I just purchased a 1979 Tiara with the mercruiser 260. I believe the stern drive is a an old pre alpha MR stern drive. The marina where I picked up the boat had just rebuilt the rams with new seals and 1 required a new cap and tube. The trim will go up, but will not trim down. There used to be trim sensors on the drive but one is missing now and the other one has the wires cut. I removed the trim motor and pump assembly and cleaned it out. I bled the system thinking that may be the problem. The motor works in both directions, so I don't believe the motor is the problem. I checked the reverse lock out valve, but am not sure if this has anything to do with the trim down function. I physically moved the reverse lockout valve to various positions, but there was no difference. I'm still not sure if it works. Can it be bypassed for troubleshooting purposes? I checked the hydraulic lines from the transom to the trim actuators, but do not know if they are properly connected. There are two lines to each actuator and currently the forward lines go to the forward ports on the hydraulic manifold located at the base of the drive and the aft actuator lines go to the aft ports on the manifold. Is this correct? I would appreciate any input from other members of the forum to help me resolve this problem.<br /><br />Thanks