Loader "dead" spot

[k0ua]

Reply back and tell us that you do understand there are 2 dump positions, dump under pressure and the regenerative position. When using the regen position, and you have a good load in the bucket, and it dumps by itself it takes a second for the oil to fill the cylinder to start it to move back up, this is normal. On the Kubota, and I assume yours also, the dump under pressure position is to the right, and the regen position is further to the right, as in all the way you can move the lever. If this is the "problem" then there is no problem, this is normal operation. If this is not it, then I don't know, but there are guys on here who do.

James K0UA

 

[Rhon]

I understand the two dump thing now and you're correct. There are two positions to the right. I went back and re-read the manual on this. Hard right is fast dump and the regenerate cycle. I pretty much think "operator error" has been a big factor with this now. If I slow down and not use the fast dump it seems to work better. It's a forest for the trees type thing. Until someone else points it out, you don't really see it...

 

[k0ua]

I understand the two dump thing now and you're correct. There are two positions to the right. I went back and re-read the manual on this. Hard right is fast dump and the regenerate cycle. I pretty much think "operator error" has been a big factor with this now. If I slow down and not use the fast dump it seems to work better. It's a forest for the trees type thing. Until someone else points it out, you don't really see it...

cool, good luck

James K0UA

 

[MD09]

I was told to lift the boom up and that would purge the air from the system. And it is loose where it pins together but not enough to cause the hesitation. I'll go back to the book and check it out. It's more a aggravation than anything else but I thought I'd check. Thanks for the help

Remeber Air will travels UP. If you have air in the bucket cylinder lower the boom and let the air work it way up to the valve. Put soem pressure on teh side you are concerned with and this will help bleed the system without loosening connections.

 

[Rhon]

Will do , thanks

 

[jinman]

Just to add one point. . . The engine rpm should be 2000 or higher to provide full flow to the bucket. I doubt seriously that you have air in the system, but sometimes with fast/regen dump you actually get cavitation in the cylinder and a small air pocket forms under vacuum. Full hydraulic flow will make the delay between vacuum and pressure much shorter and reduce the noticable lag.

 

[Rhon]

Great point. I can't say for sure if I run them that high or not. As soon the mud 'firms up' a bit, I'll give it a try and see if that could be my issue. It's been raining here pretty much since I don't know...last october. I'm sure it mostly operator error cause this little tractor is really great.

I appreciate all the suggestions. Glad I found this site.

 

[MD09]

Just to add one point. . . The engine rpm should be 2000 or higher to provide full flow to the bucket. I doubt seriously that you have air in the system, but sometimes with fast/regen dump you actually get cavitation in the cylinder and a small air pocket forms under vacuum. Full hydraulic flow will make the delay between vacuum and pressure much shorter and reduce the noticable lag.

Cavitation in the cylinder???? from a slow motion? Please explain.
Rob

 

[jinman]

Cavitation in the cylinder???? from a slow motion? Please explain.
Rob

Rob, the cavitation occurs when the bucket is full and you move the lever to regenerative dump. Instead of the fluid driving the cylinders, the weight of the load pulls the bucket downward, creating a vacuum on the back side of the hyd. ram. That vacuum can actually instantaneously cause the fluid to outgas tiny gas bubbles (cavitation). We aren't talking much here, but since the pressure from the hydraulic system isn't driving the ram, there's a lag until it catches up with the bucket and builds pressure where there was just a vacuum. If the engine is at low rpm, it takes a much longer time to develop that pressure. You can reduce this effect by putting an orifice inline with each cylinder (right on the cylinder), but this also will slow down your regenerative dumping speed. It's a tradeoff.

Yep! I know when you think of cavitation, it is normally high speed pump impellers or boat/ship propellers, but it happens in slow speed high vacuum situations too. We just normally call it outgassing instead of cavitation. It's what happens when you pop the top on a soda bottle.

 

[yoder]

Would the float postion have anything to do with his issue?