Had an issue with my ~2002 Cox New Generation ride on lawn mower. These Australian made ride on mowers are renowned for their robustness and easy repair with basic tools. But, they are not particularly well designed/engineered in all areas and have had their fair share of issues.
This model has a weak point in the plastic steering box. The box is a 2:1 and angle drive in one. The output of the box drives a square shaft. The output is a glass fibre reinforced plastic gear with a slot cut in it and a hose clamp to tighten to the shaft. This is a terrible idea and the system was dropped quickly from later model revisions.
Not being able to easily get parts for this mower anymore given its age (and not to mention that a replacement gear would likely fail again anyway) I decided to modify the output gear using an old socket, couple of large washers, and a few bolts.
- Cut 1/2″ socket in half (half inch socket fits nicely on the square shaft.
- Weld socket to M12 x 37 x 3.0 washer. I welded completely on the inside through the hole of the washer and and a few tacks on the outside that you can see in the pictures.
- Drill three holes in washer and another washer to match. Countersink the washer that will go inside. Don’t worry there is plenty of room for the washer and even bolt heads if you don’t have countersink bolts.
- Cut off protruding plastic from crown gear and sand flat to accommodate washer/socket.
- Match and drill holes in crown gear.
- Sandwich crown gear with socket/washer and second washer using 3x M5 x 20mm bolts.
- Enlarge gearbox output cover hole to accommodate larger output.
- Reassemble and enjoy nice tight steering that doesn’t slip.
Cox Part Numbers for the steering box.