I am trying to rebuild an old goulds jet pump. I am having a hard time finding parts for this pump as it is old and obsolete. The main part I am trying to find is the seal/diaphragm. Would it be possible to find some of the diaphragm material and cut one out to fit? What are my other options.

The pump has a serial number beginning LS03-3. The number 53013 is cast into the front of the pump housing under the suck tube.

Any help you may have would be appreciated.