I have an older 300b that I am having hydraulic problems with. last time I went to dig out beaver dams I noticed lots of hydraulic oil coming out underneath at the hydraulic filter. when parked all of the hydraulic functions worked as should. I pulled the filter and the o-ring had been put on wrong last time and had blown out. went back a few weeks later and I got a new filter and o-ring and put it in. added 9 gallons of hydraulic oil behind the seat. now I have almost no hydraulic function. I can lower and lift the stabilizers very slowly but if I stand on it, it won't lift me up. I have let it run for about 20-30 min with no improvements. is there anything else to priming the hydraulic system? thanks for the help.