All the brake fliud should be flushed out. By removing all the liquid in the Reservoir first, than fill with new fluid, you will speed up your job as you do not have to "push" all of that fliud through the system before refilling the master reservoir with new clean fluid (no mositure) or discoloration.
Using a pressure bleeder pump makes the job easy as you get to flow a lot more liquid at one time than the older "foot on the brakes - pump it" method. Besides you avoid the chance of tearing up the master cylinder pump seals by pushing too far down the bore into the ruff and possible scaled area where the rubber mater cyl pump seals will get damaged.
Flush every two years and you will avoid a LOT of brake issues especially mosture damage to calipers and lines.
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2005 X5 4.8IS
The
Blue ones are always FASTER....
Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green