I'm not sure if there are any 'suction' hoses as they are all 2-way cylinders, so I am assuming the direction of pressure just reverses.Hopefully the filter has kept that from being circulated.
I'd suspect that is possibly from the inner liner of a hydraulic hose, possibly on the suction* side .
If that is on the 1958 machine old aged hoses would be my guess.
*suction side hoses tend to outlast pressure and are often of a much poorer grade.
OK, thx...none that I'm aware of...When I suggested 'suction hose' I meant from the tank to the pump, that is if a separate tank is involved.