Brake fluid ?

[sean210]

My master cylinder is going bad and i bought a new one.

my father in law works at napa and he said that the computers there said to use dot4 brake fluid.

i was going to use dot3 but i wanted to make sure which one to use.

also is there such thing as dot4 brake fluid.

 

[benchwarmer]

There is such a thing as DOT4 fluid. DOT3 will be fine.

 

[tok]

been using dot 3 for years with no problems. i think it even says to use dot 3 on the cap.

 

[Who]

Dot3 and Dot4 are essentially the same except for the boiling point. Dot5 I believe has a silicone base to it and can sludge up in older brake systems. Take note that brake fluid loves water. Old brake fluid can have a high water content in it and boil at a lower temperature. Get plenty of dot 3 or 4 and flush or bleed the system trying to replace all the old fluid. Valvoline makes a brake fluid that says 3 & 4 right on the bottle. Buy plenty of it and flush the system out several times. Thats what I used and I had no issues.

 

[supradjza80]

If you drive your car at all aggressively i would highly recommend a DOT4 or DOT5.1(non silicone based ultra high temp fluid). A cheap and good DOT4 fluid is Valvoline Synpower fluid. Dry Boiling point of 502 F and wet boiling of 333 F. Its good stuff for 3$ a pint.