Hello! I have hydraulic oil leaking from the lines on the top of the valve bank on the old 225D Cat excavator. I would say they are hard from the heat over the years. I have new ones now and plan to chane them all out. I assume that the valves are all closed and the only oil I will lose is what is in the lines. What I am wondering is will there be any valves that could be open and possibly let oil through the pump from the tank. Should I pump out the tank? Also, what should I do about air in the system after new seals are in? Just run it slow and work the air out? Thanks!!
Yes drain the tank, change all of your filters, clean out debris from behind the screen in the main filter canister. Try to get a pump with a filter on it to put oil back in with if it,s good. Replace every line seal and plug seal on both valves, would be a good time to reseal the main relief combiner and summing valve, it's all in one piece but be carefull taking it apart. Get everything back together right. Later Bob