B7100 Plow blade float

[wisc6000]

A question for the gurus. My kid has a B7100 with the Kubota dozer blade and hydroturn.
The question is that on the lift valve you pull the lever back into the float detent it doesn't float. It provides power down on the blade. Anyone have an idea on the why of this situation.

*I have a B6000 with almost identical valves and it works as it should. Push forward blade up. Pull back blade down. Then pull a bit more it has power down. All the way back into detent it's in float.

 

[TheOldHokie]

A question for the gurus. My kid has a B7100 with the Kubota dozer blade and hydroturn.
The question is that on the lift valve you pull the lever back into the float detent it doesn't float. It provides power down on the blade. Anyone have an idea on the why of this situation.

*I have a B6000 with almost identical valves and it works as it should. Push forward blade up. Pull back blade down. Then pull a bit more it has power down. All the way back into detent it's in float. View attachment 71023

Do you get pressure down when you go into the fourth position e.g
cylinder extends. Or is the cylinder simply locked.

Dan

 

[kubotasam]

A little more info would help. Did the float just stop working? Is the tractor new to your son? Is it possible that someone installed a valve without the float option?

 

[wisc6000]

It's new to my kid.
It's been about 7-8 months since I ran it. Of course as snow is coming he suddenly remembered that I told him to look into it back then.... I better clarify as to the validity of what I remember. I'll get back to this thread once I am positive about the functionality.

Thanks in advance.

 

[wisc6000]

While waiting for the kid, here's an alternator and snow blower attachment I fabricobbled on it in a short time frame. Including the 2:1 small block chevy chain in oil bath reduction. That little denso alternator cranks out some serious power. And that blower does a great job. *Other than not being able to float on the ground.

Oyeah, the previous owner said it would overheat in hot weather for some reason.

 

[wisc6000]

Just a couple more.

 

[kubotasam]

Nice Work!!!!!

 

[RCW]

Fabricobbled…. I like that!

I resemble that remark.

I’ve called it redneck engineering….might have to change my terminology.

 

[Pau7220]

Way nice work!!

Oyeah, the previous owner said it would overheat in hot weather for some reason.

And he was serious when he said that I'm sure. I just hope overheat didn't mean running it for hours with the temp gauge needle buried.
Good luck!

 

[wisc6000]

The kid says he'll do a function report on the hydraulics today and get back to me.
Yeah, nice radiator huh.. 40 years of crap buildup.
No temp or oil pressure gauges on these things so I trust the cloud of steam was the last owners clue it was getting hot.

Pro tip for owners of these 40 year old machines:
They cheaped out when designing the small tractors and don't have a water pump and rely on the thermosiphon principle. For 35 years I wrestled with overheating on my B6000 and I cured it with a simple mod. I drilled a hole in the radiator cap guts so it won't build pressure. It still seals to the top lip. Then installed an expansion tank. It runs 180-195 even in the hottest weather now.

 

[wisc6000]

Plow lift and drop are operated by the left lever and hydroturn by the right. Left lever seems to have no lock float as it's pull/push for flow only.
On my 6000 the right lever does the lift and left the turn.

I wonder if the hoses have been reversed since new on this one. Give a look at the pics and point me in a direction to solve this no float scenario.

Loose wires are for future additions of lighting etc.

 

[TheOldHokie]

Plow lift and drop are operated by the left lever and hydroturn by the right. Left lever seems to have no lock float as it's pull/push for flow only.
On my 6000 the right lever does the lift and left the turn.

I wonder if the hoses have been reversed since new on this one. Give a look at the pics and point me in a direction to solve this no float scenario.

Loose wires are for future additions of lighting etc.

The spool with the longer end cap is the one with a fourth position. That usually indicates float either with with or without detent. The fourth position is engaged when the spool is moved fully ioutward. What direction the lever moves to shift the spool inward depends on the lever/spool linkage. Looking at the pictures that would appear to be lever pushed forward which I would think means blade down. All the way forward is blade float.

Dan

 

[wisc6000]

Aha! It appears I'm underthinking it. Seems we just have to swap the hoses at the valve for the lift cylinder for it to float as it now lifts when pushed forward to the latch position. The latch works with the engine off/no pressure but not when running. A simple tightening of that detent should do it.

Perhaps next week we will do the changeover from the dozer blade to the snowblower. Then we'll see how it chooches. I'll post the findings.

Thanks in advance.

 

[wisc6000]

Still no action on the changeover.

 

[wisc6000]

Still no action and I trust he'll wait until the snow is a foot deep.
In the meantime Merry Christmas to all.

 

[wisc6000]

Seems he's using the plow blade for the couple little 1-2 inch snows we have had. Not my problem!

 

[wisc6000]

After about 5 inches of snow he got to it today.

Pushing the valve forward to the detent lock position does not provide float as we thought it should. It provides powered flow to the cylinder. Up or down depending which hose is on which port. Presently it powers down. Pulling the valve to the other spring loaded end provides opposite flow (up) to the lift cylinder as expected.

Does anyone know who made these valves? Back then Kubota had these attachments and valves made by an American supplier. If I found the valve maker I would likely have better luck at getting data, new guts etc. or even replacing the valves. I imagine there is a standard size description or category I could look into.

thanks.

 

[TheOldHokie]

After about 5 inches of snow he got to it today.

Pushing the valve forward to the detent lock position does not provide float as we thought it should. It provides powered flow to the cylinder. Up or down depending which hose is on which port. Presently it powers down. Pulling the valve to the other spring loaded end provides opposite flow (up) to the lift cylinder as expected.

Does anyone know who made these valves? Back then Kubota had these attachments and valves made by an American supplier. If I found the valve maker I would likely have better luck at getting data, new guts etc. or even replacing the valves. I imagine there is a standard size description or category I could look into.

thanks.

That is really odd because the spool appears to have 4 positions.

You don't need to know much about the old valve to replace it:

• Approximately 10 GPM, open center with power beyond and two spools
• Spool 1 - tandem center, 4 way, 4 position, spring center, and float detent in fourth position
• Spool 2 - tandem center, 4 way, 3 position, spring center

With a two lever control run you about $150. With joystick control add another $50.

Dan

 

[wisc6000]

Thanks Dan. I imagine we'll just take it apart and visually see what it's doing. Or run some air through it to see what the flow is doing. Yes it makes no sense other than this 40 odd year old dealer installed plow kit and valves perhaps were installed wrong when new. Maybe there's a plug or some device in the float position that was supposed to be removed when new.

Now that I have your terminology I'll sniff around the web for answers.

 

[TheOldHokie]

Thanks Dan. I imagine we'll just take it apart and visually see what it's doing. Or run some air through it to see what the flow is doing. Yes it makes no sense other than this 40 odd year old dealer installed plow kit and valves perhaps were installed wrong when new. Maybe there's a plug or some device in the float position that was supposed to be removed when new.

Now that I have your terminology I'll sniff around the web for answers.

Here is one of many.

Monoblock Hydraulic Directional Control Valve, 2 Spool w/ Single Float Detent, 11 GPM

This Monoblock Hydraulic Directional Control Valve uses 1 Float & 1 "A" Spool. It has a capacity of 11 GPM. Free Shipping

summit-hydraulics.com

Dan