There was an article in This Old House magazine (sorry Bob..) about using hydraulic cement to patch cracks in a foundation. according to the article, although it sounds opposite of 'fixing' a crack, one is supposed to enlarge the crack with a cold chisel, and then force hydraulic cement into the crack, quickly smoothing with the trowel and feathering the edges to blend with the wall using a moist brush. They suggested keeping a disposable bucket with water nearby to quickly wash off the cement from the brush and trowel as the cement sets quickly. Hydraulic cement is supposed to expand as it sets, creating a bond between the 2 sides of a crack. For what it's worth... good luck.