This instructable is to show how to fix an old shower door roller. Here is what you will need: 4(four)-626z sealed roller bearings, 4(four)-6mm dia. x 8 mm long pull dowels, 4(four)-4mm x 0.7x 6mm long panhead machine screws, 8(eight)-4mm I.D. flat washers. (All available through an industrial supplier such as McMaster-Carr) You will also need a Phillips or straight screwdriver, and a hammer. First, remove old screws and rollerwheels with screwdriver. Next, press pull dowel into roller bearings, making sure to keep it flush on one side. Now place bearing with dowel and 1 washer against slot in shower door, and washer and screw on opposite side and secure. Repeat for other 3 wheels. Make sure to place in approx. same location as old ones to maintain proper door alignment. If need rollers can be adjusted in slots to square the door to the opening.