Turn the ignition key to the "Off" position and allow the engine to cool completely. Disconnect the spark plug wire to prevent the mower from accidentally starting.
Remove the mounting bolts or screws from the rim of the left rear wheel; the type, size and number of fasteners varies by Snapper mower model. Pull the wheel off of the axle and set it aside with the removed fasteners.
Pull off the hub cap to expose the bolt holding the hub to the fender assembly. Remove the bolt and slide the hub off of the axle.
Take out the mounting bolts securing the fender plate to the mower frame. Grab the sides of the plate and pull it toward you to remove it from the mower.
Loosen the screw clamp holding the short boot seal in place. Slide the old or damaged boot seal off of the axle.
Remove the chain case mounting bolts. Pull the chain case off of the axle to access the long boot seal. Loosen the screw clamp and remove the damaged seal.
Thread the new long boot seal onto the axle and push it into place. Slide the retaining clamp onto the seal and tighten the screw. Replace the chain case. Install the replacement short boot seal on the other side of the chain case.