kubota M105s scv's dont work in one direction at 2000+ rpm

[mrtiggy]

So my 2006 M105 with 420 (I think this is accurate, bought it with 370hrs) hours on it seems to have an issue with the scv's. Both valves will not work very well if at all when the rpm's are around 2000 rpm. They seem to work well up until this rpm. I only use the tractor for snow blowing and only have the one attachment to test on. I was just running the tractor the other day, going over it for this winter, and I found that if i just pushed the levers forward the tiniest amount the blower shoot would rotate but any further with the lever it just locks up. Pulling the level backwards works fine at any rpm. This doesn't sound like a problem that would be solved by changing the hydraulic filters??? Is there any kind of adjustments that might need to be done? I would like these to work 100% as it is very frustrating to try and snowblow only to have no real control over your shoot. I do residential driveways with this and I am always maneuvering the shoot, or at least trying to.
Thanks

 

[kennyd]

This sounds normal, it's the regen or regenerative function of the valve that's causing that. The quick answer is to push the lever further right to get through that funtion.

Here is a good read: http://www.tractorbynet.com/forums/kubota-buying-pricing/9403-3-position-valve-vs-4-a.html

There are many more if you search the term "regen" especially in the Kubota forum.

 

[Tx Jim]

My Kubota M7040 doesn't have any regenerative function on the rear remotes(scv's). I'd be checking the male & female couplers to be sure they are engaging properly to allow good oil flow. Does snow blower have correct male hyd tips for your tractor?

 

[Winmac]

I Can't speak specifically for you tractor but remote valves are often configurable dependent on use. If it's single acting vs double acting there may be a knob to rotate etc. Also some have a kick out feature where you push the lever down it locks and once the ram strokes out it kicks into neutral, best advise I can give would be to find the operators manual for the tractor.

 

[mrtiggy]

kennyd - I do not have the option of moving either of my two levers for the rear scv's to the right, just back and forth.
Tx - Thank for the suggestion I will take a look, I may try to get a picture of the ends to post.
Winmac - This makes sense to me, I am currently trying to find an owners manual on line. I have bought a workshop manual but do not see any reference to valve operation.

 

[kennyd]

Sorry, I mistaking assumed this was a front blower operated from joystick control.

 

[Winmac]

I was doing some googling about this and I did learn that if the 105s tractor has more than one remote valve one will have a float detent. Which fits your description of operation( valve locking in), I also read that a flow control valve is included in the valve stack. With multiple valves. Perhaps lowering the flow would make for stable operation in high rpm

 

[mrtiggy]

thanks for the extra leg work. I actually had found something earlier today that mention I could possibly have a flow control valve, be damned if I can find it again. So i will be looking for that next time with the tractor.

 

[MHarryE]

Are you sure yours doesn't have float? It sounds just like mine - if I push the lever all the way forward I go into float mode move it a little way and I have hydraulic power. I have flow control on all 4 remotes, a small knob by each valve but turning them effects flow in both directions. The tractor to which I am referring is 7 years newer than yours so they probably aren't exactly the same.

 

[mrtiggy]

yes i believe i do have a float valve, but the problem is not when I push it all the way it is just off the neutral position...when pushed towards the front of the tractor. I will be checking for any type of flow control, it sure seems like this would solve the issue.