Laser grading hydraulic valve issue.

[Complete Turf Care]

Voltage or hyd pressure.

There should be o-rings around the solenoid shaft going into the valve. They should be sufficient if there is no hyd spike.

The proportional valve works in relation to the signal it receives, could be large or small increments.

Is there a sensitivity adjustment on the valve or in the laser system.

There are adjustments on the laser system. One is for reaction time. I can increase or decrease the amount of time it will take to allow the system to change the blade height.

The other adjustment is to increase or decrease the 'dead zone' on the receiver. This will cause the blade to change height when it is more than the 'dead zone' off grade. I can set this to adjust the blade height at as little as 1/8" or as much as 2".

These adjustments are to avoid excessive movement of the blade (causing excessive heat). I will decrease the 'dead zone', and reduce the reaction time, as I get closer to finished grade.

However, I don't think either of these adjustments have anything to do with my 'coil' failure.

 

[J_J]

Did you say whether the failure was fluid pressure pushing past the o-rings or a cracked coil.

Are you using factory o-rings or just any o-ring.

If you remove the coil, can you manual push the center rod to push the spool rod in or out.

Can you see fluid leaking past the o-rings as you apply/cause pressure .

If the hyd pressure is exceeding the solenoid valve ratings, you might consider reducing the relief setting on the laser grader valve. If the grader does not have a relief valve, the remote valve should have one.

If you are getting large hyd spikes from the grader hyd system, a hyd gage might help you monitor and troubleshoot the hyd system.

 

[Complete Turf Care]

Did you say whether the failure was fluid pressure pushing past the o-rings or a cracked coil.
The failure doesn't seem to be o-rings, but something in the coil.
Are you using factory o-rings or just any o-ring.

If you remove the coil, can you manual push the center rod to push the spool rod in or out. I haven't tried this

Can you see fluid leaking past the o-rings as you apply/cause pressure .

If the hyd pressure is exceeding the solenoid valve ratings, you might consider reducing the relief setting on the laser grader valve. If the grader does not have a relief valve, the remote valve should have one.

If you are getting large hyd spikes from the grader hyd system, a hyd gage might help you monitor and troubleshoot the hyd system.

I called the guy who sold me the system today. He said it has to be some kind of back pressure that is causing the 'coil' to fail. He suggested I check with my Kubota dealer to see if there is another way to dump the return oil back into the tractor tank, besides the remote valve.

I was near a Kubota dealer, and stopped in to ask. A mechanic said that the only way he could think of to dump the oil back into the tank, would be to add a 'T' into the FEL return line.

The mechanic also suggested that I check the male quick connectors to see if they match my tractor's remote valve's female connectors. I discovered that the male connectors on the laser blade have a 'ball' type and the female part on the tractor is the 'flat tip' type. (Not sure if that's the correct term, but they are different)

Do you think the different types in the quick connections could cause a restriction? If that would be the problem, it would surely be an easy fix.

And, thanks again J_J for helping me with this issue.

 

[aczlan]

I called the guy who sold me the system today. He said it has to be some kind of back pressure that is causing the 'coil' to fail. He suggested I check with my Kubota dealer to see if there is another way to dump the return oil back into the tractor tank, besides the remote valve.
I was near a Kubota dealer, and stopped in to ask. A mechanic said that the only way he could think of to dump the oil back into the tank, would be to add a 'T' into the FEL return line.

The backpressure is probably caused by using the 3 point while the lever for the remote was engaged. Look at the back of your tractor, there is a fill port back there that you can put an adapter (such as seen at: http://www.tractorbynet.com/forums/attachments/115722-post-driver-hydraulic-hook-up.html#post1334294 ) onto and have a zero pressure return.

Aaron Z

 

[J_J]

On the ball an poppet type QD's, they should match.

I have never seen a flat face QD used with a b all or poppet type QD.

Again, match up the QD's as to manufacturer.

