Old house. was a dirt floor basement at one time, over the years it has been cemented but is only about an inch or two thick in most places. Last year In a hard rain water comes up through cracks and holes. I have lived here for 25 years and never had a problem. I am afraid to just patch them because it would be never ending. All gutters lead away from house and I put a sump pump in. I think I found the problem. There was a 2" stand pipe that I think they used at one time for the washer. I broke the cement around it to see what was under there. It had a 90 degree elbow leading into a 4" tile. The pipe had rusted away and the water was going under the floor. I don't know where that tile goes to, it is at least 12' long. I think it possible leads into a sistrin. Waiting for a good rain to verify that is where the water is coming from. What would happen if I just plugged it up. Thanks for any help.
It is guesswork as to whether plugging up that drain pipe willl prevent flooding because you don't know for sure where the water is coming from. A hydrologist or a geologist may be able to make a guess that is more educated.
If you get enough rain the water table (in the ground) will rise to be above your basement floor level, and the basement will flood anyway.
The traditional method of preventing basement flooding is to install a perimeter drain system of perforated pipe (that provides an air pocket below floor level going all the way around your basement) for the water to gravitate to instead of seep up into your basement. The drain system empties into a pit (sump) where you have a sump pump sending the water far enough away that it doesn't seep back into the ground nearby.
A sump pump with no perimeter drain system will protect only against water seeping in within a few feet radius (horizontally) from the pit. (A greater distance if the ground is very porous for example of gravel or coarse sand.)
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.