It has happened before, to factory planes as well
I would never use plastic or aluminum break lines near the caliper. I used a #2 hose like this.
http://www.raceplumbing.com/product_info.php?cPath=21&products_id=213
http://www.bonacoinc.com/teflon_brake_lines.htm
I ran the small braided line all the way from the caliper to the firewall. You could run a shorter piece of braided hose from the caliper, than transition half way up the gear leg to aluminum, but less joints and connections are better. The temp rating, flexibility and durability of the braided line is much better than plastic or plan aluminum tubing. When plastic was used many failed, but you don't hear about them and lucky even fewer caught fire.
The down side if any of the braided hose is a little more weight and cost. I had mine made up at an industrial hose house that had the proper 37deg fittings. The cost for the two lines was not much. Also before the fittings where installed I slipped a short piece of clear vinyl over the braided line. This was to avoid any abrasion of the hose braid rubbing the wheel pants or bottom of the gear leg fairing. Going for 1000 hours and 7 years and no problem. Also for maintenance when you move your caliper, the flex line allows the caliper to set it a side without disconnecting it.
Also people who know more about the subject state the Mobile 1 synthetic ATF works well and has double the flash point temp. The down side is there are other additives that are not really needed for a brake system, however those who use it say the extra additives have no negative affect on the brakes. Those who use it say it has worked for them for years. Apparently the additives like anti-friction or detergent compounds only work at high temps.
There are better Mil spec brake fluids, like MIL-H 83282, but only come in 4 gal quantities as I am told. It has twice the flash point of the older MIL-H5606 fluid, and some think it is just like synthetic ATF fluid. It would be nice if Van or someone who sells parts would buy MIL-H 83282 to sell in small amounts to builders. We can always make our RV's better and safer. No need to use 65 year old MIL-H5606 brake fluid formulas when MIL-H 83282 is available (kind of). I don't know if the two MIL specs are compatible.
Last DON'T ride the BRAKES! The best way to do it is check speed to a crawl than let them go *completely* (feet off) and let the speed build up, than check speed again, repeat as necessary. Just dragging the brakes continuously will give you a brake fire real fast. The process of brake / release allows some brake cooling. It is all energy and it has to go somewhere. Remember, also those cool looking low drag wheel fairings are not letting the brakes get much cool air.
Cheers George
(NOTE: I am not implying that this brake fire was avoidable or the fault of the pilot. It was constructed per plans as many RV's have this set-up. Also I am not implying he was riding the brakes. However I do know that many brake fires have been caused by riding brakes on all kind of aircraft, including small GA planes to larger commercial aircraft. If you have a long taxi keep that in mind.)
