If you don't know the age of your brake fluid, then yeah, your best bet is to flush the system or bled the old fluid out while feeding the reservoir with fresh fluid,[DOT 4]. This way your Great White North vehicle won't suffer any frozen moisture in the brake system[sorry, could resist the old SCTV joke <img src="/forums/images/graemlins/shiner.gif" alt="" />] Water in the brake system is no fun......

'92 SR Montero, Green, with 31" Yokohama Geolandar A/T Plus Tires, Mitsu factory fog light kit, on-board air compressor,Sony Radio and 10 disc changer. 213K and counting.....
Stock & Happy otherwise