View Full Version : Trailer brake fluid

03-29-2009, 03:00 PM
I can't find what type of brake fluid to put in my trailer, there is no making on the cap. I'm guessing DOT 3. I have a 98 Outback and a boat mate trailer. The reason I want to change the fluid is that last summer my friend had a brake issue on the way to our holiday and $800. later he was on his way. Because his fluid was so contaminated the master cylinder was really rusty and dirty inside and the whole unit had to be replaced. I would rather give mine a good flush (the fluid looks clean under the cap) now so I don't have to take time from ski season to work on it.

03-29-2009, 07:52 PM
dot 3 is whats in it you can go to dot4 but you have it flush out all the 3 they don't mix

03-31-2009, 10:51 PM
Stick with DOT-3. It is the recommended fluid and readily available.

03-31-2009, 11:32 PM
Castrol LMA Dot 4!!!
Not as expensive as some of the other synthetics.
Why not go to a Better Fluid when $40K is behind you. Especially if you are only talking a dollar or two more a bottle???


04-27-2009, 06:06 PM
Use DOT 3. The boiling point is not as high but it draws in less moisture. DOT 4 will get contaminated quicker.