Yes, I heard this does work but I would be careful. You don't want contaminated food. Pickles are made best when the jar is vacuum packed, fresh, from scratch. Vinegar is a good food preservative, just not sure it's the safest one if reused.
Used pickle juice is not good for making new pickles. Pickles need to be made by placing cucumbers in a sanitized jar with boiled water, vinegar and salt to kill all germs and then seal the jar with hot water to keep any other germs out. You can make pickled cucumber slices you make overnight and eat right away, but these are not pickles.