I use 5606 aviation brake fluid. Some like the lo flam stuff, but I have had no problems with the 5606 in my 6A nor with the 12. I bleed the brakes the usual way which is to pump the fluid up thru the system from the drain/feed port on each brake caliper. Just keep going till all the lines are red with fluid , no air pockets, and continue until the resevoir is about 3/4 full. That's it.
Dick Seiders 120093
I am not necessarily recommending this, but some aircraft owners use automotive Automatic Transmission Fluid (ATF) in their brake systems. It is compatible with the seals and works OK. I do not know about the flammability. One disadvantage of ATF is that it is not stocked at airports, if you ever need the brake fluid topped off while on a trip. Different types of fluid should not be mixed.
Joe Gores