I can't help but notice that the "After I changed the hydraulic fluid it doesn't work" is a common situation. I haven't had that problem but I haven't heard anyone mention priming filters and top filling the system. I often see the question about where the level is on the dipstick though. I would like to share with you what I do and have been successful with. I drain the fluid. I pull the filters and open them up and check the filter media for contaminants. I do this visually and with a magnet to detect excessive wear or damage to parts. I then place the new filter in a can of fluid and let it absorb as much as it will and put it all together. Before I completely close up the cover I service the system with the recommended amount of fluid. I don't even look at the dipstick. It is so far off at this point that it is useless. Then I have a peace of thin 5/16" plastic tubing that just slips into the top of the filter cover and a little pump. I pump the oil in until I have as much coming out as I am putting in and quickly remove the tube and snug the bolts down and then just check to make sure they are all tightened evenly. Then I start the engine and just let it idol. Let it run for a couple of minutes and I start exercising the steering and the brakes and you can hear the fluid displacing the air that has been introduced to the system. The reason I try to prime the filter is because it is the single largest holder of air in the entire system. The more air you can get out before you start the engine the shorter the period that the pumps are running dry and once they prime and get the air out your troubles should be over. Run all your hydraulic components through and watch, feel and listen as you slowly and deliberately turn your steering wheel stop to stop until it moves normally without jerking and is smooth and quiet. (Unless it was noisy before you changed the fluid. I have seen some that were just naturally noisy.) Exercise your brakes until they are smooth and clear of air. Don't forget the PTO. Nothing more frustrating than getting into the field and engaging the PTO and nothing happens. Once you have everything up and going, Then check your dipstick and your level. Something else I do that isn't in the book is I do over service the fluid by about 2-3 gallons on my 1206. I do that so if I loose a little bit here and there which we all do hooking up equipment and disconnecting and just little incidental seeps and leaks. Yea I know someone out here is going to say "Quit making excuses and fix it right". Well la de da. I am not going to tear something complex apart to fix a seep that is not that critical. I just compensate for it. Well if this helps anyone then the time is well spent. If not them it won't make any difference. Good Luck with your next fluid change. LarryT