this subject has been discussed multiple times in the past.

in my OPINION. you should not flush unless you plan on completely disassembling the ENTIRE brake fluid system.
even if you "BLOW' air thru the system to get rid of the flushing fluid. some will still remain in the system. the wheel cylinders and calipers will be big holding spots.. the flush fluid will degrade the new fluid unless it's completely removed. it will compress at a different rate as brake fluid causing soft pedal problems.
just adding the new fluid forcing out the old. will still leave some old fluid in the system. at least this old fluid won't degrade the new. it won't "MIX" but they won't jell or cause compression problems. they are required to be COMPATABLE by LAW.


i have done this conversion at least 30+ times in the past. it's probably more, i lost count on the actual # it's been 15-20 years since i have done this.
i just add new fluid and pump out the old with the new.
i never has any real problems doing this.

just remember. DOT 5 retains AIR like the old stuff does water. NEVER SHAKE the bottle of DOT fluid this can create problems.
i also liked to leave the new bottle in the sun with the cap off for a few hours to help remove air from the fluid.



as others have posted. whatever you do remember to regurally flush this fluid at least every couple of yeaars.