Here I am again with the same problem and can't seem to figure it out. The left pump is new and as you can see in the pics, doesn't have any leaks but does not work as it should! The right one is completely covered in fluid and appears to be leaking, but is very strong. I can feel a groaning/grinding sound when the left side is under load, however, when the wheels are off the ground, they both appear to rotate normally. Fluid was changed, system was bled, all fittings, bolts, valves, etc are tight. Does the leaky but strong pump have something to do with the completely dry, but useless pump?