beware of any system which forces fluid back through the system from the calipers unless you have verified that it is acceptable in the car manufacturer's own service procedures. Some European cars, such as SAABs (from before the GM seizure) and Ford Taurus SHOs, for instance, use a system in which the ABS pump serves as the power booster for the whole system, and forcing fluid backward through these is likely to seriously damage a $2000. part, leaving you with not only no ABS, but only leg muscle powered brakes, which isn't good, even for an old running back like me.