Dyson, Best Buy, eBay and Amazon.com all have replacement belts for Dyson vacuums. Most suppliers have both Dyson factory-manufactured belts, as well as aftermarket brands such as 3M and Eureka. Should assistance be needed to select the correct belt model, Dyson.com offers a parts search by serial number.
To replace the belt, turn off the vacuum and unplug it. Use a flat head screwdriver to turn the slotted screws on the soleplate one-quarter inch counter-clockwise and remove the plate. Remove the brush roller and the old belt. Install the new belt on the motor shaft and brush roller. Replace the brush roller with the curve side of the end caps pointing down. Re-attach the soleplate.