1999 slk230,My actuator arm that opens the trunk when retracting the top snapped near the threads to the connection. I've ordered a newpart frommercedes. Is their anything to look out for or tricks on making the connections to the pump and does it have to be rebled with fluid, I think the new part comes with fluid in it.Myactuator arm snapped at the top of the arm near the threads. Thanks for any help!