Rack and Pinion Slide repair

My Power Gear slide mechanism has roller access inside the basement bins and inside the cabinets. The roller access on mine in the bins is covered by a black plastic box screwed to the underside of the floor beneath the slide, to keep dust and debris out. I just adjusted all the rollers on mine...found that two of them were not even making contact with the slide floor, and consequently, the slide was actually "sliding" along on the rubber seals and was out of square with the opening, causing the seals to not seal and letting rain come in.