Originally Posted By: Bluestream
Originally Posted By: Big Jim
You may be interested to learn that all brake fluid is synthetic. It has been for decades. IIRC, sometime in the 30s.
There were no synthetic fluids in the 1930's
From internet: What’s new in brake fluids?
Non-silicone based synthetic brake fluids. Sometimes referred to as DOT 5.1, it is compatible with DOT 3 and DOT 4 brake fluids. This fluid is advertised as “synthetic” but has much the same characteristics as DOT 3 and DOT 4 fluids. This biggest advantage is its higher boiling point of over 500 degrees F, similar to silicone-based fluids. As long as the container says it is compatible with DOT 3 or DOT 4 fluids, you can mix it or top up the brake system with this synthetic fluid. Better yet, take the vehicle in for service and have the old fluid bled out and new fluid installed in your brake system. The brakes will perform better, and you will have delayed the onset of more costly brake repairs.
Right, because glycol ethers are naturally occurring, right? If it's not a naturally occurring element and is created through a chemical process, it can be considered synthetic. Any company that advertises it is simply using it for marketing purposes. Go to the store an see how many DOT 4 or even DOT 3 fluids are being advertised as synthetic.