Good Morning Alan,
We had 2 similar situations as you describe during the past three years.
Same customer ... same tractor.
I was never able to experience the systems when operating the tractor and had to rely 100% on the owners viewpoint.
And do not pretend to know ,for sure,the actual cause of the "sticking, erratic and sometimes binding" symptoms the owner described but I'll be happy to tell you what we did. Things are all OK now with the owner.
It may also help other owners as well.
1. FIRST TIME, we replaced the entire orbital steering control unit... , bleed the system several times to remove all the air pockets.
We were careful to check the new control assy. to insure it was well lubricated INSIDE before installation. We did not want it to DRY at first few seconds of use-- the first time the wheel was turned which could mess up the seals and O-rings .. before the oil was pumped into it.
The original orbital worked just fine at our store, as did the first replacement part..... however ..ater a week... the customer said he could feel an unusual jerky sensation in the steering when mowing with a rotary cutter.
He then report that the only time he had ever felt the symtoms was when he was using that particular implement.
So ... we replaced the orbital again.....
This time, I went to his home and watched him operate the tractor with his rotary cutter... (48" Woods Brand rotary cutter).
He was operating the rotary cutter in 2 positions...
A. .... On uneven or bumpy ground, he would raise the cutter up so that the tail wheel did not roll on the terrain surface.
Therefore the tractor hydraulic system was carrying the payload (cutter) .
It was staving the steering system and with the front of the tractor NOT being as heavy as if the cutter had been rolling instead of being raised.
In this position the tractor was disadvantaged two ways...
Hydraulics were working to raise and carry the full weight of the cutter ... all for many hours and
# 2 .. the front steering and 4wd were disadvantaged because they would light and bouncing a lot due to the counterbalance effect of the raised cutter.
B.
On level ground and driveway right of way cutting...
He would lower the cutter down to so as to allow the tail wheel to just barely skim the surface but, still, not carry any weight. This caused the tail wheel to spin-wiggle-sway-and be in constant motion and quivering all the time. These energies were being transmitted all over the tractor and ... yes all the way to the front end and front tires... Indeed the front tires and axle appeared to have an erratic steering symptom.
This practice/type of operating the rotary cutter had caused severe and premature wear to the bearing and axle of the tail wheels . The extra wear amplified the erratic motions.
The customer was really unaware of the transmissions of these energies throughout his tractor.
Remedy:
1. Never Leave the three point hitch hydraulic control lever in the JAM UP position.
Always push it back towards lower approx. 1/4 inch. This will eliminate the possibility of a mis -adjustment of the lever causing the hydraulic valve/relief valve and pump to work overtime, starve oil from the steering. and overheat relief valves and oils.
2. When using a rotary cutter (or any other similar implements) allow the tail wheel to carry weight.
This will cause it to become a gauging device for cutting height of rear end of cutter ... as well as keep it from doing all the wiggling and gyrating.
3. Use the TOP LINK adjustment on the three point hitch and tail wheel adjustments to level the cutter and to place payload weight on to the tail wheel.
Doing this will also allow the tractor's front end weight and 4wd to assist the steering system and take out the vibrations being transmitted forward by the implement.
These tips caused all the symptoms to disapeared. They have not reoccuured for over a year now.
You should inspect the tractor for any hydraulic lines andtubing that may be bent, crimpled or twisted in such a manner as to restrict oil flow.
None of these issues may solve the symtoms you are experiencing ... but maybe it will help you explore the situation that you have for operating techniques and terrain for help get the FIX.
Good luck,
Steve
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