The fill cap is another to return the fluid directly from the laser grader.

A hyd gage would be helpful in sensing any hyd pressure.

Just add a tee in the pump hyd line and put it where you can see it.

 

[oldnslo]

The mechanic also suggested that I check the male quick connectors to see if they match my tractor's remote valve's female connectors. I discovered that the male connectors on the laser blade have a 'ball' type and the female part on the tractor is the 'flat tip' type. (Not sure if that's the correct term, but they are different)

Do you think the different types in the quick connections could cause a restriction? If that would be the problem, it would surely be an easy fix.

And, thanks again J_J for helping me with this issue.

Yes the different style QD's could cause excessive back pressure along with the increased flow potential from the Kubota. It looked like there may be a tank line gauge port on the valve body. If there is can you install a gauge in that port and see what the pressure does while the system is in operation.

 

[Complete Turf Care]

Here are pics of my male QD on the blade, and the female on the tractor. I'm going look at the valve to see if there is a place I could put a gauge.

 

[oldnslo]

On the picture in post #7 there appears to be plugs labeled TG & GP. Not sure if that is for tank gauge & gauge pressure or some other function.

Is the QD on tractor a flat face or poppet style? Almost looks like poppet style where there would be a cone shaped pice in the middle of the QD. Occasionally these will interchange with ball style but I have had them fail and block the flow which would then create back pressure on the tank line.

 

[Complete Turf Care]

On the picture in post #7 there appears to be plugs labeled TG & GP. Not sure if that is for tank gauge & gauge pressure or some other function.

Is the QD on tractor a flat face or poppet style? Almost looks like poppet style where there would be a cone shaped pice in the middle of the QD. Occasionally these will interchange with ball style but I have had them fail and block the flow which would then create back pressure on the tank line.

On the tractor, the QD is a poppet style, and on the blade, they are ball style. I'm gonna change those before I use it again.

Here are some more pics of the valve. I don't know if any of these ports would be for a gauge. And at the tip of my ink pen is where the oil comes out when the 'coil' fails.

 

[aczlan]

Look where the red box is in this picture. You will find an orangeish/yellowish cap that can be used as a pressure free tank return if you drill it out and tap it.


Aaron Z

 

[Complete Turf Care]

Look where the red box is in this picture. You will find an orangeish/yellowish cap that can be used as a pressure free tank return if you drill it out and tap it
Aaron Z

Yes, here is a pic of the filler cap. And, I know for sure that I did operate the 3pt hitch when the first coil failed. The only way I could get my tiller and my blade to fit on my trailer was to hook the tiller on the tractor, raise it all the way, then hook the blade on the drawbar, and transport it on the trailer like that.

If I want to dump the oil into the filler cap, would I just plug one hose into the remote valve, and the other would go to the filler cap?

 

[aczlan]

Yes, here is a pic of the filler cap. And, I know for sure that I did operate the 3pt hitch when the first coil failed. The only way I could get my tiller and my blade to fit on my trailer was to hook the tiller on the tractor, raise it all the way, then hook the blade on the drawbar, and transport it on the trailer like that.
If I want to dump the oil into the filler cap, would I just plug one hose into the remote valve, and the other would go to the filler cap?
View attachment 349918View attachment 349919

Yes. The only caveat being that when the lever (on the tractor) is pushed/pulled to turn on the remote, your 3 point hitch will not raise.

Aaron Z

 

[Complete Turf Care]

You might consider a 3000 psi hyd gage in the system to monitor and trouble shoot the hyd system. Cost about $30

Sample test set.

I think this is my next step in this process. How would you suggest I put a gauge in my system?

 

[aczlan]

I think this is my next step in this process. How would you suggest I put a gauge in my system?

