Hi, I have read that Dot 4 can be used in place of Dot 3 in most places (other car forums, etc.). Is Dot 4 good for the Savage? I have 2006 s40.
Anyone tried Dot 4? Notice any difference?

I just looked up the difference in the two.

Dot 4 has a higher boiling point that Dot 3, and therefore is more heat resistant.

However Dot 4 absorbs moisture 20% faster than Dot 3.

It may not be desirable to do the switch if your bike is stored outside or in a damp environment.

If you switch to Dot 4 - don't neglect doing a brake fluid flush more often.

Avoid Dot 5 completely, as it is silicon based and doesn't mix with Dot 3 or Dot 4.

There also now exists Dot 5.1, which is compatible with Dot 3 and Dot 4, but has higher concentration of Borate Ester vs Glycol Ester than Dot 4, while Dot 3 is pure Glycol Ether.  The Borate Ester is what makes the hydraulic fluid more hygroscopic, and also have a higher boiling point.

Not sure why they didn't name it Dot 4.2 rather than 5.1, things were confusing enough.

I wouldn't expect to feel or see any difference, except in the price.

[quote author=42797463727E656378707D62110 link=1749612605/0#2 date=1749637950
Avoid Dot 5 completely, as it is silicon based and doesn't mix with Dot 3 or Dot 4. [/quote]

You can use DOT 5 but you have to flush with denatured alcohol first to make sure that no old fluid is left in the system. Make sure that the alcohol has evaporated (use an air nozzle to blow the lines clear and disassemble the master cylinder and caliper if needed)  before filling with DOT 5 then. I have done that on a few bikes and never had any issues doing it that way.