Product review (4 stars): For Few, Small Spots
It would be very time consuming and tedious to repair a dish rack with many rusty spots using this product. The more spots you have on you dish rack, the worse it will be. I would use this product at the first sign of an issue.

After removing each dish rack and attached accessories (difficult). Examine each rack for additional breaches in the vinyl. You have to cut back the damaged vinyl to expose the rust. Then clean the rust, which is much easier to do with a power tool. Clean any dust and debris left by the previous step. Then apply 2-3 coats of the (liquidy) vinyl solution. Wait 8 hours before running an empty cycle with detergent.

My dishwasher rack was too far along for me to waste my time with this. But it may be useful in the future.