I would use the following:
1x 1/2" Quick coupler set: 1/2" NPT QUICK COUPLER F/F S20-4
1x 1/2" Tee: 1/2 X 1/2 X 1/2 NPTF TEE
2x 1/2" nipples: 1/2 NPT HEX NIPPLE
1x 1/2" to 1/4" bushing: 1/2 NPT TO 1/4 NPT BUSHING
Gauge: 5000 PSI 2.5" LF LM GAUGE CF1P-350-A

That would give you: male quick connect > 1/2" close nipple > Tee > 1/2" close nipple > female quick connect
Then off the other side of the tee you would put the bushing and the gauge.

Depending on where your tractor remotes are located, it might be hard to read the gauge like that and the length might be unwieldy (depending on how your hoses run). If that's the case some options are:
Add a hose to the gauge so that you can have it in a more convenient location:
Hose: Surplus Center (pick a length)
Coupler: 1/4 X 1/4 NPTF COUPLER
The hose goes into the bushing on the tee and the coupler is to connect the gauge to the hose.

Add a hose between the male quick disconnect and the tee so that you have some flex:
Hose: 1/2" X 12" 1/2 NPTM X 1/2 NPTM 3500 PSI HYD HOSE
The hose replaces the nipple between the male quick disconnect and the tee.

Total would be $40-$56 depending on what you got and shipping would be another $12ish.

I would use a liquid pipe joint sealer on the threads such as: Oatey Great White 1 oz. Pipe-Joint Compound-312291 at The Home Depot

With the above setup, you could put the gauge on either line and watch the pressure while working to see what it gets to.

Aaron Z

 

[Complete Turf Care]

I picked up the fittings to put in a valve. I'll plug one end into the tractor, and plug the hose from the blade into the other end. I got most of the fittings from my local Tractor Supply, and the valve at a local machine shop.

I'll put it all together tomorrow and try it out to see if I have any back pressure.

 

[aczlan]

Looks great. One note, if those are black iron and galvanized reducers, I might replace them with Steel Hydraulic Adapter, 3/8 in. M x 1/4 in. F - Tractor Supply Co. and Steel Hydraulic Adapter, 1/2 in. M x 3/8 in. F - Tractor Supply Co.
IIRC Black Iron and Galvanized fittings are only rated for ~600PSI

Aaron Z

 

[Complete Turf Care]

Looks great. One note, if those are black iron and galvanized reducers, I might replace them with Steel Hydraulic Adapter, 3/8 in. M x 1/4 in. F - Tractor Supply Co. and Steel Hydraulic Adapter, 1/2 in. M x 3/8 in. F - Tractor Supply Co.
IIRC Black Iron and Galvanized fittings are only rated for ~600PSI

Aaron Z

Thanks Aaron. I had picked up this at Tractor Supply, but when I got to the machine shop, he said that it wouldn't work. So he gave me the galvanized reducers.


I went back out and put it all together and plugged it into the tractor. It's getting late now, so I'll hook up the blade tomorrow and try it out.

 

[Complete Turf Care]

I got everything hooked up and took it for a test drive. You can see in this first video that the pressure on the 'return' side stayed under about 200 psi, but when I uploaded the video, I noticed that it spiked up to about 800 psi for about 2 seconds at 48 seconds into the video. I'm not sure what caused the spike, because I didn't see it until I watched the video again on my computer. Could this be enough of a spike to cause my back pressure problem and make my coil fail?

I'll post another video with the gauge on the 'pressure' side hose later.

 

[Complete Turf Care]

Here is another video with the gauge on the 'pressure' hose. You can see that it fluctuated between about 500 and 1000 psi when the blade was within it's working range. But, when the blade couldn't go any higher, the pressure would peak at about 2400 psi and stay there until I drove to an area where the blade would get back into it's working range. Really not much to see in this video.

And, yes, there is a lot of oil leaking from my gauge setup. I used some kind of pipe dope from Tractor Supply. I'll probably take it apart and use some teflon tape before I use it again.

 

[J_J]

Where is the return/OUT hose dumping the laser valve expended fluid?

You should not have much back pressure with the OUT hose going directly to tank.