My 1256 has developed an engine oil leak, and I could use a little advice. It seems that the oil is leaking from the 4 bolts that attach the engine to the tube frame. Is it possible to tighten the bolts too much and punch through the pan? I rebuilt the tractor about 5 years ago and haven't seen the leakage until this past year. I snugged-up the bolts in question yesterday and still seen a little leakage this morning. Any ideas?