Problem with BX1500 3point... Any ideas?

[tomnky]

I have a BX2200 . It developed the problem of not returning to the center that I couldn't adjust out with the linkage.
My problem proved to be a defective Hydraulic control valve , which at that time was $340.00 , but since My tractor had so few hours on it at the time Kubota agreed to pay for the part and I had to pay half the labor which I think amounted to somewhere around $60.00 at the time. If this lever fails to return to center or is not immediately returned manually over a period of time can damage the hydraulic pump.

 

[mtrain]

They are suppose to return to neutral or center position once all the way down or all the way up. It is an adjustment on the right side under the seat . Alot of these tractors are not adjusted properly even when new. I'm always having to point it out to our shop techs before delivery because they overlook it.

 

[Volfandt]

As mtrain posted, the 3ph level is supposed to automatically return to the middle "neutral" position once the 3ph reaches either the full up or down position. There is a feedback linkage rod that connects between the 3ph and the 3ph lever that is adjustable via locknuts.
The locknuts which reside on the rod where it connects to the 3ph either increase or decrease spring pressure between the 3ph and the linkage rod which forces the lever back to the neutral position.
Ideally the lever should "want" to return to the neutral position anytime you release it.
If the lever stays in the lift position after the hitch reaches full up it will load down the hydraulic system to the point of an audible squeal of the pressure relief valve not being able to release the pressure fast enough.

If the lever stays in the full down position it will keep the oil circulating through the down spool port and 3ph piston & cylinder which over time can prematurely wear out their seals, although this would probably take quite a while.

When the valve is returned to the neutral position, the oil flows through the correct ports and also shuts off flow through the piston cylinder. This decreases some wear and tear of constant oil flow through the spool & piston assemblys.

Theoretically, the 3ph should "hold" in the position it reaches when the 3ph lever is returned to neutral. This constitutes a poor mans position control but it's not accurate and may not even hold on machines with either high hrs or the seals have prematurelly worn.

 

[nh DRAGON]

The 2350 I have returns to center as soon as you release the handle. I cant think of why this would not happen on the older tractors, as it would make it difficult to adjust the 1/4" valve to exactly where you need to have it while you are using a rake or box blade?

 

[OlyRick]

Again,
Thank you everyone for your replies.

I got the manual out and read it carefully. According to the manual the 3 point lever should return to the neutral position when the 3 point reaches the bottom or the top of it's travel. All these years it never has. I suspect that the linkage was not adjusted properly. I will try and adjust according to the manual. Hopefully nothing has been damaged by using it this way all these years.

Rick

 

[EE_Bota]

On my BX2200, If I raise up to full up, once the lift is full up, it will return to center. If I tell it to go down, it will go down, and the control lever does not return to center, except after a good long while, so I ignore it.

I suspect BX**00's are all the same as each other, and BX**50's are all the same as each other.

Looking at the schematic of the control valve, and the description of operation in the service manual, internal pressures will work against the spool to cause it to return. In the down position, these pressures will not be nearly as substantial, and hit the side of the spool lands only obliquely, and so the spool will not return to center unless I either hit some bumps in the road, or run as very high throttle.