I would have thought that the perimeter foundation drain would have been done when the rest of tbe foundation was built. Good luck.

Thanks. Yes, I mean filling the cinderblock with grout. We're still not sure which way to go... we're told that there was a new perimeter drain installed on the outside of the old/original foundation wall, but they didn't do one for the interior of the wall (they didn't want to break up the floor).

#2.

Best way to deal with something like this, if to allow the water to bypass the block and drain out under the slab. The water will percolate into the ground below the slab or find its way into the sump pump. We do this all the time and this method is approved by most engineers.

The way this is done, on the problematic wall, you cut a narrow strip of the slab near the block wall 4' on center (strip to cut 3" x 8" big enough to install the pipe), drill a hole in the block and install a 3/4 PVC pipe with a 90-degree elbow and fill the cut portion of concrete with cement. If you handy enough it can be done DIY with a few tools you can rent for 1/2 day rental, if not you can hire a local masonry contractor and they can do that in one day. Here is a cross section so you get an idea.

Filling with cement is not a good idea, you will not fill cinder block cells solid enough to prevent water seepage it will be a waste of time, money and too much work. If you have a cracked concrete wall the repair can be done by installing injector ports and the crack can be filled solid using epoxy.

Curious how one would know just what blocks to drill?

Every time we've had to cure a leaky wall from no obvious source, we excavated from the outside, replaced footer drains and waterproofed. In the old days, it was layers of bitumen-saturated fibre glass followed by fibreglass drainage/insulating mats. Later, we used plastic waterproofing membrane.

I remember the good old days you talking about, we use to install steel I-beams when we had bowed foundation walls...today we install carbon-fiber straps 1/8" thick encapsulated in epoxy and they 10 times stronger than steel and do much better job. :-)

We have seen solutions that use epoxy to fill the holes.

If you have a large portion of the wall exposed and are planning on finishing off the space, installing an interior drain tile system may be the most cost-effective route.

The best solution though is to fix the issue from the outside. Unfortunately, this is probably the most expensive route and will cause you to dig up around your foundation and may require the removal of any landscaping, porches, decks, etc.

In my own home from the 1930s with a cinder block foundation, I chose the interior drain tile solution. It's been dry for 4 years and we have now finished off the space with drywall and flooring.

Here is a good article from US Waterproofing, a local Chicago waterproofing company. We used them for our house and they have great blog posts explaining the common basement seepage issues: http://www.uswaterproofing.com/learning-center/basement-crack-repair-6-things-you-need-to-know