I bought some Dot 3 Brake Fluid about a year and a half ago and forgot I had it until i found it this weekend. I have not used it and it still has the seal. Is there a shelf life on this thing or am I better off buying a new one?

Are all Dot 3 Brake fluids the same? I think I bought mine at walmart and the brand is Preston.

 

Do a quick Google search on DOT3, DOT4, DOT5.. You'll find that the ratings are based on basic content structure and minimum dry and wet boiling points (dry being without water absorption).

To answer your question, NO not all DOT3 brake fluids are the same. In fact you will find some drastically different BPs, generally associated with price.

Read the back of the label, if there is a shelf life recommended by the manufacturer it should be stated on the bottle, if not .. call them if you still are wondering. Sounds fine to me, since it's still sealed.. Had it been opened the fluid would have probably absorbed lots of water from the air surrounding it (natural characteristic of brake fluids).

 

If you don't drive on the track then no big deal. If you do then you need a higher boiling point. Valvoline synthetic fluid is a good lower priced fluid you can find about anywhere..