Change my oil, spark plugs and wires yesterday. Started the vehicle, 92 explorer xl, went to put it into gear and it grinded, stalled and the clutch lost all pressure. This had happened before so I bleed the system. Got pressure back, started the vehicle and the clutch immediately lost pressure again. Repeated this process a couple times with no success. As soon as I start the vehicle it looses all clutch pressure and is unfunctional. Any ideas?