I wanted to know if it is ok to use DOT4 brake fluid in a DD, and if Dot 4 is ok to use in all kinds of weather, including winter driving, and how often I should look at flushing it?

I am planning on a 2 track days and looking at a couple upgrades around the brakes, pads and stainless lines.

In reading old threads, it looks like a lot of people liked the ATE Super blue, but that doesnt appear to be available in the US anymore. So ATE type 200 and Motul RBF 600 look to be the next available choices. Any recommendations between these 2.


Thanks.

 

Yes it's OK. It's not OK to mix with 3, so make sure to flush properly.

 

It is ok to use Dot 4 for daily driver since the only difference really with Dot 3 is the boiling point. Under normal use, you should not feel any difference. Under heavy use, the Dot 4 will get most of its effectiveness.

The enemy of glycol-based brake fluid (Dot 3 and Dot 4) is humidity as water get mixed with the fluid and lower its boiling point. For DD, you don't have to flush brake fluid unless you feel unusual softness or resistance in the brake pedal. For the track, boiling point is very important to keep the effectiveness of the brakes under heavy use. I would flush the old Dot 3 a few days before the track to make sure no water get mixed with the new Dot 4.

 

Thank you!

 

For fluid recommendations:

Motul RBF600 is good for an occasional track day - I've used it in the past and lots of folks use it regularly. It's dry boiling point is very high, wet is pretty good.

Castrol SRF is the best - it's more expensive, but it's wet boiling point is untouched by any other fluid. I did about 20 track days (instructor group) on mine last season and just flushed it yesterday in prep for 2016 season. Fluid appeared essentially brand new, and I only get the occasional bubble at brake-intense tracks, like Watkins Glen. Highly recommend it!

 

Thanks. I think I'll try the Motul and if I start doing more track dates move up to the Castrol.