Why does my steering box keep breaking?
The steering boxes on the Yanmar tractors are designed to last 30+ years without any problems. If you keep having problems with your gearbox then you have something else wrong.
1)- Do you have a loader or additional weight on the front of the tractor? Loaders are amazing tools and they work great on the Yanmar tractor but the steering system was never designed to be able to steer a tractor with a fully loaded bucket. Trying to steer a tractor with a loaded bucket puts too much stress on the steering box- especially if you try to steer while the tractor is not moving. If you get in the habit of hauling lighter loads or only trying to steer when the tractor is moving or the loader is sitting on the ground it will save you a lot of problems. Just remember - if you really have to work to steer the tractor you are probably close to blowing out your steering shaft... again.
2)- It may also be that the steering stops on your tractor are not adjusted correctly. Most of the Yanmar tractors have built in steering stops in the front axles that are designed to stop the front tires from turning too far when you are making a turn and the tire hits a stump, rock, or a hole. If these stops are missing or not adjusted correctly then the steering shaft will have to try to stop the tires from turning too far. The steering shaft is not built to withstand that type of force and will frequently be the cause of steering gearbox failure. There is a reason that they put steering stops on the axles - USE THEM &, IF YOURS ARE ADJUSTABLE- KEEP THEM ADJUSTED.
STEERING STOP ADJUSTMENT PROCEDURE (not all models have adjustable stops but most do. Some just use the steering arm hitting the frame rail or axle as a stop.):
Jack up the front end of your tractor.
Slowly steer all the way to one direction using just one finger on the steering wheel.
Stop as soon as you feel any resistance.
Turn back the other way 1/4 turn.
Adjust the stops to that position.
Repeat for the other direction.
3)- If you rebuilt the steering box yourself then it may be that you either did not get the pre-loads set correctly or the upper or lower races were not completely seated and they worked loose as you were using it. For rebuild instructions please check out our rebuild video here --
4)- If you have ever hit a rut or rock or stump and the steering wheel feels like (or does) get jerked out of your hands - that is putting tremendous strain on the steering system and can cause it to break.