Steering logic.

[J_J]

Just curious if every ones PT works like mine. My steering seems to have priority over the lift and tilt circuits. This has got me in trouble a couple of times. Turning while trying to miss an object in the way .

 

[Gravy]

Yep. Mine does it, too. As far as I can tell, there's a priority valve that favors steering. If the steering wheel is at or near full lock, the lift/tilt doesn't work, even at a stop. I have to remember to turn the wheel back just a bit.

Dave

 

[BobRip]

Yep, that the way it is supposed to work, steering is the priority for that particular pump. I guess this is considered safer, but as you found out it's not always so. Steering does seem pretty important though.

Bob Rip

 

[cqaigy]

Me too. And at full turn had the lift stop and have plowed into a few things while trying to lift to clear it. /forums/images/graemlins/tongue.gif
But if you back off of the turn just a bit then the lift works.

 

[Spiffy]

I think we're talking about the same thing here, but if not maybe the 2445 is slightly different. I get full articulation, without any pressure issues. However, the steering wheel goes just a bit further each way, at these points I don't have pressure.

 

[MossRoad]

Yep. Mine, too. /forums/images/graemlins/wink.gif

If it's any consolation, my IH does the same thing. At least it did before the steering broke. Now I can only go forward and backward, so I don't run into any lock problems. /forums/images/graemlins/tongue.gif

 

[J_J]

I think that if I had a hydraulic circuit layout, I just might think about replumbing the system to the way I want. Does anyone know a specific reason for the steering to take priority?

 

[Spiffy]

I'm just taking a wild guess here, but I don't think it's a matter of priority. I'm guessing they're plumbed in parallel, but when the steering wheel is fully to one side or the other the steering valve leaves an "open path" for the fluid (perhaps an oversight or an imbedded safety on the steering valve). Of course, then [as fluids take the path of least resistance] it will go through the steering valve instead of excerting any for force to other controls.

Again, just a wild guess. /forums/images/graemlins/crazy.gif

At the risk of highjcaking the thread: Does anyone [yeah I know, us 24XX guys are oddballs] have a good scheme to mechanically route a secondary steering aparatus to the back? Better yet: a lever? /forums/images/graemlins/smile.gif I suppose to do it proper, one should order another steering valve, and a triple two-way solenoid, but $$$! /forums/images/graemlins/frown.gif

 

[Spiffy]

I should note: I can feel the wheel location before those limits, so it doesn't bother me...."not bothering me" also may be that I've only put 3 hours on it! /forums/images/graemlins/grin.gif

 

[MossRoad]

I''ve often thought of putting in a joystick for steering. It would be handy for a couple of reasons. I could see how it would be handy back at the backhoe's operation station. Maybe a valve in parallel with the main steering valve? Either one would do the trick, although I see lots of hoses in your future! /forums/images/graemlins/tongue.gif

 

[J_J]

Next time you are on the machine, do this test. While turning, pull back on the lift handle. Turn the wheel back and forth and see if the lift stops until you have stopped turning.. Mine does.

 

[Gravy]

I assume that it's intentionally prioritized that way. From a safety/liability standpoint, I'd think steering would have to take precedence over attachment lift/tilt. I can see more likelihood of a lawsuit over a steering failure than a lift/tilt failure. Personally, I'd prefer independent circuits for each, but that would likely add complexity and cost.

Dave

 

[BobRip]

When I took the class at Tazewell in 2000, I was told that the steering intentionally had priority. At least that's what my memory says.
I am attaching a picture of a drawing of the steering hydraulics from the manual. I hope this helps. It looks to me that when you steer to the stop the flow is stopped to the lift/ tilt valve bank and the releif valves opens for this pump. This is my assumption.

Bob Rip

 

[BobRip]

Did anyone else take the class on the PT in Tazewell? I learned a lot, and yet I don't think anyone else has referred to it. Do they still teach it?

Bob Rip

 

[Spiffy]

I'm not quite sure how the class was done when you had it, but was pretty impressed this summer.

The mechanic that gave us the demo just went through all the critical points and Q&A after I got through demo-ing.

My books don't have that schematic, but I'm guessing they're pretty similar.

 

[Spiffy]

J_J

Maybe I'm not conducting the test right or maybe there's something plumbed "wrong" in my machine, but except for the very ends of steering wheel travel (which is beyond full articulation), it doesn't seem to matter whether I start steering while lifting or start lifting while steering, it lifts a slight bit slower, but keeps lifting.

 

[cqaigy]

<font color="red">steer to the stop the flow is stopped to the lift/ tilt valve bank and the releif valves opens for this pump. This is my assumption.
</font>

Ditto. I assumed that this is what was happening. i.e. relief valve opening taking pressure from the lift circuit.

 

[cqaigy]

Spiffy,

My machine acts the same way. Stop lift at full turn, slower lift when turning but not at full articulation and full speed turn when sitting still.

 

[J_J]

From looking at the hydraulic circuit, I don't see why one could not tee off the output of the pump through a relief valve, and one hose to go directly to the lift and tilt valve, and the other hose back to tank Then, just put plugs in the steering valve where the lift and tilt circuit was. They would then be equal.

Parts 1 relief valve.
1 tee.
2 short hoses and fittings.
2 plugs

 

[Spiffy]

Looks like a good plan to me J_J. I'd have to look at the schematic again, but since you're going in parallel, the additional relief may not be required. Let us know how it works out! /forums/images/graemlins/smile.gif Mostly just curious, since mine doesn't bother me, that's a mod I can proably skip.

MR: You guessed it; I'm contemplating a rear joystick to make BH life easier. Also would be great if I ever mount a 3pt blower; I think it'd be a snow moving machine with a blower on one end and snow bucket on the other. /forums/images/graemlins/grin.gif