During very wet times I have water leaking into the basement around the septic pipe. I plan on digging below the pipe and running drain tile away from the house but also want to re seal the pipe. Do I need to remove the current sealer. And what is the best product and way to seal around the pvc pipe
I'm not a pro, just a long-time DIYer, and I'm sure that there are other products, but I would use black plastic roofing cement. It will seal in the rain, and remains a bit flexible.
However, it is a very sticky mess to put on. Use throw-away rubber gloves, old clothes and flat sticks (paint stirrers work) to smear it on.
It will definitely seal a leak.
I'd suggest leaving the roofing products for the roofing projects.
Remove the existing sealer and clean the concrete around it to the best of your ability.
Get yourself a product called hydraulic cement. Hydroplug is a common brand. It comes in small tubs and you can get it at most good building centers/hardware stores. Use your fingers and a putty knife to pack it around the pipe, working to fill the annular space between the pipe and the wall as deep as you can. When hydraulic cement dries, it doesn't shrink at all like regular concrete does. So, it is great for sealing out pesky leaks. It is what we require on all new homes.