I have two issues with my sidewalk that I'd like to repair once the weather stabilizes.

1. The slabs of the sidewalk have spread out over the years so that grass grows up between them. I've purchased the foam backer rod and self leveling liquid already. Some of the slabs, especially at the end of the driveway, are several inches apart. Will I have to use anything in addition to this?

2. One slab of sidewalk is crumbling badly (it looks like a bad patch job from a previous owner). A good inch or so is gone and the stones are constantly falling out. I'd like to fix it myself. I assume I'd clean it out until I hit something solid and then use a bonding agent and fresh cement?

Any answers greatly appreciated!