69 cadillac de ville brake fluid

[1969cadillac]

hello - should i used dot 3 or dot 4 brake fluid in this old car ?

thanks, Murray Mules

[62droptop]

dot 3 fluid should be  what it calls for

most of my old british calls for dot 4
if i remember the dot 4 was a low moisture absorbing formula

here is difference found online

DOT 3
As the most common type of brake fluid, DOT 3 has a dry/wet boiling point of 401/284 degrees Fahrenheit. DOT 3 must be used from a capped container to keep out moisture, absorbable by the fluid (hygroscopic). Also a solvent, DOT 3 can hurt your car's paint should it get on its surfaces.

DOT 4
DOT 4 has a dry/wet boiling point of 446/311 degrees Fahrenheit. It is made with borate esters to defend your car's brake system from the acids that come from the fluid/moisture mixture. DOT 4 costs more than (but can mix with) DOT 3. However, manufacturers advise flushing one before filling your car's brake system with the other