Hydro System Not Working properly?

I have a converterble mower with your dual hydo pumps on it. the right pump oval shape top with the two allen heads broke off while not in use. the sysem dumped my fluid. After having screws in the head removed, I put it back togather and reserviced the resavoir. However when I now move the levels the with the mower running there is no response, no engagement, mower donot move. I need your help, do I need to bleed the system?