Hey at least you didn't have to go and buy new tires on top of it all !
If you want one right the only way is to do a COMPLETE tear down and fix all the years of use, abuse and neglect. Long ago I figured the only way I could live with one was to know it was right all the way thru so I always tore them down to a empty case and started back up from there. Many times using good used parts from several other machines to get it done. That's why I have not done any in years just takes too much of a financial and time commitment.
At the very least at this point I'd split it apart and put a new gasket in there. Not bad to do just block the front out wide so it doesn't flop over ! They all leak there unless they have had that gasket replaced.