The hydrualic pump on the front of the 84 500sel seems to be leaking from the bottom when the motor is running. This pump feeds the strut system to all four wheels. Does anyone know if there is a rebuild kit or an o-ring that could be replaced rather than installing a new pump? Also, is there some way to find out if this pump is the same as the pump used on the 560? I'm tempted to take it off and see, but I hate to take the chance of making it worse without a backup plan.