In Reply to: 1954 NAA Hydraulic Problem posted by Steve Diehl on February 19, 2019 at 10:44:09:
A common scenario for these tractors. The most likely culprits are a leaking lift cylinder and/or a worn pump. In both cases the offending component starts to bypass pressure when the oil temperature increases and viscosity drops. Generally the relief valve wouldn't exhibit this behavior - it would leak more when the oil is cold and pressure is higher. The lift cylinder is by far the cheapest to fix. Pump replacement/overhaul is relatively expensive.