89 300E

I thought it was the modulator leaking, but found it holds vacumn and the line is dry. While I was down there, I noticed that ithe secondary pump does not leak unless the motor is running. Under pressure, it leaks out of the seals at the secondary pump.

Is the repair process to remove the pump off the three allen key and the single bolt and then reassemble with new seals? or to remove the circlip in the center and pull out the center pieces and replace the two O rings?

Help.