Youli MB3 valve question.

[K5lwq]

Merry Christmas!

I installed a Youli MB3 valve with third spool on my loader in anticipation of a new grapple from EA. I posted a picture and thats when I noticed it was missing a screw on the joystick. I am not sure when or where it came up missing but I don't see it in the box or around where I installed the valve.

When I tested the valve, I noticed that when you are lifting the boom and dumping the bucket at the same time the boom starts to fall. It will raise and curl up at the same time no issue. It will perform all other functions independently perfectly. So, my question is could this screw be the issue or is that just the design of this valve? If it is the design, I have never seen that before and think that is something I will not like about this valve. Any help would be greatly appreciated.

 

[K5lwq]

Update.

I tried to put one of the other screws in this hole and it just slides in and out. No threads. I am guessing I did not loose anything but it is designed to use only three screws on the joystick. I am still curious as to why the boom falls while raising and curling down at the same time. Maybe a faulty check valve?

 

[oldnslo]

Possibly the load check valve on the raise lower is not sealing properly. Under certain load and spool positions this could allow the loader to drop even while trying to raise.

Using only the raise function While try to raise the loader very slowly does the loader want to drop or will it stay up?

 

[K5lwq]

It seams to be holding fine if I only raise. I haven't picked anything up with yet so all test was just the weight of the bucket. I did test slow as well as normal speed. Thanks.

 

[Xfaxman]

Does the joystick have float?

 

[rScotty]

Update.

I tried to put one of the other screws in this hole and it just slides in and out. No threads. I am guessing I did not loose anything but it is designed to use only three screws on the joystick. I am still curious as to why the boom falls while raising and curling down at the same time. Maybe a faulty check valve?

What's needed here is some more information. BTW, that's a nice looking installation you did.
Since both the bucket curl and boom raising functions draw from the same supply source - in this case the pump output - seeing the boom falling slightly when the bucket curls may be unavoidable at low flow.
My guess at this point is that it may be due to the internal geometry of the loader valve or it could depend on the way that the hydraulic cylinders are configured end-for-end. Try running the same test with the fluid warmed up at medium RPM and see if the same thing happens then.
rScotty

 

[K5lwq]

Does the joystick have float?

It does have float on first spool.

 

[K5lwq]

What's needed here is some more information. BTW, that's a nice looking installation you did.
Since both the bucket curl and boom raising functions draw from the same supply source - in this case the pump output - seeing the boom falling slightly when the bucket curls may be unavoidable at low flow.
My guess at this point is that it may be due to the internal geometry of the loader valve or it could depend on the way that the hydraulic cylinders are configured end-for-end. Try running the same test with the fluid warmed up at medium RPM and see if the same thing happens then.
rScotty

Thanks Scotty! I will try that test and report back. I can learn to live with it as I only see the issue raising and dumping at same time. The old valve would only do one function at a time anyway. I just find it strange that it will raise and curl back with no issue.

 

[K5lwq]

Bad news job is interfering with tractoring. Good news new Grapple will be here Tuesday!! I will be able to run the test on Saturday and report back. Then I will run the new stainless lines to power the grapple and will post pictures of the complete set up. Thanks for everyone's help!

 

[K5lwq]

What's needed here is some more information. BTW, that's a nice looking installation you did.
Since both the bucket curl and boom raising functions draw from the same supply source - in this case the pump output - seeing the boom falling slightly when the bucket curls may be unavoidable at low flow.
My guess at this point is that it may be due to the internal geometry of the loader valve or it could depend on the way that the hydraulic cylinders are configured end-for-end. Try running the same test with the fluid warmed up at medium RPM and see if the same thing happens then.
rScotty

I was able to run some more test. Warmed up tractor and fluid for each test.

Operated at several different RPM settings and found if I curl down while raising boom the boom still falls. If I feather very carefully I can get it to raise or hold while using both functions.

If I curl up and raise at same time everything seems normal. If RPM is to low, it will stop raising the boom and curl up then resume raising the boom.

If I raise boom up then try to feather it back down the system loads as if trying to lift tractor or lifting a heavy load. If I idle down then lower by pushing fully on joystick, it does not strain at all. Not sure why it labors if I just barley push on the joystick to lower boom.?

I am starting to think the new valve has regen and that is why it is performing this way. I will have to get with the folks I got the valve from to find out. They do not open again till next week.

If anyone has any idea of what is happening I would appreciate the info.