1989 jag xj6 getting a crazy thumping sound when I start the car coming from the brake module that is by the green hydraulic reservoir and it sits on the inner fender well. almost sounds and looks like its trying to pump fluid. there's one line going (or from ) to the green reservoir and one line going (or from ) to the module that sits in front of the engine by the fan blades. the reservoir is full of oil, but I had a leak and it all ran out, but its full now, could there be a air pocket in the line or module, is there a way to bleed that system, tried to gravity bleed it from under car at the ride leveling/low brake pressure module, but nothing came out. any ideas, thanks mike