'91 VW Passat, 205,000km. Power Steering fluid is under pressure in the reservoir. If I take the cap off while the engine is running, fluid will shoot out several feet straight up. It is constant when the engine is running, regardless of whether the wheel is turned left, right or not at all. In normal use it blows all the fluid out through the reservoir cap, but until it does, the steering system works (ie feels) normal. Is the problem in the rack or the pump? Is there a bypass valve that is easily repaired/serviced without having to replace a major component?