Traction Steering wheel alignment

[ruffdog]

Don't confuse hydraulic steering to hydraulic assisted mechanical steering. Also, with hydraulic steering, the pump and cylinders could leak allowing the wheel to always turn. I helped a farmer bale hay and I drove a tractor with a leaky steering system. On a side slope, you would have to slowly keep turning the wheel up hill just to go straight.

 

[rScotty]

I worked the Kubota M59 today moving some dirt & snow. What I found was that when the wheels are pointing straight ahead the spinner is always in the 9 o'clock position. It doesn't make any difference where the wheels were pointing when the engine is turned off or what the steering has been doing. Straight ahead always has the knob at the same position. It doesn't drift.

In their workshop manual, Kubota refers to this as "full hydrostatic steering".

For the mechanical guys and gals:
There is no drag link or any mechanical connection leading from the steering box up to the front axle. Instead, there are hydraulic lines leading forward from the steering control box at the bottom of the steering column which go to a single large cylinder mounted parallel to the front axle. Extending from each end of this steering cylinder are left and right hydraulic rams. These rams work through typical ball joints to turn the front wheels. The power steering system has it's own dedicated pump. The cylinder and rams are protected with heavy steel skid plates & bumpers.

With the engine running, the steering is light and positive in spite of wide industrial tires and a full bucket (max bucket load on the M59 is around 4000 lbs). The steering is just one more nice feature of this tractor.

When the engine is not running, the steering is about like an old fashioned non-power steering type. It steers OK and accurately, but requires some effort. In fact, LOTS of of effort if not moving with a load in the bucket.
rScotty

 

[zzvyb6]

If this steering situation really bugs you, mount a rack & pinion steering gear from a small car up front and direct connect the steering column to it. As previously stated, this is not hydraulic assisted steering, but pure hydraulic directed control. In a car or truck, there is a small mechanical connection between the input pinion shaft and the pinion gear. This "T-Bar" [ torsion bar] has a rotary valve on the end of it. In fact, the valve body has mechanical stops on it to prevent relative rotation by more than a few degrees. When the T-bar twists because of steering loads, the valve opens and oil flow is diverted from bypass (open center) mode to the rack assist piston. Same basic principle on heavy cars and trucks which use a recirculating ball type of power gear. You should be able to use the same pump and lines to hook it up. Packaging should not be a problem, just clamp it to the front axle. Tack weld the existing valve in the column or put in a new one. Make sure you get the plumbing right [ right turn torque produces a right tun assist ]. When the steering torque is reduced, the valve closes and you go where you want to head towards. Should not need a new pump unless it is pressure demand. Cars and trucks use approximately constant flow systems and about 100 psi max pressure is available at initial turn in.