Reservoir foaming after plow raised/lowered - cause?

lhfarm · May 7, 2016

This is on a 1949 jeep, with a crank-driven pump attached to a Newgren lift. The Newgren uses a one-way cylinder that has a bleeding port at the bottom of the ram. That bleeder hose is attached to the top of the reservoir. I added a pressure relief valve between the pressure side of the pump and the control valve, with the relief side going to the same fitting as the bleeder hose. The original design had no pressure relief and the vent/filler was plugged, according to the installation instructions. I added a breather cap.

I had asked for and got advice on stopping a suction side leak at the pump. That fix worked. As long as the jeep is idling (and the pump running) there is no aeration (foaming) as observed by watching the filler/vent opening. On raising the plow and then lowering it repeated times, fluid starts rising in the vent until it starts to overflow and appears to contain air.

I can't find any evidence of leaks on the valve connections and the plow operates as normal (lifting). How can I determine where the air is coming from or how do I correct this problem? At wits end.....

Thanks,

lhfarm · May 16, 2016

Just as a follow-up

The problem was a failure of the gasket between the control valve base and the reservoir. The control attaches directly to the top of the reservoir. When doing the restoration, I had used a gasket maker and not an actual gasket. I incorrectly assumed there would not be any pressure on the junction. Once a real gasket was installed, the lift is working as intended.