Good morning Brian.

You will hear some extreme views on this subject including the statement that DOT 5 always yields a "soft pedal". In order to believe that you will have to believe that what we learned in our physics classes, that fluids are not compressible, is incorrect. This subject is all over the car/truck forums so all the information you can possibly digest is out there.

I use DOT 5 in my restored '36 Chevy pickup and in my '32 Ford roadster street rod. The purpose is to avoid the "paint remover" effect of DOT 3 & 4, especially on the roadster where the front brake lines pass through the exposed frame rails. In my experience successful bleeding of DOT 5 requires waiting a day or so after pouring the fluid in and doing the actual bleeding. On the subject of bleeding I just discovered "gravity bleeding" that makes bleeding a 1 person job if the MC is above the level of the wheel cylinders/calipers. I wish I had discovered that decades ago. It really works!

DOT 3 & 4 advantages- inexpensive, easier to bleed. Disadvantage - removes paint.

DOT 5 Advantages & disadvantages - opposite of above.

If you are into the brakes anyway you might consider using asbestos shoes. They are abundant on ebay and work way better than the "organic" friction that has been manufactured since about 1980.

Good luck with whatever you choose.

Ray