redstorations
New User
I have 2 Ford 641 tractors. 641 number 1's hydraulics hiccup under load only. NO visible hydraulic oil leaking from unit when observed through access panel, especially from rear of cylinder. Entire unit removed from tractor. Overhaul kit installed. New piston ring and all new "O" rings where cylinder mounts. Cleaned and polished control valve, new "O" ring on unloader valve, pilot valve removed, cleaned and polished, new "O" ring installed. Pilot/backpressure valve seat removed, cleaned polished and new "O" ring installed. Relief valve in bottom of reservoir removed. Both springs are in tact, ball polished, new "O" rings and and reinstalled. New "O" rings on feed and return lines in lid. Still hiccups. 641 number 2's hydraulics work properly under load, NO hiccups. I swapped units from one tractor to the other, first tractor still hiccups with the hydraulic unit from tractor #2. So I removed the relief valve and swapped those, still hiccups. Put the original hydraulic unit from #1 tractor in #2, NO hiccups. This seems to signify the problem is in tractor #1 somewhere. But where? Only two hydraulic related items on the tractor itself are the pump and relief valve, which I swapped already from tractor #2. Pump has pressure, not sure if it's loosing it internally, will put a gauge on it tomorrow. Feed lines that run through transmission seem fine as I am not gaining in the trans or loosing from the hydraulic chamber. Any insight would be appreciated.