The John Deere STX came in two different models, the STX38 and the STX46. This lawn and garden tractor series was manufactured from 1988 to 1997. Both models featured a Kohler single-cylinder engine; the STX38 produced 13 horsepower, while the STX46 produced 15 horsepower. The cutting deck on the STX38 measured 38 inches and the STX46 had a 46-inch cutting deck. John Deere STX tractors have a dry disc brake located on the outside of the transaxle that requires periodic maintenance.
Park the tractor on level ground and remove the key from the ignition.
Place the jack at the rear of the mower. Make sure the jack is under the frame and not the transmission. Raise the mower and place jack stands under frame behind the rear wheels. Lower the jack so that the tractor rests on the jack stands.
Pull the cap off the rear right tire, exposing the axle rod and "E" clip.
Remove the "E" clip using the flathead screw driver. The tire will slide off, and the brake disc will be exposed.
Tighten the nut in the center of the plate connected to the brake disc one half turn, using a 13mm socket.
Place the gear shifter on the right side of the fender to neutral. Make sure the emergency brake -- located on the left side of the mower on the deck -- is off. With your left hand spin the exposed axle. With your right hand slowly depress the brake pedal.
If the axle stops rotating the brake is adjusted. If it keeps turning, re-adjust the brake disc nut half a turn and keep adjusting it until the axle stops rotating while the brake pedal is depressed.
Reinstall tire, the "E" clip and the tire cap. Lower the mower back to the ground.