what brake fluid type should I use?

[Grubester]

I have Mk 4 w/11.65" brakes: FFR standard brake items as part of the complete kit.

Wondering what brake fluid is recommended for these cars... Thanks!

[egchewy79]

DOT 3 or 4 should be fine.

really anything but Dot 5

[gbranham]

I used Dot 4.

Greg

[tnt_motorsports]

I would use what your other vehicles take so you don't have a unique fluid, unless of course that is DOT 5.

[edwardb]

I've used Valvoline DOT 3/4 Synthetic in all my builds. Standard parts store item and reasonably priced. No reason to get exotic unless a full-time track machine. Even then lots of opinions.

[OB6]

Walmart / Supertech DOT 3.

[BEAR-AvHistory]

Valvoline DOT 3/4

[BornWestUSA]

Dot 3 or 4, Dot 4 has a higher boiling point.

Best practice is to completely flush it every two years.

Brake fluid is hygroscopic, it absorbs water, that starts corrosion.... flushing it out increases the longevity of components.

[OB6]

Best practice is to completely flush it every two years.


This is more important than the brand of brake fluid you use, just like regular oil changes.

[JohnK]

One other thing to note is that the higher the boiling point, the more hygroscopic the brake fluid is. Some folks think that if Motul BF 600 (600 deg. F boiling point) is good, then RBF 700 must be better, but the reality is that even the RBF 600 is overkill, and the only thing that running RBF 700 will get you is more frequent fluid flushing.

[Grubester]

Well, good to know. So, where's the sweet spot for a car that is primarily a streetcar? I bleed the brakes today with a synthetic, Prestone, DOT 4.
For my use would DOT 3 have been thoroughly sufficient? I understand hygroscopicity, just not w.r.t. brake fluids.

[GoDadGo]

I too am running DOT-4 like many other forum members.

[tonywy]

Ford Motorcraft High-Performance DOT3. It has high wet and dry boiling points, a good compression factor, inexpensive, easy to get and better than your "parts store" fluids.

[JohnK]

Any good DOT 4 is more than sufficient for the street. You're never going to overheat the brakes to the point of worrying about boiling the fluid on the street. Use something from a name brand that's readily available and flush it every two years. For track I plan to run Motul RBF 600.

[OSU Cowboy]

I attended the build school in 2008. At that time, they recommended DOT-5, and that's what I used. I think the good news is that it doesn't absorb water, and that's a good thing for a vehicle that is driven on occasion.

Not sure what the negatives are for DOT-5 aside from the fact it can't be mixed with 3 or 4.

[Todd Baumann]

I attended the build school in 2008. At that time, they recommended DOT-5, and that's what I used. I think the good news is that it doesn't absorb water, and that's a good thing for a vehicle that is driven on occasion.

Not sure what the negatives are for DOT-5 aside from the fact it can't be mixed with 3 or 4.

OSU Cowboy

This is not what we recommend in the Build School, this is what we use because we tear our system completely apart every couple of weeks and it keeps from eating the paint away on everything. Otherwise we would be using Dot 3 or 4 also

Everyone please read your Wilwood instructions and use what is recommended

[rich grsc]

Agree with Todd, DON"T use Dot-5

[Jeff Kleiner]

Not sure what the negatives are for DOT-5 aside from the fact it can't be mixed with 3 or 4.

Well I’ll tell you what the negatives are and since it’s been a few years since I delivered this lecture I guess it’s time to do it again. Trust me on this---DO NOT USE DOT5. In a nutshell it is a silicone fluid and retains millions of tiny air bubbles making it compressible meaning you will never get a firm pedal. Additionally it is non-hygroscopic (does not mix with water) so any moisture will stay separated and since H2O is heavier than the silicone it will settle in the low points; i.e. calipers. Get the brakes hot, the water boils and you have no brakes! Todd clarified why they use DOT5 in the school car which makes perfect sense considering that it gets torn down monthly and is never driven any more than around the parking lot. If you don’t plan to do that with yours stick with glycol based DOT3, 4 or 5.1 fluid. OSU Cowboy, if you want to change over you need to push all of the 5 out of the system then flush it with a couple of quarts of denatured alcohol before refilling with proper glycol based fluid. After refilling you still need to push 2-3 quarts of that through. I had to go through this when a customer purchased an orphaned build then brought it me to complete and I discovered that it was filled with 5.

Jeff

[Takis31gk]

Any quality DOT 3 or 4 should be OK. If you're racing, consider the DOT 4.