Brake Fluid DOT4 or 5.1?

[r1sc]

2012 X5M, what's the preferred fluid and why isn't this in the manual?

Plan to use my Motive power bleeder, any special considerations or is it just like any other car?

[omgboost]

I use pentosin dot 4 lv ony 35i. Change was very simple using the motive power bleeder. Although mine wouldn't hold pressure for an extended time

[racermp]

Do not use 5.1, it's ment for specific cars

Check the brake fluid cap on the car

[cbakking]

I just got brake flush done, they (dealer) used DOT4

[nlastovi]

Originally Posted by racermp

Do not use 5.1, it's ment for specific cars
Check the brake fluid cap on the car

DOT 5.1 (not DOT 5) is an upgrade from DOT3/4 and is fully compatible. It is less viscus (in other words, thinner) and has a higher boiling point. All else equal it would be considered somewhat superior.

[Kraftwerk AG]

Originally Posted by nlastovi

DOT 5.1 (not DOT 5) is an upgrade from DOT3/4 and is fully compatible. It is less viscus (in other words, thinner) and has a higher boiling point. All else equal it would be considered somewhat superior.

Correct!

[racermp]

Sorry my bad, I was thinking 5. Hehe

[nlastovi]

Originally Posted by DeeO

Correct!

My understanding is that 5.1 was originally developed (and, IMHO, poorly named) in association with antilock braking systems. Having a somewhat less viscous fluid would make it a bit easier to move during rapid on/off sequencing associated with ABS. That it has a higher boiling point is great too when subjected to extremes.

There are some DOT 3 and 4 fluids as well with much higher boiling points intended primarily for competition applications. Motul Rbf 660 Dot-4 for example has a dry boiling of 617°F and wet boiling point of 400°F.