15 years ago we added an extension to the old cinder block foundation which is now 60 years old. The new extension is also cinder block. Where the old and new meet, we have a leak. I put hydraulic cement in the inside seam (first picture) but that did not stop the leak. Ideally I'd just dig up the outside and waterproof the wall or pour cement on the flat earth to seal it, but my three A/C units sit there and I was quoted $2,000 to move then re-attach the units (this is New York so it would be expensive). The second picture shows where the new and old foundations meet, at the end of the siding (new foundation continues the wall). I've tried to grade the slope with gravel which didn't help.
I'm thinking about chiseling away the inside seam this time and forcing cement into the bigger crack. My concern is that since both walls are cinder block, the water is inside the block and unless I fill the block completely, chiseling will make the problem worse.
Any suggestions? Thanks in advance