Can you mix brands of DOT 4 brake fluid?

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Originally Posted By: enochian
Can you top off with a different brand of DOT 4 brake fluid?


Yep, you can mix.
 
Not always - there are a few different types of DOT4 fluid and it is important they are not mixed if you want to retain the same properties. You need to find out which type of DOT4 is required by the OEM.

1) Super DOT4

2) DOT4 Low Viscosity (if you mix this with "regular" DOT4, you will lose the low temp properties that DOT4 LV is used for)

3) Regular DOT4
 
Whats the difference between Super and regular?

Do you know what type BMW brake fluid is?
 
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Originally Posted By: enochian
Whats the difference between Super and regular?

Do you know what type BMW brake fluid is?


Super DOT4 has higher boiling points than regular DOT4. But Super DOT4 should not be used in applications calling for DOT4LV.

Most BMW vehicles that are 2002 or newer require DOT4LV.
 
Originally Posted By: The Critic
Originally Posted By: enochian
Whats the difference between Super and regular?

Do you know what type BMW brake fluid is?


Super DOT4 has higher boiling points than regular DOT4. But Super DOT4 should not be used in applications calling for DOT4LV.

Most BMW vehicles that are 2002 or newer require DOT4LV.


While this is a valid point.


In most cases, YES you can mix any DOT4 fluid. Just stay away from DOT5

High-performance cars/driver/driving are normally maintained at a higher level which required that. Most my friends that do HDPE, auto-x and drift events all look for highest boiling points because they have cooked their pads and fluids on the tracks. But generally speaking, no one should have issues on the STREET.

I wouldn't worry about it if this is a Daily driving car. Its better to have fresh fluid then 2+ year old fluid. Oddly enough, i've worked on mid 90's car with fluid blacker than oil, i assume its factory filled and its still working, i would assume all the moisture it absorbed the boiling point has to be like 150degrees, compared to DOT4 which is like 350.
 
Originally Posted By: enochian
Which brake fluid do you recommend for 2008 BMW?

Besides BMW.

Pentosin DOT4LV or ATE SL6. I think the Pentosin one should be available from Autozone for about $20/L.
 
Yes you can mix any DOT4 with no problems.

If you can find it, Castrol DOT 4 is great stuff. Absorbs moisture more slowly, and also higher boiling points than the DOT 4 minimum. Amazon has it at a great price if you buy in bulk.

Mag 1 DOT 4 is also a good value.

You can also use NON-silicone DOT 5.1, which is similar to DOT 4 LV but slightly better (higher boiling points and lower visc) (note that 5.1 is NOT the same thing as silicone DOT 5)

eBay has six quarts of Ravenol DOT 5.1 for $45. It seems to come in metal cans, making it safer to buy in bulk. This is probably what I'd use.

Amazon used to have Wagner Severe Duty DOT 5.1 at a good price, but their stock is inconsistent. I have a bottle of this right now.
 
While there are some slight differences, I was at one of the brake fluid plants a few years ago and they had about 3 dozen brands of packaging and just filled the same product in all.

I bought the Pentosin product last week on Amazon for my Daughter's Odessey
 
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