Last fall while loading & hauling topsoil with a Dearborn rear scoop, my 53 Jubilee hydraulics suddenly stopped functioning. The lift would not raise the loaded scoop. After shoveling out and unhooking the scoop, I discovered the three-point would raise very slowly and with very limited weight. I parked the Jubilee and used the 49 8N to finish spreading topsoil and other tractor work.
With fall and winter projects under control and spring approaching, it was now time to investigate the Jubilee hydraulics. The piston pump was rebuilt just a couple years ago and I had also replaced the hydraulic piston, O-ring and added fresh hydraulic fluid after cleaning the sump chamber. I was not anxious to remove the hydraulic lift cover, etc. again. The hydraulic pump seemed to be working as normal. There were no leaks from the lines under the tractor or from the pump. But I did notice a little hydraulic fluid drip from under the upper lift arms next to the lift cover. That was odd.
After reading my various Ford manuals, I consulted with JMOR, hydraulic guru, regarding the issue. He further explained the hydraulic lift operation in the Jubilee and sent detailed photos. We focused on the three safety/regulating valves in the Jubilee hydraulic system, specifically the safety relief valve. He suggested I chain down the lift arms and observe inside the sump chamber through the hydraulic fluid fill port.
I did as he recommended and as expected, observed a stream of hydraulic fluid coming from the safety relief valve. The stream pressure varied with engine (pump) speed. The relief valve was doing it’s job. I unchained the lift arms and while raising and lowering the lift arms, observed in the chamber again with a flashlight. No leak or stream of fluid was visible from any of the valves or anywhere else. That seemed good. Then I noticed the lift arms were raising much faster (normal?) and the whole system “sounded” like I always remembered it operating. I wondered, would it lift a load? Could I be so lucky?
The heavy Dearborn Type E tandem disk is inaccessible out in a muddy field. So I attached the Dearborn Economy model back blade and loaded it with as much weight as possible. The Jubilee lifted it at a normal rate with no problem numerous times. Sweet! Okay, so what was the problem? What did I, albeit inadvertently, fix?
Jesse had suggested the problem could be debris or a blockage affecting operation of the safety relief valve. He was correct. The valve was likely stuck partially open, releasing hydraulic fluid and thereby affecting both the speed and capability of the three-point to lift normally. If I would have observed in the chamber before chaining down the lift arms, I bet there would have been a lesser stream of fluid from the safety relief valve. Chaining the lift arms down forced the relief valve open under full load. Apparently whatever was blocking it cleared, as it seems the problem is solved. Much obliged to Jesse for his assistance. Thanks.