VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Brake Fluid Compatibility

I installed rebuilt front brake cylinders last year in my ”˜37 Coupe and used DOT 3 fluid to top up the master cylinder. I bought the car about a year ago and do not know what brake fluid was previously used. I’ve put about 500 miles on the car since rebuilding the brakes and they have worked fine. Has anyone had experience with mixing DOT 2 (oil based) and DOT 3 (glycol based) fluids? From what I can see, the fluid in the master cylinder looks clear, no gumming.

Dot 2 is very rare and relly not sold any more. Dot 3 and Dot 4 can be mixed with no problems. A test would be to put some on a painted surface. Dot 3 and 4 will remove paint.