If i plunge the hole in my basement floor drain and air bubbles come up from the cement about 3-4 feet away?

Does sound like you have a problem with the pipe. You should open the floor and replace if you want to be free of future headaches. If you have replaced sections before it sounds like the lifespan of your system is running out. Is it old or just poor quality/instalation?

ok, You have a concrete basement floor. Should you consider just replacing the entire run in the floor? I would, why have to go throught this again? It is going to be a big job and yes a pro would get it done quickly and you would not feel any pain except financially. But dont you want to handle issues yourself?

If you do....you have to cut the floor and remove some or all of the pipe. You have several tool options....

You want a clean straight cut on both sides of the pipe. It will be easier to fix and work better.

Best option is to rent a water cooled "Ring Saw" it will produce a clean cut and will go through it like butter.

A Ring Saw has a ring shaped blade without a center and is driven by a rotor bearing. Being water cooled it will make NO dust. any other method of cutting into concrete will fill your basement, hair, eyes, pets, family with the fine dry dust. Yes, it will make the floor wet, hope the area isn't finished. But it will be much easier to sweep the water into the hole you create than spending weeks getting that dust off of everything!

Chalk a line where you need to cut and cut it. The floor is likely about 4-5 inches thick and set ontop of loose stone. The small ring saw will go through 8 inches so no problem.

Now you have these 2 grooves cut into your floor, you will need to break the concrete into smaller parts to lift out and discard. You can do this with a small jackhammer/drill called a "Roto-Hammer" looks like a very big drill and will accept chisel type bits that will break it up.

Or, you can have success with a heavy sledge hammer but you risk doing damage to anything (including the pipe) that is under there. Plus, if you are landing that sledge right over the pipe and happen to force it downward you could change the angle at which it lays (called Pitch) and end up replacing it at the angle you see when you open it up. Pitch is very important.

As for your stairs, Is the bottom of the stair run resting on the area you need to access? Do you have to get to the area under the staircase and is it drywalled in? The run of stairs, weather a half floor run of say 6-8 or a full floor set of 12-15 is not easy to just "move". Modern sets are attached at the top through a "stringer", nailed or screwed to the upper floor frame or in a half set, to the landing or platform. Also it will be attached through the "stringer" (the left and right sides) to the wall studs going down if there are any. Get to underneath and try to "sawzall" the nails or screws.

If you can avoid it, do. Can you stop your cut in front of and behind the stairs, knock out the concrete,leaving the area of floor they are resting on intact, reach under and dig out the stone and pipe and pull it out from underneath? Maybe have to break the pipe so it will pull out?

Do what you have to there.

I dont know what type of pipe you have or what type of joining connections are present so you will have to use your local hme center to help you replace it correctly. Worst case is you can buy a "Fern-Co" union. Basically a large rubber sleeve with hose clamps on it and join just about any type of pipe.

Remember! You need a pitch of slope on this pipe! You cant ever be any lower than the pipe outside and standard pitch is "1/4" per 1 foot. That means that if you hold a 2 foot level on the pipe and hold it level. You will have a 1/2" gap at the low end. 1" for 4ft level and so-on.

Fix your pipe and now lets fix the concrete.

Replace the stone to the level that is under the undisturbed concrete. Buy "concrete adhesion primer" How much depends on how many feet of cut you have. It is a slightly thicker than water, sometimes light blue primer that helps the new, wet concrete, adhere to the old concrete. Even with it the patch can move indipendently of the old slab. The only fix for that is to buy short pieces of steel re-bar, use that roto hammer you rented and drill appropriate size hole in the face of your cut on both sides horizontally and epoxy the rebar into them so half is sticking out into your cut open area.

Buy concrete in whatever form you need, (bags & wheelbarrow, bags & mixer, order a truck to deliver....) and fill the hole. Use a 2X4 about 1 foot longer than your cut is wide as a "screet" once the hole is full of wet concrete, run the screet along the finished floor to even it out with the new stuff. Shimmy the screet back and forth along the patch with about 6 inches resting on the original floor on both sides and slowly pull it back along the patch untill you reach the end and everything is pretty level.

Buy a Magnesium hand float or trowel and gently smooth out the surface. The small stones in the concrete will push down and the surface will

if it is connected to your septic system and has a "p" trap you need to make sure the trap remains full of water. If the water evaporates then there is nothing to stop sewer gasses form coming in. If there is no P trap then cap the drain unless it is needed. If you see murky water then it probably doesn't have a trap and make sure the drain is not plugged to get rid of the murky water. What else is the drain used for? If it is just for the ac drain and not to the septic system then you can put a rubber cap on it and prevent air flow up.

a concrete cutter will make a nicer cut and prettier repair when your done but depending on the size may be hard to get out of the hole you don't want to use a jackhammer a chipping hammer would be easier to handle, may I suggest both, use the concrete cutter to cut the section and use a chipping hammer to break it up into manageable pieces

rent a walk behind saw, if you have the room to use one, you can also find a quickie saw with a hook-up for the garden hose to keep the dust down...then use your jack hammer or demo hammer to remove the cut concrete...

Definitely sounds like a break in your pipe,take it from someone who knows,hire a proffesional! I tried to fix mine once and ended up messing it up worse!