Brake fluid can get old and eventually cause brake pedal fade in a high mileage vehicle. I found that out once on an older used vehicle. I figured a good brake bleeding would fix the problem but it didn't. I then opened the bleeders pumped it all out, added new fluid and did bleeding operation again. That did it, good as new. Now on all my vehicles I have used a turkey baster. Every time I change oil I remove the fluid from the reservoirs with the baster and top off with new. Although this will never give you all new fluid -- if this is done on regular intervals -- it will keep the brake & power steering fluids fresh enough to never need replacing. IMPORTANT -- DO NOT REMOVE ALL FLUID FROM THE RESERVOIR OR YOU WILL GET AIR IN THE SYSTEM. Always leave fluid covering the outlets on the reservoir.