Element3™ Rear Drum Brake Wheel Cylinder Repair Kit (WK13) by Raybestos®. If your wheel cylinder bore is still in good shape, this repair kit is an economical alternative to a new wheel cylinder. It includes the spring, cup seals and dust boots. Element3™ brake products deliver a new level of control and confidence to drivers. Their premium brake line delivers what you’ve come to expect from The Best in Brakes® with the addition of upgraded product attributes.