I've just bought a 1986 Ford F700 dump truck. There is a small hydraulic reservoir welded between the frame rails. There is a filler plug on top that is just a typical pipe plug. There is no vent anywhere in the system. The first time in a day that you lift the bed, it sounds like the pump cavitates. Sort of a rattling sound out of the pump. After the first lift, everything is fine. Subsequent lifts are smooth and quiet. I notice that after the first lift, if I remove the filler plug, the reservoir is slightly pressurized. I wonder if it should be vented with a breather cap or something? My thinking is that no vent might be causing a shortage of flow to the pump on the first lift, but lowering the bed might be slightly pressurizing the reservoir and actually helping flow on additional lifts? Thanks, Greg
The filler cap on mine is vented. Mine is a 1989 ford f700 with the 6.6L diesel. I am looking for a wiring diagram for my truck. If you have a contact please let me know.
It sure sounds like it needs a vented cap/filter. I have a GMC Topkick with a twin cylinder double acting grain box. It has the reservoir between the frame and has a vented cap.