3ph lever not returning:
Going by memory as I don't have a WSM at work.
There is a rod that runs from the lever assembly back to the right side of the HST that connects to the upper 3ph arm. The rod has two springs, one on either side of the bracket that attaches to the 3ph arm and there are two lock nuts that can be screwed in/out to adj the spring tension. This spring tension is what "returns" the 3ph lever to neutral. You can access this assembly in the gap between the top of the right rear wheel and the fender.
Your best bet is to shine a light in this area and work the 3ph lever to see how it works. You shoul dbe able to adj accordingly.
Sticking HST treadle peddle.
There are two main causes of this and either can be corrected w/PB Blaster and grease.
1) The pedal has a grease zerk which is visable just above the floor board on it's inboard side. I normally give mine a shot or two every 10 hrs when I'm greaseing the MMM and/or FEL.
2) The linkage from the pedal back to the HST could be dirty/corroded of have debris in the moving surfaces. Give all those working parts a good cleaning w/a garden hose set to it's highest pressure to get all the debis out then give every moving joint a generous soaking w/PB Blaster or similar lubricant/degreaser/ etc.
The pedal will always have some return resistance and will sometimes stick but generally it should return to neutral on it's own. There is also a spring adj for the return for the pedal and it is located on the linkage where it connects to the HST assembly.
re. tractor hydraulics in general:
All hydraulic implement controls on just about all tractors are plumbed in series. Meaning that hydraulic pressure leaves the pump and must pass through all the controls and return to the sump that inturn feeds fluid back to the pump. This is refered to as a closed system and allows the hydraulic fluid to be at it's rated pressure and circulating throughout the system ready to work.
With this setup all the hydraulic controls must be a "power beyond" type control meaning hydro power flows it and out of it when the control is in neutral. This way it feeds the other controls on down the line.
When one works the FEL, it's using the majority of the available hydro power to work the implement which means theres very little to no power available to work any additional down stream implements simultaniously.
So when the 3ph control doesn't return to neutral, it is actually diverting power to the 3ph assembly which causes the squealing your hear. This squealing because the 3ph is usually already all the way up or down and the relief valve is opening. This also causes a very common situation with other implements like the FEL or BH not working because all the hydro power is being inadvertantly used at the 3ph.
Clear as mud?
In larger tractors, they'll actually have 2, 3 or more pumps and separate hydro circuits. One to provide for PS, another for the 3ph and yet another for the FEL & BH. Obviously they won't have the above situation like our single pump BX tractors.
Not to muddy up the above explanation but our BX tractors do have a diverter valve that separates the power steering circuit from the "working" hydro circuits (FEL, MMM, BH etc) which provides the BX's the ability to both steer and work an FEL and/or 3ph simultaniously. But theres a slight tradeoff in performance, the steering will get harder (and sometimes jerky) and the implement will raise/lower slower since both are working and using the same hydro power at the same time. So if you encounter this situation be advised that it is normal.
I HIGHLY recommend getting the owners manual for your model if you don't have one as all these maintenance items are covered in it as well as other important maintenance items.
Well breaks over, time to get back at it.
