOT3 -Do not use on British cars it WILL rot your seals.
DOT4 (DOT4 should be flushed and replaced at 2-3 yr intervals)
-Castrol LMA -Low Moisture Absorbent, easy on seals
-Girling
DOT5 (Silicone) Doesn't absorb water, or remove paint. Can be a bit harder to get the air out, and may be more prone to boiling in heavy braking usage. Fantastic for long term storage -Good for 5+++ years.
 
I too could not find Castrol LMA when I did my brakes a couple years ago. What I used was Valvoline Synpower Synthetic Formula brake fluid - Exceeds Dot3 and Dot4.
Compatible with all DOT3 and DOT4 brake fluids. It doesn't claim to be DOT3 or 4, but claims it is a synthetic low moisture formula. Dry boiling point 480 F, wet boiling point 330 F. States on the bottle that it will damage car paint finishes.
 
BCF recommended the Castrol LMA so I put it in. Not a problem to report in brakes or clutch.
 
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Well guess Castrol LMA it is then. Wonder if anyone else has anything to say.

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Not really Jack ,except to say; go with the Castrol LMA.---Keoke-- /ubbthreads/images/graemlins/yesnod.gif
 
So go with the Castrol LMA if I can find it but, if not go with any brand of low moisture absorbing DOT4 brake fluid? /ubbthreads/images/graemlins/yesnod.gif
 
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DOT5 (Silicone) Doesn't absorb water, or remove paint. Can be a bit harder to get the air out, and may be more prone to boiling in heavy braking usage. Fantastic for long term storage -Good for 5+++ years.

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Jack, I use silicone in my systems. To get all the air out, I fill the empty system from the bottom up. This is how I fill aircraft braking systems.[In Aircraft, using only FAA approved fluids]. By using the bleed jets on the wheel cylinder and pumping the fluid up to the reservoir. It's actually a two person operation. Someone must watch the reservoir for incomming fluid. Some people say they have a soft peddle when using silicone. It's because they don't get all the air out. I wouldn't use it in a race car though, where brake fluid can reach a very high temperature in a short period of time. /ubbthreads/images/graemlins/cheers.gif PJ
 
/ubbthreads/images/graemlins/iagree.gif SRF is great stuff. At $70.00 (US) a liter it's a bit pricey, but it's all I run on the race cars. Castrol recommends replacing it at no longer than 18 month intervals.
LMA is still my choice for street use.
Jeff
 
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DOT3 -Do not use on British cars it WILL rot your seals.


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Perhaps true years ago, but hasn't been true in decades. As I understand it, D.O.T. 3 was not compatible with pure natural rubber seals once used in British brake systems, but if you've still got those seals in your car, you have other problems! ;-) D.O.T. 3 is compatible with all current-production seals. That said, D.O.T. 4 is still preferable, but if you're in a bind and need some fluid and D.O.T. 3 is all that's available, it's ok to use it.....
 
stick with Castrol LMA you can not go wrong with it go the extra mile and find it if u can't get it at the first try keep on trying
 
Both Moss and TRF list the Castrol LMA fluid.
 
DOT 3 is safe for British cars, although it's not great stuff. Absorbs moisture like crazy and rusts things from the inside, so you have to change it every couple of years. Castrol LMA is better at not absorbing moisture. DOT 5 is fine, but doesn't mix with DOT 3 or 4, so it needs to be dry to start with. I use DOT 5 because it is impervious to absorbing moisture, has a phenomenal boiling point (600 degrees F on the bottle I have), and doesn't harm paint. It is more expensive though; I paid about $30 for a quart from Moss.
 
No Castrol LMA here either but all the other brands.
 
If your current unit's fluid has a purple color to it, It is DOT 5 Silicone. The other types are compatable, but as suggested, try to clean all out to make it as same as possible.

I use Silicone in my TD and in my B. The TD sits around a lot more. I originally put it in nearly 20 years ago. I drain and refill every 4 to 5 years and have yet to replace one part of the system. Prior to using silicone, I had to rebuild the stuck wheel cylinders every year when I took the car out of storage.

I also put silicone in my B. It is a street car and I like the fact that my paint is not dissolving. I have not had any big problems in getting the brakes bled, I use a vacuum system and it works well at pulling out the air. Pedal is very hard and system works perfectly.

Negative on silicon is you have to work real hard to get it off any area of paint when you want to do any body work. Use a silicon removing solvent two to three times prior to doing any sanding. You will be lucky then if you don;t have fisheye.
 
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