Need Cummins N14 rebuild advice
 

It is all a diabolical Riddel to the Fidel

Check for cracks in the step. If its solid measure depth, if out of spec there are mobile service that cut depth and Cummins offers shims to bring the liner back to correct spec. If there are cracks they can also repair that. Very common. Also if marginal sealant can be used under the liner lip. Use Crisco on the liner orings and make sure the two round ones do not roll.

I think the N 14 is very similar to the Big Cam If the ledge is cracked it is machined out and a insert is installed. It's a reliable fix and there are mobile services that do it. We had it done often. Don't use shims unless the ledge is cut if the sleeve sits too tall it will crack the ledge.