Noticed on a can of brake fluid I recently purchased that it was synthetic. Asked the man at NAPA if all brake fluid nowadays was synthetic and he said NO. Is this compatible with our old trucks? What happens if you mix it with non-synthetic?

Wish things would quit changing. I'm getting too old for this.

 

I use whatever plane jane DOT3 is availbale on my 51, 52, and 78 Fords, as well as my everyday driver.

 

All I've looked at was DOT-3 but some say synthetic and some don't. All I want to know is there a difference.

 

Do not mix them. Very bad.

 

The problem is not synthetic brake fluid, but silicone (DOT 5) brake fluid. DOT 3 is DOT 3. DOT 3 is hygroscopic (water absorbing) and DOT 5 is hydrophobic (non-water absorbing) and mixing those causes corrosion in the system due to moisture build up. Feel free to use it as long as it is DOT 3.

-Stephen

As a side note, DOT 3 has always been synthetic. The inclusion of the word synthetic is a marketing trick to make it look like an improved product and to persuade fans of synthetic products (oils and such) to continue purchasing their products.

 

I knew about the silicone base fluid and the hygroscopic part the synthetic part just confused me. Guess thats to make the tree huggers happy