brakes fading

My guess it is that the new brake pads are not seated on the new rotors so you don't have much braking or something else is wrong like air in the system. The compressability of DOT 5 and DOT 3 is the same.Thickness of brake fluid has nothing to do with it. We are not talking about oil here. The boiling point of DOT 5 is higher than DOT 3 so it would have probably been worse with DOT 3.

Like I said the other possible cause is that you have not gotten out all the air in the system. If air is trapped in the system then that caliper or calipers will not work so the other remaining calipers have to do all the work and they will overheat. I would re-bleed the whole system. If you have a brake pressure gauge then make sure you bleed the air out of the line going to the gauge also. All it takes is one bubble of air.

We had air trapped in our system and could not get it out until we used a Motive Pressure Bleeder http://www.motiveproducts.com/
That one bubble of air would not let the brake pressure go over 600 psi while standing on the pedal. Used the power brake bleeded and we could easily get 1300 psi after the air was out.

 

Been reading up on things. Strange does not recommend DOT 5 fluid but does recommend DOT 5.1 and DOT 4. They say that DOT 5 does not mix with other fluids. Not sure if that is your problem or not but I recommend rebleeding your entire system and putting in DOT 4 or 5.1 to push out the air and DOT 5 fluid. Also check to make sure the pads are square in the calipers. Put the car up on jacks how it is now and have someone push lightly on the pedal while turning the wheels by hand and keep on pressing the pedal harder and see if they all stop moving about the same point of pedal travel. What ever wheel does not stop shoeld be double checked. From my own experience if that pedal went to the floor indicates air in the system made worse by some brakes getting hot and probaly boiling the fluid.